Cigarette smoking and endometrial cancer risk: the modifying effect of obesity.

The objective of this study was to evaluate the association between cigarette smoking and endometrial cancer risk by investigating potential modifying effects of menopausal status, obesity, and exogenous hormones. We pooled data from three case-control studies with the same study design conducted in Italy and Switzerland between 1982 and 2006. Overall, 1446 incident endometrial cancers and 4076 hospital controls were enrolled. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression models, conditioned on study and centre, and adjusted for age, period of interview, age at menarche, parity, and body mass index. In comparison with never smokers, current smokers showed reduced endometrial cancer risk (OR: 0.80; 95% CI: 0.66-0.96), with a 28% decrease in risk for smoking >/=20 cigarettes/day. The association did not vary according to menopausal status, oral contraceptive use, or hormone replacement therapy. However, heterogeneity emerged according to body mass index among postmenopausal women, with obese women showing the greatest risk reduction for current smoking (OR: 0.47; 95% CI: 0.27-0.81). In postmenopausal women, obesity turned out to be an important modifier of the association between cigarette smoking and the risk of endometrial cancer. This finding calls for caution in interpreting the favorable effects of cigarette smoking, considering the toxic and carcinogenic effects of tobacco.

CPT-11 and concomitant hyperfractionated accelerated radiotherapy induce efficient local control in rectal cancer patients: results from a phase II.

Patients with rectal cancer are at high risk of disease recurrence despite neoadjuvant radiochemotherapy with 5-Fluorouracil (5FU), a regimen that is now widely applied. In order to develop a regimen with increased antitumour activity, we previously established the recommended dose of neoadjuvant CPT-11 (three times weekly 90 mg m(-2)) concomitant to hyperfractionated accelerated radiotherapy (HART) followed by surgery within 1 week. Thirty-three patients (20 men) with a locally advanced adenocarcinoma of the rectum were enrolled in this prospective phase II trial (1 cT2, 29 cT3, 3 cT4 and 21 cN+). Median age was 60 years (range 43-75 years). All patients received all three injections of CPT-11 and all but two patients completed radiotherapy as planned. Surgery with total mesorectal excision (TME) was performed within 1 week (range 2-15 days). The preoperative chemoradiotherapy was overall well tolerated, 24% of the patients experienced grade 3 diarrhoea that was easily manageable. At a median follow-up of 2 years no local recurrence occurred, however, nine patients developed distant metastases. The 2-year disease-free survival was 66% (95% confidence interval 0.48-0.83). Neoadjuvant CPT-11 and HART allow for excellent local control; however, distant relapse remains a concern in this patient population.

A model of cellular dosimetry for macroscopic tumors in radiopharmaceutical therapy.

