DW-MRI of the urogenital tract: applications in oncology

Diffusion-weighted magnetic resonance imaging (DW-MRI) appears to hold promise as a non-invasive imaging modality in the detection of early microstructural and functional changes of different organs. DW-MRI is an imaging technique with a high sensitivity for the detection of a large variety of diseases in the urogenital tract. In kidneys, DW-MRI has shown promise for the characterization of solid lesions. Also in focal T1 hyperintense lesions DW-MRI was able to differentiate hemorrhagic cysts from tumours according to the lower apparent diffusion coefficient (ADC) values reported for renal cell carcinomas. Promising results were also published for the detection of prostate cancer. DW-MRI applied in addition to conventional T2-weighted imaging has been found to improve tumour detection. On a 3 T magnetic resonance unit ADC values were reported to be lower for tumours compared with the normal-appearing peripheral zone. The combined approach of T2-weighted imaging and DW-MRI also showed promising results for the detection of recurrent tumour in patients after radiation therapy. DW-MRI may improve the performance of conventional T2-weighted and contrast-enhanced MRI in the preoperative work-up of bladder cancer, as it may help in distinguishing superficial from muscle invasive bladder cancer, which is critical for patient management. Another challenging application of DW-MRI in the urogenital tract is the detection of pelvic lymph node metastases. As the ADC is generally reduced in malignant tumours and increased under inflammatory conditions, reduced ADC values were expected in patients with lymph node metastases.

Association of urethral toxicity with dose exposure in combined high-dose-rate brachytherapy and intensity-modulated radiation therapy in intermediate- and high-risk prostate cancer

INTRODUCTION: To report acute and late toxicities in patients with intermediate- and high-risk prostate cancer treated with combined high-dose-rate brachytherapy (HDR-B) and intensity-modulated radiation therapy (IMRT). MATERIALS AND METHODS: From March 2003 to September 2005, 64 men were treated with a single implant HDR-B with 21 Gy given in three fractions, followed by 50 Gy IMRT along with organ tracking. Median age was 66.1 years, and risk of recurrence was intermediate in 47% of the patients or high in 53% of the patients. Androgen deprivation therapy was received by 69% of the patients. Toxicity was scored according to the CTCAE version 3.0. Median follow-up was 3.1 years. RESULTS: Acute grade 3 genitourinary (GU) toxicity was observed in 7.8% of the patients, and late grades 3 and 4 GU toxicity was observed in 10.9% and 1.6% of the patients. Acute grade 3 gastrointestinal (GI) toxicity was experienced by 1.6% of the patients, and late grade 3 GI toxicity was absent. The urethral V(120) (urethral volume receiving > or =120% of the prescribed HDR-B dose) was associated with acute (P=.047) and late > or = grade 2 GU toxicities (P=.049). CONCLUSIONS: Late grades 3 and 4GU toxicity occurred in 10.9% and 1.6% of the patients after HDR-B followed by IMRT in association with the irradiated urethral volume. The impact of V(120) on GU toxicity should be validated in further studies.

Synchrotron microbeam radiation therapy induces hypoxia in intracerebral gliosarcoma but not in the normal brain

PURPOSE Synchrotron microbeam radiation therapy (MRT) is an innovative irradiation modality based on spatial fractionation of a high-dose X-ray beam into lattices of microbeams. The increase in lifespan of brain tumor-bearing rats is associated with vascular damage but the physiological consequences of MRT on blood vessels have not been described. In this manuscript, we evaluate the oxygenation changes induced by MRT in an intracerebral 9L gliosarcoma model. METHODS Tissue responses to MRT (two orthogonal arrays (2 × 400Gy)) were studied using magnetic resonance-based measurements of local blood oxygen saturation (MR_SO2) and quantitative immunohistology of RECA-1, Type-IV collagen and GLUT-1, marker of hypoxia. RESULTS In tumors, MR_SO2 decreased by a factor of 2 in tumor between day 8 and day 45 after MRT. This correlated with tumor vascular remodeling, i.e. decrease in vessel density, increases in half-vessel distances (×5) and GLUT-1 immunoreactivity. Conversely, MRT did not change normal brain MR_SO2, although vessel inter-distances increased slightly. CONCLUSION We provide new evidence for the differential effect of MRT on tumor vasculature, an effect that leads to tumor hypoxia. As hypothesized formerly, the vasculature of the normal brain exposed to MRT remains sufficiently perfused to prevent any hypoxia.

