Prime and boost vaccination against HER2/neu in breast cancer

Breast cancer is the most common cancer among women with approximately 180,000 new cases being diagnosed yearly in the United States (1). HER2/neu gene amplification and subsequent protein overexpression is found in 20–30% of breast cancer patients and can lead to the promotion of various metastasis-related properties (2–4) and/or resistance to cancer therapies such as chemotherapy and radiation (5). ^ The protein product of the HER2/neu gene, p185, is a proven target for immunological therapy. Recently, passive immunotherapy with the monoclonal antibody Trastuzumab® has validated an immunological approach to HER2/neu+ breast cancer. Immunity to HER2/ neu, when found in breast cancer patients, is of low magnitude. Vaccination-induced HER2/neu-specific antibodies and HER2/neu-specific cytotoxic T cells could result in long-lived immunity with therapeutic benefit. Many features of DNA vaccines and attenuated viral vectors may contribute to the efficacy of prime-boost vaccination. In particular, vaccines capable of eliciting strong cell-mediated immunity are thought to hold the greatest promise for control of cancer (6–9). ^ To optimize cellular immunization to HER2/neu in my study, the HER2/neu gene was presented to the immune system using a priming vector followed by a second vector used as the boost. In both animals and humans, priming with DNA and boosting with a poxviruses, vaccinia or canarypox appears to be particularly promising for induction of a broad immune responses (10). ^ I tested three gene vaccines encoding the HER2/neu gene: (1) a plasmid, SINCP, that contains part of the genome of Sindbis virus; (2) Viral Replicon Particles (VRP) of Venezuela Equine Encephalitis virus (VEE) and (3) E1/E2a-deleted human Type 5 Adenovirus. In SINCP and the VRP, the caspid and envelope genes of the virus were deleted and replaced with the gene for HER2/neu. SINCP-neu, VRP- neu and Adeno-neu when used alone were effective vaccines protecting healthy mice from challenge with a breast cancer cell line injected in the mammary fat pad or injected i.v. to induce experimental lung metastasis. However, SINCP-neu, VRP-neu or Adeno-neu when used alone were not able to prolong survival of mice in therapeutic models in which vaccination occurred after injection of a breast cancer cell line. ^ When the vaccines were combined in a mixed regimen of a SINCP- neu prime VRP-neu or Adeno-neu boost, there was a significant difference in tumor growth and survival in the therapeutic vaccine models. In vitro assays demonstrated that vaccination with each of the three vaccines induced IgG specific for p185, the gene product of HER2/neu, induced p185-specific T lymphocytes, as measured by tetramer analysis. Vaccination also induced intracellular INF-γ and a positive ELISPOT assay. These findings indicate that SINCP-neu, VRP-neu and Adeno-neu, used alone or in combination, may have clinical potential as adjuvant immunotherapy for the treatment of HER2/neu-expressing tumors. ^

The design and evaluation of a 2D dose verification system for intensity modulated radiotherapy

The usage of intensity modulated radiotherapy (IMRT) treatments necessitates a significant amount of patient-specific quality assurance (QA). This research has investigated the precision and accuracy of Kodak EDR2 film measurements for IMRT verifications, the use of comparisons between 2D dose calculations and measurements to improve treatment plan beam models, and the dosimetric impact of delivery errors. New measurement techniques and software were developed and used clinically at M. D. Anderson Cancer Center. The software implemented two new dose comparison parameters, the 2D normalized agreement test (NAT) and the scalar NAT index. A single-film calibration technique using multileaf collimator (MLC) delivery was developed. EDR2 film's optical density response was found to be sensitive to several factors: radiation time, length of time between exposure and processing, and phantom material. Precision of EDR2 film measurements was found to be better than 1%. For IMRT verification, EDR2 film measurements agreed with ion chamber results to 2%/2mm accuracy for single-beam fluence map verifications and to 5%/2mm for transverse plane measurements of complete plan dose distributions. The same system was used to quantitatively optimize the radiation field offset and MLC transmission beam modeling parameters for Varian MLCs. While scalar dose comparison metrics can work well for optimization purposes, the influence of external parameters on the dose discrepancies must be minimized. The ability of 2D verifications to detect delivery errors was tested with simulated data. The dosimetric characteristics of delivery errors were compared to patient-specific clinical IMRT verifications. For the clinical verifications, the NAT index and percent of pixels failing the gamma index were exponentially distributed and dependent upon the measurement phantom but not the treatment site. Delivery errors affecting all beams in the treatment plan were flagged by the NAT index, although delivery errors impacting only one beam could not be differentiated from routine clinical verification discrepancies. Clinical use of this system will flag outliers, allow physicists to examine their causes, and perhaps improve the level of agreement between radiation dose distribution measurements and calculations. The principles used to design and evaluate this system are extensible to future multidimensional dose measurements and comparisons. ^