PURPOSE: In the radiopharmaceutical therapy approach to the fight against cancer, in particular when it comes to translating laboratory results to the clinical setting, modeling has served as an invaluable tool for guidance and for understanding the processes operating at the cellular level and how these relate to macroscopic observables. Tumor control probability (TCP) is the dosimetric end point quantity of choice which relates to experimental and clinical data: it requires knowledge of individual cellular absorbed doses since it depends on the assessment of the treatment's ability to kill each and every cell. Macroscopic tumors, seen in both clinical and experimental studies, contain too many cells to be modeled individually in Monte Carlo simulation; yet, in particular for low ratios of decays to cells, a cell-based model that does not smooth away statistical considerations associated with low activity is a necessity. The authors present here an adaptation of the simple sphere-based model from which cellular level dosimetry for macroscopic tumors and their end point quantities, such as TCP, may be extrapolated more reliably. METHODS: Ten homogenous spheres representing tumors of different sizes were constructed in GEANT4. The radionuclide 131I was randomly allowed to decay for each model size and for seven different ratios of number of decays to number of cells, N(r): 1000, 500, 200, 100, 50, 20, and 10 decays per cell. The deposited energy was collected in radial bins and divided by the bin mass to obtain the average bin absorbed dose. To simulate a cellular model, the number of cells present in each bin was calculated and an absorbed dose attributed to each cell equal to the bin average absorbed dose with a randomly determined adjustment based on a Gaussian probability distribution with a width equal to the statistical uncertainty consistent with the ratio of decays to cells, i.e., equal to Nr-1/2. From dose volume histograms the surviving fraction of cells, equivalent uniform dose (EUD), and TCP for the different scenarios were calculated. Comparably sized spherical models containing individual spherical cells (15 microm diameter) in hexagonal lattices were constructed, and Monte Carlo simulations were executed for all the same previous scenarios. The dosimetric quantities were calculated and compared to the adjusted simple sphere model results. The model was then applied to the Bortezomib-induced enzyme-targeted radiotherapy (BETR) strategy of targeting Epstein-Barr virus (EBV)-expressing cancers. RESULTS: The TCP values were comparable to within 2% between the adjusted simple sphere and full cellular models. Additionally, models were generated for a nonuniform distribution of activity, and results were compared between the adjusted spherical and cellular models with similar comparability. The TCP values from the experimental macroscopic tumor results were consistent with the experimental observations for BETR-treated 1 g EBV-expressing lymphoma tumors in mice. CONCLUSIONS: The adjusted spherical model presented here provides more accurate TCP values than simple spheres, on par with full cellular Monte Carlo simulations while maintaining the simplicity of the simple sphere model. This model provides a basis for complementing and understanding laboratory and clinical results pertaining to radiopharmaceutical therapy.

Female thyroid cancer : the role of reproductive and hormonal factors in Switzerland

We conducted a study on 91 women with thyroid cancer and 306 controls in hospital for acute nonneoplastic, non-hormone-related disorders in order to investigate the role of reproductive and hormonal factors in the etiology of epithelial thyroid cancer in the Canton of Vaud, Switzerland. Non-significant increases in cancer risk with an increasing number of full-term pregnancies (odds ratio, OR, after allowance for age and previous benign thyroid disease = 1.6, for > or = 3 vs. 0 full-term pregnancies, 95% confidence interval, CI: 0.7-3.6) and spontaneous abortions (OR = 2.0 for > or = 2 vs. 0 spontaneous abortions, 95% CI: 0.7-5.2) were seen. A significantly elevated OR (2.8, 95% CI: 1.1-7.2) was found in those women whose first pregnancy ended with an abortion. Whereas most other reproductive, menstrual and hormonal factors examined did not seem to affect the risk of thyroid cancer significantly, a clue emerged of an association between thyroid cancer and artificial menopause (OR = 6.3, for women who underwent artificial menopause vs. premenopausal women, 95% CI: 1.7-23.2). Although not necessarily causal, the relationship between the risk of epithelial thyroid cancer and the occurrence of spontaneous abortions and artificial menopause deserves attention in future studies, in the light of the high incidence of thyroid cancer in young and middle-aged women.

Secondary Cancer Risk for Stage I Seminoma Patients - a Comparison of Adjuvant Treatment Versus Surveillance