Tumors in the contralateral breast following radiation therapy for breast cancer

The proportional distribution of independent malignant tumors in the contralateral breast following treatment for breast cancer was investigated to assess the influence of scattered radiation as a cause of these tumors. In a population of 172 patients the proportion of contralateral tumors in each quadrant and the center (the nipple-areolar complex) was compared with the expected, or natural, distribution found in the general population, in the absence of radiation. The observed/expected ratio for contralateral tumors was 1.43 for the upper-inner quadrant; 0.97, lower-inner quadrant; 1.51, center; 0.76, upper-outer quadrant; and 0.64, lower-outer quadrant. In each quadrant, except the lower-inner, the observed/expected ratio differed from 1.00 with statistical significance at the 5% level (one-tail). The same analysis, stratified by age and menopausal status, showed a similar shift of tumors, with more than expected in the inner quadrants and center and less than expected in the outer quadrants, although the results did not show statistical significance at the 5% level for all strata. For each patient the mean absorbed radiation dose for each quadrant and center of the breast was estimated, based on measurements in a tissue-equivalent phantom. Among patients the doses ranged from 0.5 to 8 Gy; within individuals, doses to the inner quadrants typically were a factor of three times higher than doses to the outer quadrants. The results suggest that radiation may be a risk factor for contralateral breast tumors and warrants further investigation. ^

Relationship between survival and increased radiation dose to subventricular zone in glioblastoma is controversial.

To test the hypothesis on prolonged survival in glioblastoma cases with increased subventricular zone (SVZ) radiation dose. Sixty glioblastoma cases were previously treated with adjuvant radiotherapy and Temozolamide. Ipsilateral, contralateral and bilateral SVZs were contoured and their doses were retrospectively evaluated. Median follow-up, progression free survival (PFS) and overall survival (OS) were 24.5, 8.5 and 19.3 months respectively. Log-rank tests showed a statistically significant correlation between contralateral SVZ (cSVZ) dose > 59.2 Gy (75th percentile) and poor median PFS (10.37 [95% CI 8.37-13.53] vs 7.1 [95% CI 3.5-8.97] months, p = 0.009). cSVZ dose > 59.2 Gy was associated with poor OS in the subgroup with subtotal resection/biopsy (HR: 4.83 [95% CI 1.71-13.97], p = 0.004). High ipsilateral SVZ dose of > 62.25 Gy (75th percentile) was associated with poor PFS in both subgroups of high performance status (HR: 2.58 [95% CI 1.03-6.05], p = 0.044) and SVZ without tumoral contact (HR: 10.57 [95% CI 2.04-49], p = 0.008). The effect of high cSVZ dose on PFS lost its statistical significance in multivariate Cox regression analysis. We report contradictory results compared to previous publications. Changing the clinical practice based on retrospective studies which even do not indicate consistent results among each other will be dangerous. We need carefully designed prospective randomized studies to evaluate any impact of radiation to SVZ in glioblastoma.

Acute Toxicity and Quality of Life After Dose-Intensified Salvage Radiation Therapy for Biochemically Recurrent Prostate Cancer After Prostatectomy: First Results of the Randomized Trial SAKK 09/10