The effects of proteasome inhibition in chronic lymphocytic leukemia and prostate cancer

The use of proteasome inhibitors in cancer has received much attention with the recent FDA approval of bortezomib (Velcade/PS-341). However, in the chronic lymphocytic leukemia (CLL) clinical trial, bortezomib was not as effective as it was in vitro. Accordingly, results in prostate cancer were not remarkable, although regression of lymphadenopathy was observed. This response was also seen in CLL. ^ The proteasome degrades ∼80% of intracellular proteins. Although specific pathways affected by proteasome inhibitors are known, there are still unidentified mechanisms by which they induce apoptosis. The efficacy and mechanism of action of the reversible proteasome inhibitor bortezomib were compared to the novel irreversible inhibitor NPI-0052 in this study, and their mechanisms of action in CLL and prostate cancer were examined. ^ NPI-0052 inhibited proteasome activity and induced apoptosis with more rapid kinetics than bortezomib in CLL. Inhibition of proteasome activity with NPI-0052 was also more durable. Interestingly, bortezomib is cleared from the serum within 15min, which is insufficient time for bortezomib to effectively inhibit the proteasome. However, only 5min exposure was needed for NPI-0052 to produce maximal proteasome inhibition. The data suggest that bortezomib's slow kinetics and reversible nature limit its potential in vivo and the use of NPI-0052 should be considered. ^ In examining the mechanism(s) by which bortezomib and NPI-0052 induce apoptosis in CLL, both were found to elicit the ER stress pathway. A stromal cell co-culture system prevented apoptosis induced by both proteasome inhibitors, suggesting that if such factors in vivo were responsible for reducing bortezomib's efficacy, NPI-0052 would not prove useful either. Finally, Lyn, a Src family kinase (SFK), was decreased in response to bortezomib and NPI-0052 and correlated with apoptosis induction in CLL and prostate cancer. Both proteasome inhibitors specifically targeted Lyn rather than SFKs in general. ^ SFKs are overexpressed in cancer and involved in cell signaling, survival, and metastasis. In prostate cancer cells, both proteasome inhibition and Lyn-silencing significantly inhibited migration. Preliminary evidence also suggested that Lyn downregulation decreases invasion potential. Together, these data suggest that proteasome inhibitors are potential candidates for anti-metastasic therapy and further investigation is warranted for the use of Lyn-targeted therapy to treat metastases. ^

Metastatic lung cancer in a new mouse model inheriting p53 and latent K-ras mutations

Lung cancer is a devastating disease with very poor prognosis. The design of better treatments for patients would be greatly aided by mouse models that closely resemble the human disease. The most common type of human lung cancer is adenocarcinoma with frequent metastasis. Unfortunately, current models for this tumor are inadequate due to the absence of metastasis. Based on the molecular findings in human lung cancer and metastatic potential of osteosarcomas in mutant p53 mouse models, I hypothesized that mice with both K-ras and p53 missense mutations might develop metastatic lung adenocarcinomas. Therefore, I incorporated both K-rasLA1 and p53RI72HΔg alleles into mouse lung cells to establish a more faithful model for human lung adenocarcinoma and for translational and mechanistic studies. Mice with both mutations ( K-rasLA1/+ p53R172HΔg/+) developed advanced lung adenocarcinomas with similar histopathology to human tumors. These lung adenocarcinomas were highly aggressive and metastasized to multiple intrathoracic and extrathoracic sites in a pattern similar to that seen in lung cancer patients. This mouse model also showed gender differences in cancer related death and developed pleural mesotheliomas in 23.2% of them. In a preclinical study, the new drug Erlotinib (Tarceva) decreased the number and size of lung lesions in this model. These data demonstrate that this mouse model most closely mimics human metastatic lung adenocarcinoma and provides an invaluable system for translational studies. ^ To screen for important genes for metastasis, gene expression profiles of primary lung adenocarcinomas and metastases were analyzed. Microarray data showed that these two groups were segregated in gene expression and had 79 highly differentially expressed genes (more than 2.5 fold changes and p<0.001). Microarray data of Bub1b, Vimentin and CCAM1 were validated in tumors by quantitative real-time PCR (QPCR). Bub1b , a mitotic checkpoint gene, was overexpressed in metastases and this correlated with more chromosomal abnormalities in metastatic cells. Vimentin, a marker of epithelial-mesenchymal transition (EMT), was also highly expressed in metastases. Interestingly, Twist, a key EMT inducer, was also highly upregulated in metastases by QPCR, and this significantly correlated with the overexpression of Vimentin in the same tumors. These data suggest EMT occurs in lung adenocarcinomas and is a key mechanism for the development of metastasis in K-ras LA1/+ p53R172HΔg/+ mice. Thus, this mouse model provides a unique system to further probe the molecular basis of metastatic lung cancer.^