Background: Post-surgical management of stage I seminoma includes: surveillance with repeated CT-scans and treatment reserved for those who relapse, or adjuvant treatment with either immediate radiation therapy (RT) or carboplatin. The cancer specific survival is close to 100%. Cure without long-term sequelae of treatment is the aim. Our goal is to estimate the risk of radiation-induced secondary cancers (SC) death from for patients undergoing S, adjuvant RT or adjuvant carboplatin (AC).Materials and Methods: We measured organ doses from CT scans (3 phases each one) of a seminoma patient who was part of the active surveillance strategy and from a man undergoing adjuvant RT 20-Gy and a 30-Gy salvage RT treatment to the para-aortic area using helical Intensity Modulated RT (Tomotherapy®) with accurate delineation of organs at risk and a CTV to PTV expansion of 1 cm. Effective doses to organs in mSv were estimated according to the tissue-weighting factors recommendations of the International Commission on Radiological Protection 103 (Ann ICRP 2007). We estimated SC incidence and mortality for a 10,000 people population based on the excess absolute risk model from the Biological Effects of Ionizing Radiation (BEIR) VII (Health Risk of Exposure to Low Levels of Ionizing Radiation, NCR, The National Academies Press Washington, DC, 2006) assuming a seminoma diagnosis at age 30, a total life expectancy of 80 years.Results: The nominal risk for a fatal secondary cancers was calculated 1.5% for 15 abdominal CT scans, 14.8% for adjuvant RT (20 Gy paraaortic field) and 22.2% for salvage RT (30 Gy). The calculation assumed that the risk of relapse on surveillance and adjuvant AC was 15% and 4% respectively and that all patients were salvaged at relapse with RT. n CT abdomen/Pelvis = secondary cancer % RT Dose and % receiving treatment = secondary cancer % Total secondary cancer risk in % Active surveillance 15 = 1.5% 30 Gy in 15% of pts = 3.3% 4.8 Adjuvant carboplatin 7 = 0.7% 30 Gy in 4% of pts = 0.88% 1.58 Adjuvant radiotherapy 7 = 0.7% 20 Gy in 100% of pts = 14.8% 15.5Conclusions: These data suggest that: 1) Adjuvant radiotherapy is harmful and should not anymore be regarded as a standard option for seminoma stage I. 2) AC seems to be an option to reduce radiation induced cancers. Limitations: the study does not consider secondary cancers due to chemotherapy with AC (unknown). The use of BEIR VII for risk modeling with higher doses of RT needs to be validated.

Drug targeting strategies for photodynamic therapy.

In human pathologies, therapeutic treatments are often limited by the lack of selectivity of drugs and their elevated effective concentrations. Targeting these agents to a defined tissue could enhance their selectivity and then diminish their side effects when compared to drugs that accumulate in the entire body. Targeting could also improve treatment efficiency by allowing a localized high concentration of the agents. Based on the different behaviors and patterns of expression between diseased and normal cells, strategies for targeting can be explored. For example, receptors, proteases or trans-membrane carriers could be different or differently expressed. Many therapeutic procedures rely on this fact, including photodynamic therapy (PDT). PDT is already used in the treatment of some cancers, of inflammatory diseases and others diseases such as age-related macular degeneration or acne. PDT relies on the activation of a photosensitizer (PS) by visible light which results in the production of cytotoxic reactive oxygen species. In PDT, the general distribution of PS to the whole body leads to generalized photosensitization and poor acceptance of treatments by patients. One way to avoid these effects is to improve the targeting of PSs to diseased tissues using modification of PS with peptides or proteins that will target specific receptors or enzymes. PSs could also be functionalized with non-proteic ligands such as organometalics to achieve targeted and/or combined therapies. Alternatively, PSs could be encapsulated in nanoparticles bearing targeting agents which will decrease concentration of free circulating PS and improve photodynamic efficiency. These different approaches will be discussed in the present review with an emphasis on the use of peptides and proteins.

Edelfosine-induced metabolic changes in cancer cells that precede the overproduction of reactive oxygen species and apoptosis

Background: Metabolic flux profiling based on the analysis of distribution of stable isotope tracer in metabolites is an important method widely used in cancer research to understand the regulation of cell metabolism and elaborate new therapeutic strategies. Recently, we developed software Isodyn, which extends the methodology of kinetic modeling to the analysis of isotopic isomer distribution for the evaluation of cellular metabolic flux profile under relevant conditions. This tool can be applied to reveal the metabolic effect of proapoptotic drug edelfosine in leukemia Jurkat cell line, uncovering the mechanisms of induction of apoptosis in cancer cells. Results: The study of 13C distribution of Jukat cells exposed to low edelfosine concentration, which induces apoptosis in ¿5% of cells, revealed metabolic changes previous to the development of apoptotic program. Specifically, it was found that low dose of edelfosine stimulates the TCA cycle. These metabolic perturbations were coupled with an increase of nucleic acid synthesis de novo, which indicates acceleration of biosynthetic and reparative processes. The further increase of the TCA cycle fluxes, when higher doses of drug applied, eventually enhance reactive oxygen species (ROS) production and trigger apoptotic program. Conclusion: The application of Isodyn to the analysis of mechanism of edelfosine-induced apoptosis revealed primary drug-induced metabolic changes, which are important for the subsequent initiation of apoptotic program. Initiation of such metabolic changes could be exploited in anticancer therapy.