PURPOSE Patients with biochemical failure (BF) after radical prostatectomy may benefit from dose-intensified salvage radiation therapy (SRT) of the prostate bed. We performed a randomized phase III trial assessing dose intensification. PATIENTS AND METHODS Patients with BF but without evidence of macroscopic disease were randomly assigned to either 64 or 70 Gy. Three-dimensional conformal radiation therapy or intensity-modulated radiation therapy/rotational techniques were used. The primary end point was freedom from BF. Secondary end points were acute toxicity according to the National Cancer Institute Common Terminology Criteria for Adverse Events (version 4.0) and quality of life (QoL) according to the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaires C30 and PR25. RESULTS Three hundred fifty patients were enrolled between February 2011 and April 2014. Three patients withdrew informed consent, and three patients were not eligible, resulting in 344 patients age 48 to 75 years in the safety population. Thirty patients (8.7%) had grade 2 and two patients (0.6%) had grade 3 genitourinary (GU) baseline symptoms. Acute grade 2 and 3 GU toxicity was observed in 22 patients (13.0%) and one patient (0.6%), respectively, with 64 Gy and in 29 patients (16.6%) and three patients (1.7%), respectively, with 70 Gy (P = .2). Baseline grade 2 GI toxicity was observed in one patient (0.6%). Acute grade 2 and 3 GI toxicity was observed in 27 patients (16.0%) and one patient (0.6%), respectively, with 64 Gy, and in 27 patients (15.4%) and four patients (2.3%), respectively, with 70 Gy (P = .8). Changes in early QoL were minor. Patients receiving 70 Gy reported a more pronounced and clinically relevant worsening in urinary symptoms (mean difference in change score between arms, 3.6; P = .02). CONCLUSION Dose-intensified SRT was associated with low rates of acute grade 2 and 3 GU and GI toxicity. The impact of dose-intensified SRT on QoL was minor, except for a significantly greater worsening in urinary symptoms.

The ROAM/EORTC-1308 trial: Radiation versus Observation following surgical resection of Atypical Meningioma: study protocol for a randomised controlled trial.

BACKGROUND Atypical meningiomas are an intermediate grade brain tumour with a recurrence rate of 39-58 %. It is not known whether early adjuvant radiotherapy reduces the risk of tumour recurrence and whether the potential side-effects are justified. An alternative management strategy is to perform active monitoring with magnetic resonance imaging (MRI) and to treat at recurrence. There are no randomised controlled trials comparing these two approaches. METHODS/DESIGN A total of 190 patients will be recruited from neurosurgical/neuro-oncology centres across the United Kingdom, Ireland and mainland Europe. Adult patients undergoing gross total resection of intracranial atypical meningioma are eligible. Patients with multiple meningioma, optic nerve sheath meningioma, previous intracranial tumour, previous cranial radiotherapy and neurofibromatosis will be excluded. Informed consent will be obtained from patients. This is a two-stage trial (both stages will run in parallel): Stage 1 (qualitative study) is designed to maximise patient and clinician acceptability, thereby optimising recruitment and retention. Patients wishing to continue will proceed to randomisation. Stage 2 (randomisation) patients will be randomised to receive either early adjuvant radiotherapy for 6 weeks (60 Gy in 30 fractions) or active monitoring. The primary outcome measure is time to MRI evidence of tumour recurrence (progression-free survival (PFS)). Secondary outcome measures include assessing the toxicity of the radiotherapy, the quality of life, neurocognitive function, time to second line treatment, time to death (overall survival (OS)) and incremental cost per quality-adjusted life year (QALY) gained. DISCUSSION ROAM/EORTC-1308 is the first multi-centre randomised controlled trial designed to determine whether early adjuvant radiotherapy reduces the risk of tumour recurrence following complete surgical resection of atypical meningioma. The results of this study will be used to inform current neurosurgery and neuro-oncology practice worldwide. TRIAL REGISTRATION ISRCTN71502099 on 19 May 2014.

Primary lung cancer after breast cancer: The role of radiation therapy and cigarette smoking