High-resolution microarray analysis of chromosome 20q in human colon cancer metastasis model systems

Amplification of human chromosome 20q DNA is the most frequently occurring chromosomal abnormality detected in sporadic colorectal carcinomas and shows significant correlation with liver metastases. Through comprehensive high-resolution microarray comparative genomic hybridization and microarray gene expression profiling, we have characterized chromosome 20q amplicon genes associated with human colorectal cancer metastasis in two in vitro metastasis model systems. The results revealed increasing complexity of the 20q genomic profile from the primary tumor-derived cell lines to the lymph node and liver metastasis derived cell lines. Expression analysis of chromosome 20q revealed a subset of over expressed genes residing within the regions of genomic copy number gain in all the tumor cell lines, suggesting these are Chromosome 20q copy number responsive genes. Bases on their preferential expression levels in the model system cell lines and known biological function, four of the over expressed genes mapping to the common intervals of genomic copy gain were considered the most promising candidate colorectal metastasis-associated genes. Validation of genomic copy number and expression array data was carried out on these genes, with one gene, DNMT3B, standing out as expressed at a relatively higher levels in the metastasis-derived cell lines compared with their primary-derived counterparts in both the models systems analyzed. The data provide evidence for the role of chromosome 20q genes with low copy gain and elevated expression in the clonal evolution of metastatic cells and suggests that such genes may serve as early biomarkers of metastatic potential. The data also support the utility of the combined microarray comparative genomic hybridization and expression array analysis for identifying copy number responsive genes in areas of low DNA copy gain in cancer cells. ^

Proton therapy versus intensity modulated x-ray therapy in the treatment of prostate cancer: Estimating secondary cancer risks

External beam radiation therapy is used to treat nearly half of the more than 200,000 new cases of prostate cancer diagnosed in the United States each year. During a radiation therapy treatment, healthy tissues in the path of the therapeutic beam are exposed to high doses. In addition, the whole body is exposed to a low-dose bath of unwanted scatter radiation from the pelvis and leakage radiation from the treatment unit. As a result, survivors of radiation therapy for prostate cancer face an elevated risk of developing a radiogenic second cancer. Recently, proton therapy has been shown to reduce the dose delivered by the therapeutic beam to normal tissues during treatment compared to intensity modulated x-ray therapy (IMXT, the current standard of care). However, the magnitude of stray radiation doses from proton therapy, and their impact on this incidence of radiogenic second cancers, was not known. ^ The risk of a radiogenic second cancer following proton therapy for prostate cancer relative to IMXT was determined for 3 patients of large, median, and small anatomical stature. Doses delivered to healthy tissues from the therapeutic beam were obtained from treatment planning system calculations. Stray doses from IMXT were taken from the literature, while stray doses from proton therapy were simulated using a Monte Carlo model of a passive scattering treatment unit and an anthropomorphic phantom. Baseline risk models were taken from the Biological Effects of Ionizing Radiation VII report. A sensitivity analysis was conducted to characterize the uncertainty of risk calculations to uncertainties in the risk model, the relative biological effectiveness (RBE) of neutrons for carcinogenesis, and inter-patient anatomical variations. ^ The risk projections revealed that proton therapy carries a lower risk for radiogenic second cancer incidence following prostate irradiation compared to IMXT. The sensitivity analysis revealed that the results of the risk analysis depended only weakly on uncertainties in the risk model and inter-patient variations. Second cancer risks were sensitive to changes in the RBE of neutrons. However, the findings of the study were qualitatively consistent for all patient sizes and risk models considered, and for all neutron RBE values less than 100. ^

Mitochondrial dysfunction leads to NOX activation: A novel mechanism to maintain high glycolysis in cancer cells