Aetiology and resistance in bacteraemias among adult and paediatric haematology and cancer patients.

OBJECTIVES: A knowledge of current epidemiology and resistance patterns is crucial to the choice of empirical treatment for bacteraemias in haematology and cancer patients. METHODS: A literature review on bacteraemias in cancer patients considered papers published between January 1st 2005 and July 6th 2011. Additionally, in 2011, a questionnaire on the aetiology and resistance in bacteraemias, and empirical treatment, was sent to participants of the European Conference on Infections in Leukemia (ECIL) meetings; recipients were from 80 haematology centres. RESULTS: For the literature review, data from 49 manuscripts were analysed. The questionnaire obtained responses from 39 centres in 18 countries. Compared with the published data, the questionnaire reported more recent data, and showed a reduction of the Gram-positive to Gram-negative ratio (55%:45% vs. 60%:40%), increased rates of enterococci (8% vs. 5%) and Enterobacteriaceae (30% vs. 24%), a decreased rate of Pseudomonas aeruginosa (5% vs. 10%), and lower resistance rates for all bacteria. Nevertheless the median rates of ESBL-producers (15-24%), aminoglycoside-resistant Gram-negatives (5-14%) and carbapenem-resistant P. aeruginosa (5-14%) were substantial, and significantly higher in South-East vs. North-West Europe. CONCLUSIONS: The published epidemiological data on bacteraemias in haematology are scanty and mostly dated. Important differences in aetiology and resistance exist among centres. Updated analyses of the local epidemiology are mandatory to support appropriate empirical therapy.

First explicit criteria to decide on the appropriateness of therapy of ulcerative colitis: the European EPATUC panel

Background: Ulcerative colitis (UC) is a chronic disease with a wide variety of treatment options many of which are not evidence based. Supplementing available guidelines, which are often broadly defined, consensus-based and generally not tailored to specifically reflect the individual patient situation, we developed explicit appropriateness criteria to assist, and improve treatment decisions. Methods: We used the RAND appropriateness method which does not force consensus. An extensive literature review was compiled based on and supplementing, where necessary, the ECCO UC 2011 guidelines. EPATUC (endorsed by ECCO) was formed by 7 gastroenterologists, 2 surgeons and 2 general practitioners from throughout Europe. Clinical scenarios reflecting practice were rated on a 9-point scale from 1 (extremely inappropriate) to 9 (extremely appropriate), based on the expert's experience and the available literature. After extensive discussion, all scenarios were re-rated at a two-day panel meeting. Median and disagreement (D) were used to categorize ratings into 3 categories: appropriate (A), uncertain (U) and inappropriate (I). Results: 718 clinical scenarios were rated, structured in 13 main clinical presentations: not refractory (n = 64) or refractory (n = 33) proctitis, mild to moderate left-sided (n = 72) or extensive (n = 48) colitis, severe colitis (n = 36), steroid- dependant colitis (n = 36), steroid-refractory colitis (n = 55), acute pouchitis (n = 96), maintenance of remission (n = 248), colorectal cancer prevention (n = 9) and fulminant colitis (n = 9). Overall, 100 indications were judged appropriate (14%), 129 uncertain (18%) and 489 inappropriate (68%). Disagreement between experts was very low (6%). Conclusions: For the very first time, explicit appropriateness criteria for therapy of UC were developed that allow both specific and rapid therapeutic decision making and prospective assessment of treatment appropriateness. Comparison of these detailed scenarios with patient profiles encountered in the Swiss IBD cohort study indicates good concordance. EPATUC criteria will be freely accessible on the internet (epatuc.ch)

Combined radioimmunotherapy and radiotherapy of liver metastases from colorectal cancer: a feasibility study.