The magnitude of the interaction between cigarette smoking, radiation therapy, and primary lung cancer after breast cancer remains unresolved. This case control study further examines the main and joint effects of cigarette smoking and radiation therapy (XRT) among breast cancer patients who subsequently developed primary lung cancer, at The University of Texas M. D. Anderson Cancer Center (MDACC) in Houston, Texas. Cases (n = 280) were women diagnosed with primary lung cancer between 1955 and 1970, between 30–89 years of age, who had a prior history of breast cancer, and were U.S. residents. Controls (n = 300) were randomly selected from 37,000 breast cancer patients at MDACC and frequency matched to cases on age at diagnosis (in 5-year strata), ethnicity, year of breast cancer diagnosis (in 5-year strata), and had survived at least as long as the time interval for lung cancer diagnosis in the cases. Stratified analysis and unconditional logistic regression modeling were used to calculate the main and joint effects of cigarette smoking and radiation treatment on lung cancer risk. Medical record review yielded smoking information on 93% of cases and 84% of controls, and among cases 45% received XRT versus 44% of controls. Smoking increased the odds of lung cancer in women who did not receive XRT (OR = 6.0, 95%CI, 3.5–10.1) whereas XRT was not associated with increased odds (OR = 0.5, 95%CI, 0.2–1.1) in women who did not smoke. Overall the odds ratio for both XRT and smoking together compared with neither exposure was 9.00 (9 5% CI, 5.1–15.9). Similarly, when stratifying on laterality of the lung cancer in relation to the breast cancer, and when the time interval between breast and lung cancers was >10 years, there was an increased odds for both smoking and XRT together for lung cancers on the same side as the breast cancer (ipsilateral) (OR = 11.5, 95% CI, 4.9–27.8) and lung cancers on the opposite side of the breast cancer (contralateral) (OR= 9.6, 95% CI, 2.9–0.9). After 20 years the odds for the ipsilateral lung were even more pronounced (OR = 19.2, 95% CI, 4.2–88.4) compared to the contralateral lung (OR = 2.6, 95% CI, 0.2–2.1). In conclusion, smoking was a significant independent risk factor for lung cancer after breast cancer. Moreover, a greater than multiplicative effect was observed with smoking and XRT combined being especially evident after 10 years for both the ipsilateral and contralateral lung and after 20 years for the ipsilateral lung. ^

4HPR-X radiation mechanisms of interactions in non-small cell lung cancer (NSCLC) cells in vitro

Lung cancer is the leading cause of cancer death. However, poor survival using conventional therapies fuel the search for more rational interventions. The objective of this study was to design and implement a 4HPR-radiation interaction model in NSCLC, employing a traditional clinical modality (radiation), a relatively new, therapeutically unexplored agent (4HPR) and rationally combining them based on molecular mechanistic findings pertaining to their interactions. To test the hypothesis that 4HPR sensitizes cells to radiation-induced cell death via G2+M accumulation, we designed a working model consisting of H522 adenocarcinoma cells (p53, K-ras mutated) derived from an NSCLC patient; 4HPR at concentrations up to 10 μM; and X radiation up to 6 Gy generated by a patient-dedicated Phillips RT-250 X ray unit at 250 KV, 15 mA, 1.85 Gy/min. We found that 4HPR produced time- and dose-dependent morphological changes, growth inhibition, and DNA damage-inducing enhancement of reactive oxygen species. A transient G2+M accumulation of cells maximal at 24 h of continuous 4HPR exposure was used for irradiation time scheduling. Our data demonstrated enhanced cell death (both apoptotic and necrotic) in irradiated cells pre-treated with 4HPR versus those with either stressor alone. 4HPR's effect of increased NSCLC cells' radioresponse was confirmed by clonogenic assay. To explore these practical findings from a molecular mechanistic perspective, we further investigated and showed that levels of cyclin B1 and p34cdc2 kinase—both components of the mitosis promoting factor (MPF) regulating the G2/M transition—did not change following 4HPR treatment. Likewise, cdc25C phosphatase was not altered. However, enhanced p34cdc2 phosphorylation on its Thr14Tyr15 residues—indicative of its inactivation and increased expression of MPF negative regulators chk1 and wee1 kinases—were supportive of explaining 4HPR-treated cells' accumulation. Hence, p34cdc2 phosphorylation, chk1, and wee1 warrant further evaluation as potential molecular targets for 4HPR-X radiation combination. In summary, we (1) demonstrated that 4HPR not only induces cell death by itself, but also increases NSCLC cells' subsequent radioresponse, indicative of potential clinical applicability, and (2) for the first time, shed light on deciphering 4HPR-X radiation molecular mechanisms of interaction, including the finding of 4HPR's role as a p34cdc2 inactivator via Thr14Tyr15 phosphorylation. ^

The role of UV radiation in the development of myeloid malignancy in Rag2 knockout mice