Increased glycolysis and oxidative stress are common features of cancer cells. These metabolic alterations are associated with mitochondrial dysfunction and can be caused by mitochondrial DNA (mtDNA) mutations, oncogenic signals, loss of tumor suppressor, and tumor tissue hypoxia. It is well established that mitochondria play central roles in energy metabolism, maintenance of redox balance, and regulation of apoptosis. However, the biochemical and molecular mechanisms that maintain high glycolysis in cancer cells (the Warburg effect) with mitochondrial dysfunction and oxidative stress remain to be determined. The major goals of this study were to establish a unique experimental system in which the mitochondrial respiratory function can be regulated as desired, and to use this system to investigate the mechanistic link between mitochondrial dysfunction and the Warburg effect along with oxidative stress in cancer cells. To achieve these goals, I have established a tetracycline-inducible system in which a dominant negative form of mitochondrial DNA polymerase y (POLGdn) expression could be regulated by tetracycline; thus controlling mitochondrial respiratory function. Using this cell system, I demonstrated that POLGdn expression resulted in mitochondrial dysfunction through decreasing mtDNA content, depletion of mtDNA encoded mRNA and protein expression. This process was mediated by TFAM proteasome degradation. Mitochondrial dysfunction mediated by POLGdn expression led to a significant increase in cellular glycolysis and oxidative stress. Surprisingly, mitochondrial dysfunction also resulted in increased NAD(P)H oxidase (NOX) enzyme activity, which was shown to be essential for maintaining high glycolysis. Chemical Inhibition of NOX activity by diphenyliodonium (DPI) preferentially impacted the survival of mitochondrial defective cells. The colon cancer HCT116-/- cells that have lost transcriptional regulation of the mitochondrial assembling enzyme SCO2, leading to compromised mitochondrial respiratory function, were found to have increased NOX activity and were highly sensitive to DPI treatment. Ovarian epithelial cells with Ras transformation also exhibited an increase in NOX gene expression and NOX enzyme activity, rendering the cells sensitive to DPI inhibition especially under hypoxic condition. These data together suggest that NOX plays a novel role in maintaining high glycolysis in cancer cells with mitochondrial defects, and that NOX may be a potential target for cancer therapy. ^

Selective elimination of cancer cells by PEITC: Biological basis and therapeutic implications

Toxic side effect is a major problem in cancer chemotherapy. Therefore, identification and development of new agents that can selectively remove cancer with low toxicity to normal cells would have significant clinical impact. Compared to normal cells, cancer cells are under intrinsic stress with elevated reactive oxygen species (ROS) production. My research aimed to exploit this biochemical alteration as a novel basis to develop a selective agent. The goal of my dissertation research was to test the hypothesis that since most cancer cells are under higher oxidative stress than normal cells, compounds which modulate oxidative stress such as pphenylethyl isothiocyanate (PEITC) may preferentially impact cancer cells through ROS-mediated mechanisms and have implications in cancer therapeutics. Using H-RasV1-transformed ovarian cells and their immortalized non-tumorigenic counterparts, I discovered that the transformed cells exhibited increased ROS generation and this intrinsic stress rendered them highly dependent on glutathione antioxidant system to maintain redox balance. Abolishing this system by PEITC through depletion of glutathione and inhibition of GPX activity led to a preferential ROS increase in the transformed cells. The severe ROS accumulation caused oxidative damage to the mitochondria membranes and impaired the membrane integrity leading to massive cell death. In contrast, PEITC caused only a modest increase of ROS insufficient to cause significant cell death in non-transformed cells. Promisingly, PEITC exhibited anticancer activity in vivo by prolonging survival of mice bearing the Ras-transformed ovarian xenograft with minimal toxic side effect. Further study in chronic lymphocytic leukemia (CLL) cells isolated from the blood samples of CLL patients revealed that PEITC not only exhibits promising selectivity against primary CLL cells compared to normal lymphocytes, but it is also effective in removing CLL cells resistant to standard anti-cancer drug Fludarabine. In conclusion, the data implicate that intrinsic oxidative stress in cancer cells could serve as a biochemical basis to develop selective novel anticancer agents such as PEITC, with significant therapeutic implications. ^

Hazardous air pollutants and childhood lymphohematopoietic cancer in Southeast Texas, 1995--2004