BACKGROUND: A combination of radioimmunotherapy (RIT) and radiotherapy (RT) should allow one to increase the dose of radiation targeting a particular tumour without the concomitant increase of toxic side effects. This might be obtained if the dose limiting side effect of each individual radiation therapy concerned different organs. METHODS: Six patients with limited liver metastatic disease from colorectal cancer were treated with 6.9 GBq (range 4.7 to 8.4 GBq) 131I-labelled anti-CEA MAb F(ab')2 fragments combined with 20 Gy RT to the liver. Both treatments were given in close association, according to timing schedules evaluated in animals that gave the best results. RESULTS: Reversible bone marrow and liver toxicity was observed in 6 and 5 patients, respectively. Three patients who first received 20 Gy RT to the liver, showed a significant platelet drop upon completion of RT. Repeat computerized tomography (CT) after 2 months showed a minor response in 1 patient and stable disease in 3 patients. CONCLUSION: The study shows potential ways of combining RIT and RT, suggesting that this combination is feasible for the treatment of liver metastases.

Traitements antiangiogéniques des cancers métastatiques du côlon et du rectum, du sein et du poumon: bénéfices et risques [Anti-angiogenic therapies for metastatic colorectal, breast and lung cancer: benefits and risks]

Anti-angiogenic therapies have recently enriched the therapeutic armentarium against the most common cancers. Among these, bevacizumab, a monoclonal antibody against vascular endothelial growth factor, is currently used most frequently. While the addition of bevacizumab to chemotherapy improves overall survival in first and second line treatment of metastatic colorectal cancer, its effect in metastatic breast cancer is limited to improvements in tumor response and progression-free-survival. In non-small-cell lung cancer, the positive results of a first American phase III study have not been confirmed by a second European study and are subject to controversies. A summary of the data concerning anti-angiogenic therapies in these three cancers is presented including safety information.

Optimization and regeneration kinetics of lymphatic-specific photodynamic therapy in the mouse dermis.

Lymphatic vessels transport fluid, antigens, and immune cells to the lymph nodes to orchestrate adaptive immunity and maintain peripheral tolerance. Lymphangiogenesis has been associated with inflammation, cancer metastasis, autoimmunity, tolerance and transplant rejection, and thus, targeted lymphatic ablation is a potential therapeutic strategy for treating or preventing such events. Here we define conditions that lead to specific and local closure of the lymphatic vasculature using photodynamic therapy (PDT). Lymphatic-specific PDT was performed by irradiation of the photosensitizer verteporfin that effectively accumulates within collecting lymphatic vessels after local intradermal injection. We found that anti-lymphatic PDT induced necrosis of endothelial cells and pericytes, which preceded the functional occlusion of lymphatic collectors. This was specific to lymphatic vessels at low verteporfin dose, while higher doses also affected local blood vessels. In contrast, light dose (fluence) did not affect blood vessel perfusion, but did affect regeneration time of occluded lymphatic vessels. Lymphatic vessels eventually regenerated by recanalization of blocked collectors, with a characteristic hyperplasia of peri-lymphatic smooth muscle cells. The restoration of lymphatic function occurred with minimal remodeling of non-lymphatic tissue. Thus, anti-lymphatic PDT allows control of lymphatic ablation and regeneration by alteration of light fluence and photosensitizer dose.

Effect of low-dose chest irradiation before chemotherapy on the rate of local failure in small-cell lung cancer.