Excessive exposure to the UV radiation present in sunlight can lead to the development of skin cancer in humans. Majority of the UV-induced skin tumors in immune-competent mice are highly antigenic in nature. Additionally, they exhibit a high frequency of mutations in the p53 gene, which arise very early in the course of UV radiation and most of them disappear before the development of skin tumors. ^ Initially, this study was to determine whether UV radiation induces skin tumors much earlier in immune deficient Rag2 knockout mice than in immune-competent mice, and if so, compare their antigenic properties and p53 mutation spectra. However, chronic UV irradiation (10 kJ/m2) induced myeloproliferative disease (MPD) as early as 4 weeks in Rag2 knockout mice instead of skin tumors. Conversely, unirradiated Rag2 knockout mice developed MPD at a low frequency, but the frequency increased with the animal's age. Although the UV-irradiated wild type mice (B6129) developed MPD, its frequency was lower and the occurrence much later than the Rag2 knockout mice. ^ This observation led to our new hypothesis that UV irradiation plays a role in the development of MPD in Rag2 knockout mice. After 4 weeks of UV radiation, both histopathology (myeloid:erythroid ratio, number of blast cells) and flow cytometry (mature myeloid, granulocytes and immature cells) demonstrated an increased number of mice affected with the disease in the UV-irradiated Rag2 knockout group than the other groups. ^ We also investigated the role of cytokines and absence of T and B cells in the development of MPD in the Rag2 knockout mice. Results indicated that IL-3 and IL-3Rα chain expression was upregulated in the spleens of the UV-irradiated Rag2 knockout mice (4 weeks). Reconstitution of the Rag2 knockout mice with T and B cells abrogated the UV-accelerated development of MPD. Both histopathology and flow cytometric analysis (mature myeloid cells, granulocytes) showed a decrease in the number of mice affected with the disease in the UV-irradiated, reconstituted group rather than any other group. In summary, this study provides the first experimental evidence that exposure to UV irradiation can lead to the development of MPD in immune deficient mice. ^

Modulation of radiation-induced genetic damage by HCMV: A glioma case-control study

Human cytomegalovirus (HCMV) infection occurs early in life and leads to life-long viral persistence. An association between HCMV infection and malignant gliomas has been reported suggesting that HCMV may play a role in glioma pathogenesis. The reported effects of HCMV on cells suggest that it could facilitate accrual of genotoxic damage. We therefore tested the hypothesis that HCMV infection modifies the sensitivity of cells to genetic damage from environmental insults such as γ-irradiation. Peripheral blood lymphocytes from 110 glioma patients and 100 controls were used to measure the level of both chromosome damage and cell death as endpoints for genetic instability. For each study participant, the extent of baseline, HCMV-, γ-radiation- and both – induced genetic instability was evaluated. Radiation induced a significant increase in aberration frequency over baseline in both cases and controls. Similarly, HCMV induced a significant increase in aberration frequency regardless of the disease status. Interestingly, HCMV induced damage was either equal or higher than that induced by radiation. Infected with HCMV prior to challenge with γ-radiation demonstrated a significant increase in the aberration frequency as compared to baseline, radiation- or HCMV-treated cells. With regards to apoptosis, cases showed a lower percentage of induction following in vitro exposure to γ-radiation and/or HCMV infection. The level of apoptosis was inversely related to the amount of chromosome damage in the cases, but not in the controls. These data indicate that, HCMV infection enhances the sensitivity of PBLs to γ-radiation-induced genetic damage.^

Alterations in the ras oncogene and the p53 tumor suppressor gene in ultraviolet radiation-induced skin carcinogenesis