Southeast Texas, including Houston, has a large presence of industrial facilities and has been documented to have poorer air quality and significantly higher cancer rates than the remainder of Texas. Given citizens’ concerns in this 4th largest city in the U.S., Mayor Bill White recently partnered with the UT School of Public Health to determine methods to evaluate the health risks of hazardous air pollutants (HAPs). Sexton et al. (2007) published a report that strongly encouraged analytic studies linking these pollutants with health outcomes. In response, we set out to complete the following aims: 1. determine the optimal exposure assessment strategy to assess the association between childhood cancer rates and increased ambient levels of benzene and 1,3-butadiene (in an ecologic setting) and 2. evaluate whether census tracts with the highest levels of benzene or 1,3-butadiene have higher incidence of childhood lymphohematopoietic cancer compared with census tracts with the lowest levels of benzene or 1,3-butadiene, using Poisson regression. The first aim was achieved by evaluating the usefulness of four data sources: geographic information systems (GIS) to identify proximity to point sources of industrial air pollution, industrial emission data from the U.S. EPA’s Toxic Release Inventory (TRI), routine monitoring data from the U.S. EPA Air Quality System (AQS) from 1999-2000 and modeled ambient air levels from the U.S. EPA’s 1999 National Air Toxic Assessment Project (NATA) ASPEN model. Further, once these four data sources were evaluated, we narrowed them down to two: the routine monitoring data from the AQS for the years 1998-2000 and the 1999 U.S. EPA NATA ASPEN modeled data. We applied kriging (spatial interpolation) methodology to the monitoring data and compared the kriged values to the ASPEN modeled data. Our results indicated poor agreement between the two methods. Relative to the U.S. EPA ASPEN modeled estimates, relying on kriging to classify census tracts into exposure groups would have caused a great deal of misclassification. To address the second aim, we additionally obtained childhood lymphohematopoietic cancer data for 1995-2004 from the Texas Cancer Registry. The U.S. EPA ASPEN modeled data were used to estimate ambient levels of benzene and 1,3-butadiene in separate Poisson regression analyses. All data were analyzed at the census tract level. We found that census tracts with the highest benzene levels had elevated rates of all leukemia (rate ratio (RR) = 1.37; 95% confidence interval (CI), 1.05-1.78). Among census tracts with the highest 1,3-butadiene levels, we observed RRs of 1.40 (95% CI, 1.07-1.81) for all leukemia. We detected no associations between benzene or 1,3-butadiene levels and childhood lymphoma incidence. This study is the first to examine this association in Harris and surrounding counties in Texas and is among the first to correlate monitored levels of HAPs with childhood lymphohematopoietic cancer incidence, evaluating several analytic methods in an effort to determine the most appropriate approach to test this association. Despite recognized weakness of ecologic analyses, our analysis suggests an association between childhood leukemia and hazardous air pollution.^

Mechanism of methylation gene reactivation in human cancer cells

Epigenetic silencing of tumor suppressor genes by DNA hypermethylation at promoter regions is a common event in carcinogenesis and tumor progression. Abrogation of methylation and reversal of epigenetic silencing is a very potent way in cancer treatment. However, the reactivation mechanisms are poorly understood. In this study, we first developed a cell line model system named YB5, derived from SW48 cancer cell line, which bears one copy of stably integrated EGFP gene on Chromosome 1p31.1 region. The GFP gene expression is transcriptionally silenced due to the hypermethylated promoter CMV. However, the GFP expression can be restored using demethylating agent 5-aza-2' deoxycytidine (DAC), and detected by FACS and fluorescent microscopy. Using this system, we observed the heterogeneous reactivation induced by DAC treatment. After flow sorting, GFP negative cells exhibited similar level of incomplete demethylation compared to GFP positive cells on repetitive LINE1 element, tumor suppressor genes such as P16, CDH13, and RASSF1a, and CMV promoter as well. However, the local chromatin of CMV-GFP locus altered to an open structure marked by high H3 lysine 9 acetylation and low H3 lysine 27 tri-methylation in GFP positive cells, while the GFP negative cells retained mostly the original repressive marks. Thus, we concluded that DAC induced DNA hypomethylation alone does not directly determine the level of re-expression, and the resetting of the local chromatin structure under hypomethylation environment is required for gene reactivation. Besides, a lentivirus vector-based shRNA screening was performed using the YB5 system. Although it is the rare chance that vector lands in the neighboring region of GFP, we found that the exogenous vector DNA inserted into the upstream region of GFP gene locus led to the promoter demethylation and reactivated the silenced GFP gene. Thus, epigenetic state can be affected by changing of the adjacent nucleic acid sequences. Further, this hypermethylation silenced system was utilized for epigenetic drug screening. We have found that DAC combined with carboplatin would enhance the GFP% yield and increase expression of other tumor suppressor genes than DAC alone, and this synergistic effect may be related to DNA repair process. In summary, these studies reveal that reversing of methylation silencing requires coordinated alterations of DNA methylation, chromatin structure, and local microenvironment. ^

Treatment discontinuation among breast, colorectal, and prostate cancer patients in Alabama

Introduction. Cancer registries provide information about treatment initiation but not the full course of treatment. In an effort to identify patient reported reasons for discontinuing cancer treatment, patients with prostate, breast, and colorectal cancer were identified from Alabama State Cancer Registry (ASCR) -Alabama Medicare linked database for interview. This study has two specific aims: (1) determine whether the ASCR-Medicare database accurately reflects patients’ treatment experiences in terms of whether they started and completed treatment when compared to patient self-report and (2) determine which patient demographic and health care system factors are related to treatment completion as defined by patient self-report. ^ Methods. The ASCR-Medicare claims dataset supplemented patient interview responses to identify treatment initiation and completion among prostate, breast, and colorectal cancer patients in Alabama from 1999-2003. Kappa statistic was used to test for concordance of treatment initiation and completion between patient self-report and Medicare claims data. Patients who reported not completing treatment were asked questions to ascertain reasons for treatment discontinuation. Logistic regression models were constructed to explore the association of patient and tumor characteristics with discontinuation of radiation and chemotherapy. ^ Results. Overall, there was a fair agreement across all cancer sites about whether one had surgery (Kappa=.382). There was fair agreement between self-report and Medicare claims data for starting radiation treatment (Kappa=.278). For starting chemotherapy there was moderate agreement (Kappa=.414). There was no agreement for completing treatment for radiation and chemotherapy between the self-report and claims data. Patients most often reported doctor’s recommendation (40% for radiation treatment and 21.4% for chemotherapy) and side effects (30% for radiation treatment and 42.8% for chemotherapy) for discontinuing treatment. Females were less likely to complete radiation than males (OR=.24, 95% CI=.11–.50). Stage I patients were more likely to drop radiation treatment than stage III patients (OR=3.34, 95% CI=1.12–9.95). Younger patients were more likely to discontinue chemotherapy than older patients (OR=2.84 95%, CI=1.08–7.69) and breast cancer patients were less likely to discontinue chemotherapy than colorectal patients (OR=.13, 95% CI=.04–.46). ^ Conclusion. This study reveals that patients recall starting treatment more accurately than completing treatment and that there are several demographic and tumor characteristics that influence treatment discontinuation. Providing patients with treatment summaries and survivorship plans can help patients their follow-up care when there are gaps in treatment recall and discontinuation of treatment.^

Hormone therapy and physical activity as predictors of lung cancer risk and survival: The California Teachers Study

Cigarette smoking is responsible for the majority of lung cancer cases worldwide; however, a proportion of never smokers still develop lung cancer over their lifetime, prompting investigation into additional factors that may modify lung cancer incidence, as well as mortality. Although hormone therapy (HT), physical activity (PA), and lung cancer have been previously examined, the associations remain unclear. This study investigated exposure to HT and PA that may modulate underlying mechanisms of lung cancer etiology and progression among women by using existing, de-identified data from the California Teachers Study (CTS).^ The CTS cohort, established in 1995–1996, has 133,479 active and retired female teachers and administrators, recruited through the California State Teachers Retirement System, and followed annually for cancer diagnosis, death, and change of address. Each woman enrolled in the CTS returned a questionnaire covering a wide variety of issues related to cancer risk and women's health, including recent and past HT use and physical activity, as well as active and environmental cigarette smoke exposure. Complete data to assess the associations between HT and lung cancer risk and survival were available for 60,592 postmenopausal women. Between 1995 and 2007, 727 of these women were diagnosed with invasive lung cancer; 441 of these died. Complete data to assess the associations between PA and lung cancer risk and survival were available for 118,513 women. Between 1995 and 2007, 853 of these women were diagnosed with invasive lung cancer; 516 of these died.^ After careful adjustment for smoking habits and other potential confounders, no measure of HT use was associated with lung cancer risk; however, any HT use (vs. no use) was associated with a decrease in lung-cancer-specific mortality. Specifically, among women who only used estrogen (E-only), decreases in lung cancer mortality were seen for recent use, but not for former use; no association was observed for estrogen plus progestin (E+P). Furthermore, among former users of HT, a statistically significant decrease in lung cancer mortality was observed for E-only use within 5 years prior to baseline, but not for E-only use >5 years prior to baseline. Neither long-term recreational PA nor recent recreational PA alone were associated with lung cancer risk; however, among women with a BMI<25 and ever smokers, high long-term moderate+strenuous PA was associated with a decrease in lung cancer risk. Women with non-local disease showed a decrease in lung cancer mortality associated with increasing duration of strenuous long-term activity, and 1.50-3.00 h/wk/y of recent moderate or recent strenuous PA. Long-term moderate PA was associated with decreased lung cancer mortality in never smokers, whereas recent moderate PA was associated with increased lung cancer mortality in current smokers. ^ Placing our findings in the context of the current literature, HT does not appear to be associated with lung cancer risk and previous studies reporting a protective effect of HT use on lung cancer risk may be subject to residual confounding by smoking. Looking at our findings regarding PA overall, the evidence still remains inconclusive regarding whether or not physical activity influence lung cancer risk or mortality. Our results suggest that recreational PA may associated with decreased lung cancer risk among women with BMI<25 and ever smoking-women; however, residual confounding by smoking should be strongly considered. To our knowledge, this is the first study to investigate lifetime recreational PA and lung cancer mortality among women. Our results contribute to the growing body of knowledge regarding non-smoking-related risk factors for lung cancer incidence and mortality among women. Given the potential clinical and interventional significance, further study and validation of these findings is warranted.^