A rapid increase of the ultraviolet radiation (UVR)-related skin cancer incidence has attracted more and more public attention during the last few decades. Prevention and treatment of UVR-related skin cancer has become an important public health issue in the United States. Recent studies indicate that mutations in ras and/or p53 genes may be involved in UVR-induced skin tumor development but the precise molecular mechanism remains unclear. In this study, alterations of H-ras and p53 genes were investigated in different stages of carcinogenesis in a chronic UVR (solar simulator) exposure-induced Sencar mouse skin carcinogenesis model in order to clarify the role of the alterations of these genes during the skin carcinogenesis process and to further understand the mechanisms by which UVR causes skin cancer.^ Positive ras-p21 staining in cell membranes and cytosol were detected in 18/33 (55%) of squamous cell carcinomas (SCCs), but were not detected in UV-exposed skin, papillomas, or spindle cell tumors (SCTs). Positive staining of the malignant progression marker K13 was found in 17/33 (52%) of SCCs only. A significant positive correlation was observed between the K13 and the ras-p21 expression. Polymerase chain reaction (PCR)-based single strand conformation polymorphism (SSCP) analysis and gene sequencing analysis revealed three point mutations, one (codon 56) in UV-exposed non-tumor bearing skin and the other two (codons 21 and 13) in SCCs. No UV-specific mutation patterns were found.^ Positive p53 nuclear staining was found in 10/37 (27%) of SCCs and 12/24 (50%) of SCTs, but was not detected in normal skin or papillomas. PCR-based SSCP and sequencing analysis revealed eight point mutations in exons 5 and 6 (four in SCTs, two in SCCs, and two in UV-exposed skin) including six C-T or C-A transitions. Four of the mutations occurred at a dipyrimidine (CC) sequence. The pattern of the mutations indicated that the mutagenic lesions were induced by UVR.^ These results indicate that overexpression of ras-p21 in conjunction with aberrant expression of K13 occurred frequently in UVR-induced SCCs in Sencar mouse skin. The point mutation in the H-ras gene appeared to be a rare event in UVR skin carcinogenesis and may not be responsible for overexpression of ras-p21. UVR-induced P53 gene alteration is a frequent event in UVR-induced SCCs and later stage SCT tumors in Sencar mice skin, suggesting the p53 gene mutation plays an important role in skin tumor malignant progression. ^

The role of p53 in skin cancer induction by UV radiation and as a potential tumor antigen in UV-induced murine skin tumors

Carcinoma of the skin is the most common type of human cancer in the United States. Ultraviolet radiation (UVR) present in the sunlight is thought to be the major carcinogen responsible for induction of skin cancer. In UV-associated skin carcinogenesis, mutations in p53 are not only present with very high frequency, but occur early in the course of tumor development. In addition, UV-induced skin tumors in mice exhibit unique immunological characteristics. They are highly antigenic and express both individually-specific tumor transplantation antigens recognized by effector T cells and the UV-associated common antigen recognized by UV-induced suppressor T cells. ^ To examine the hypothesis that p53 plays a critical role in preventing skin cancer induction by UVR, mice constitutively lacking one or two functional p53 alleles were compared to wild-type mice for their susceptibility to UV carcinogenesis. Both p53 +/– and –/– mice showed greater susceptibility to skin cancer induction than wild-type mice, and –/– mice were the most susceptible, Accelerated tumor development in the p53 +/– mice was not associated with loss of the remaining wild-type allele of p53 , but in many cases was associated with UV-induced mutations in p53. Our studies clearly demonstrate the essential role of p53 in protection against UV carcinogenesis, particularly in the eye and epidermis. ^ The role of p53 in the antigenicity of UV-induced murine skin tumors was also addressed. Primary UV-induced tumors from p53 –/–, +/– and +/+ mice were transplanted into both normal and immunosuppressed mice, and rates of tumor rejection were compared. Tumors from mice with only one or no functional p53 alleles were less antigenic than those from mice with two functional p53 alleles. Moreover, tumors with no functional p53 also failed to grow well in chronically UV-irradiated mice. These results indicate that p53 contributes to the strong antigenicity of UV-induced murine skin tumors, and suggest that it may play a critical role in expression of the UV-associated common antigen recognized by suppressor T cells. ^ In this study we also monitored the effect of UVR on the development of lymphoid malignancies in p53 deficient mice. The incidence of lymphoid malignancies in UV-irradiated p53 +/– mice was drastically enhanced compared to that in unirradiated counterparts. The immune responses of the mice were identical and were suppressed to the same extent by UV irradiation regardless of the p53 genotype. These data provide the first experimental evidence that exposure to UVR can contribute to the development of lymphoid neoplasms in genetically susceptible hosts. ^

Hybrid Monte Carlo dose algorithm for low energy X-rays intraoperative radiation therapy

Low energy X-rays Intra-Operative Radiation Therapy (XIORT) treatment delivered during surgery (ex: INTRABEAM, Carl Zeiss, and Axxent, Xoft) can benefit from accurate and fast dose prediction in a patient 3D volume.

Validation of a phase space determination algorithm for intraoperative radiation therapy

Monte-Carlo (MC) methods are a valuable tool for dosimetry in radiotherapy, including Intra-Operative Electron Radiotherapy (IOERT), since effects such as inhomogeneities or beam hardening may be realistically reproduced.