Quality of life, symptom experience, and use of complementary and alternative medicine among women with ovarian cancer

The objectives of this dissertation were to determine the quality of life in women with ovarian cancer and the association of their physical and emotional well-being with the number of symptoms, duration of symptoms, and the scores of common symptoms of ovarian cancer; to study the prevalence of complementary and alternative medicine techniques for symptom relief and its association with the number of symptoms, age, education, insurance, comorbidity, and satisfaction with medical care they received, and their pre-diagnostic experience of symptoms.^ This study was based on a secondary data analysis of a study of early detection of ovarian cancer. A sample of 139 women with ovarian cancer was recruited and was administered a questionnaire comprised of questions on their quality of life, their symptoms and what they did about the symptoms, whether they used any complementary and alternative medicine techniques, and other medical conditions they had. Out of this sample, 53 patients underwent in-depth interviews relating to their symptoms before the diagnosis and their experiences with the health care system leading to the ovarian cancer diagnosis. ^ In article #1, ovarian cancer patients were observed to have significantly poorer quality of life on all subscales and summary scores except pain, compared to that of the general population of US women. Physical well-being scores were negatively associated with the number of symptoms before diagnosis and a significant negative association of comorbidity index was observed with physical well-being. Higher education and increase in time since diagnosis was found to have better physical scores. Emotional well-being scores showed marginally significant associations with number of symptoms and bloating. ^ In article #2, a thematic content analysis of the ovarian cancer patients’ interviews revealed that on recognition of their symptoms women first assumed their symptoms to be a normal transient occurrence due to a pre-existing disease condition, or due to some other disease. A series of misattributions of their symptoms on their and their doctors’ part impacted their health care seeking.In article #3, a significantly greater likelihood of CAM use with an increase in the number of symptoms was observed.^ Based on the foregoing results, it is important to educate women on possible signs of ovarian cancer and also to educate doctors about the results of current research regarding ovarian cancer diagnosis. This will help to avoid a delay in getting a diagnosis and improve women’s quality of life. It emphasizes the diagnosis of ovarian cancer in earlier stages by more sensitive screening techniques. This study emphasizes the importance of consideration of comorbidity in any quality of life research. Additionally, educating women in the safe use of CAM techniques carries immense significance because the efficacy and safety of many of the currently advertized CAM products has not been scientifically validated. Further research is needed to confirm the findings of this study. ^

Bayesian and survival model for tumor relapse status and disease-specific survival, with applications to breast cancer

Breast cancer is the most common non-skin cancer and the second leading cause of cancer-related death in women in the United States. Studies on ipsilateral breast tumor relapse (IBTR) status and disease-specific survival will help guide clinic treatment and predict patient prognosis.^ After breast conservation therapy, patients with breast cancer may experience breast tumor relapse. This relapse is classified into two distinct types: true local recurrence (TR) and new ipsilateral primary tumor (NP). However, the methods used to classify the relapse types are imperfect and are prone to misclassification. In addition, some observed survival data (e.g., time to relapse and time from relapse to death)are strongly correlated with relapse types. The first part of this dissertation presents a Bayesian approach to (1) modeling the potentially misclassified relapse status and the correlated survival information, (2) estimating the sensitivity and specificity of the diagnostic methods, and (3) quantify the covariate effects on event probabilities. A shared frailty was used to account for the within-subject correlation between survival times. The inference was conducted using a Bayesian framework via Markov Chain Monte Carlo simulation implemented in softwareWinBUGS. Simulation was used to validate the Bayesian method and assess its frequentist properties. The new model has two important innovations: (1) it utilizes the additional survival times correlated with the relapse status to improve the parameter estimation, and (2) it provides tools to address the correlation between the two diagnostic methods conditional to the true relapse types.^ Prediction of patients at highest risk for IBTR after local excision of ductal carcinoma in situ (DCIS) remains a clinical concern. The goals of the second part of this dissertation were to evaluate a published nomogram from Memorial Sloan-Kettering Cancer Center, to determine the risk of IBTR in patients with DCIS treated with local excision, and to determine whether there is a subset of patients at low risk of IBTR. Patients who had undergone local excision from 1990 through 2007 at MD Anderson Cancer Center with a final diagnosis of DCIS (n=794) were included in this part. Clinicopathologic factors and the performance of the Memorial Sloan-Kettering Cancer Center nomogram for prediction of IBTR were assessed for 734 patients with complete data. Nomogram for prediction of 5- and 10-year IBTR probabilities were found to demonstrate imperfect calibration and discrimination, with an area under the receiver operating characteristic curve of .63 and a concordance index of .63. In conclusion, predictive models for IBTR in DCIS patients treated with local excision are imperfect. Our current ability to accurately predict recurrence based on clinical parameters is limited.^ The American Joint Committee on Cancer (AJCC) staging of breast cancer is widely used to determine prognosis, yet survival within each AJCC stage shows wide variation and remains unpredictable. For the third part of this dissertation, biologic markers were hypothesized to be responsible for some of this variation, and the addition of biologic markers to current AJCC staging were examined for possibly provide improved prognostication. The initial cohort included patients treated with surgery as first intervention at MDACC from 1997 to 2006. Cox proportional hazards models were used to create prognostic scoring systems. AJCC pathologic staging parameters and biologic tumor markers were investigated to devise the scoring systems. Surveillance Epidemiology and End Results (SEER) data was used as the external cohort to validate the scoring systems. Binary indicators for pathologic stage (PS), estrogen receptor status (E), and tumor grade (G) were summed to create PS+EG scoring systems devised to predict 5-year patient outcomes. These scoring systems facilitated separation of the study population into more refined subgroups than the current AJCC staging system. The ability of the PS+EG score to stratify outcomes was confirmed in both internal and external validation cohorts. The current study proposes and validates a new staging system by incorporating tumor grade and ER status into current AJCC staging. We recommend that biologic markers be incorporating into revised versions of the AJCC staging system for patients receiving surgery as the first intervention.^ Chapter 1 focuses on developing a Bayesian method to solve misclassified relapse status and application to breast cancer data. Chapter 2 focuses on evaluation of a breast cancer nomogram for predicting risk of IBTR in patients with DCIS after local excision gives the statement of the problem in the clinical research. Chapter 3 focuses on validation of a novel staging system for disease-specific survival in patients with breast cancer treated with surgery as the first intervention. ^

Increasing awareness of colorectal cancer screening through targeted exam room based video messages

Colorectal cancer (CRC) is the third largest cause of cancer death in the United States. While the disease burden is high, there are proven methods to screen for CRC and detect it at a stage that is amenable to cure. Patients with low health literacy have difficulty navigating the health care system and are at increased risk to not receive preventive care services such as colorectal cancer screening (CRCS). To address this need, an exam-room based video was developed to be played for patients in the privacy of the exam room, while they are waiting to be seen by their medical provider. In roughly 2 minutes, the video informs the patient about CRC and CRCS and how they can successfully complete CRCS. One of the key barriers to completing CRCS is the need to increase patients' knowledge and improve attitudes surrounding CRCS. This study examines the impact of the video on patients' knowledge and attitudes about CRC and CRCS in a medically underserved patient population in Houston, Texas. ^ Sixty-one patients presenting for routine medical care were enrolled in the study. Depending on their randomization, the patients either received routine information about CRC and CRCS or they watched the video. We found that the patients who did watch the video did have improvements in their knowledge and improved attitudes about CRC and CRCS. Future studies will be needed to examine whether the video improves the patients' completion of CRCS.^