PURPOSE: To evaluate the rate of tumor recurrence within the irradiated volume after initial low-dose irradiation of limited-stage small-cell lung cancer (SCLC), to assess the tolerance of a sequential combination of low-dose chest irradiation followed by chemotherapy, and to confirm the responsiveness of limited-stage SCLC to low-dose irradiation. METHODS AND MATERIALS: In this pilot study, 26 patients with limited-stage SCLC were treated by first-line 20-Gy thoracic irradiation followed 3 weeks later by chemotherapy (cisplatin, doxorubicin, and etoposide for six cycles). RESULTS: We present our final results with a median follow-up of surviving patients of 7 years. The response rate to this low-dose irradiation was 83%, with an overall response rate to radiochemotherapy of 96% and a median survival of 21 months. No unexpected early or late toxicity was observed. The rate of initial isolated local failure was 8%, which compares favorably with other published series using higher doses of radiochemotherapy. CONCLUSION: An initial chest irradiation of 20 Gy before chemotherapy could be sufficient to reduce the risk of local failure during the time of survival of patients with limited-stage SCLC. Potential advantages of this treatment may be the prevention of resistance mechanisms to radiotherapy induced by preliminary chemotherapy and a reduced radiation-induced toxicity.

Busulphan-melphalan is the superior myeloablative therapy (mat) for high risk neuroblastoma: results from the hr-nbl1/siopen trial

Purpose: The HR-NBL1 trial of the European SIOP Neuroblastoma Group randomised 2 MAT regimens to demonstrate superiority based on event free survival (EFS).Method: Response eligibility criteria prior to randomisation after Rapid COJEC Induction (J Clin Oncol, 2010) 3 4 2 courses of TVD (Cancer, 2003) included complete bone marrow remission andA ^ 3, but improved, mIBG positive spots. The MAT regimens were BuMel (oral busulfan till 2006, 4_150 mg/m2 in 4 equal doses, or after 2006 intravenous use according to body weight and melphalan 140 mg/m__/day) and CEM (carboplatin ctn. infusion (4xAUC 4.1 mg/ml.min/day), etoposide ctn. infusion (4_338 mg/m__day or 4_200 mg/m__/ day*), melphalan (3_70 mg/m__/day or 3_60 mg/m__/day*. *reduced if GFR<100 ml/ min/1.73m__)). A minimum of 3_10E6 CD34/kgBW PBSC were requested. VOD prophylaxis included ursadiol, but not prophylactic defibrotide. Local control included surgery and radiotherapy of 21 Gy. A total of 598 high risk neuroblastoma patients were randomised (296 BuMel, 302 CEM). The median age at randomisation was 3 years (1-17.2).Results: A significant difference in EFS in favour of BuMel (3-years EFS 49% vs. 33%) was observed as well as for overall survival (3-years OS 60% vs. 48%, p¼0.004) with a median follow up of 3 years. This difference was mainly related to the relapse and progression incidence, which was significantly (p<0.001) lower with BuMel (48% vs. 60%). The severe toxicity rate up to day 100 (ICU and toxic deaths) was below 10%, but was significantly higher for CEM (p¼0.014). The acute toxic death rate was 3% for BuMel and 5% for CEM (NS). The acute MAT toxicity profile favours the BuMel regimen in spite of a total VOD incidence of 18% (grade 3:5%). Based on these results and following advice from the DMC, the randomisation was closed early.

A phase I pharmacokinetic study of hypoxic abdominal stop-flow perfusion with gemcitabine in patients with advanced pancreatic cancer and refractory malignant ascites

PURPOSE: As no curative treatment for advanced pancreatic and biliary cancer with malignant ascites exists, new modalities possibly improving the response to available chemotherapies must be explored. This phase I study assesses the feasibility, tolerability and pharmacokinetics of a regional treatment of gemcitabine administered in escalating doses by the stop-flow approach to patients with advanced abdominal malignancies (adenocarcinoma of the pancreas, n = 8, and cholangiocarcinoma of the liver, n = 1). EXPERIMENTAL DESIGN: Gemcitabine at 500, 750 and 1,125 mg/m(2) was administered to three patients at each dose level by loco-regional chemotherapy, using hypoxic abdominal stop-flow perfusion. This was achieved by an aorto-caval occlusion by balloon catheters connected to an extracorporeal circuit. Gemcitabine and its main metabolite 2',2'-difluorodeoxyuridine (dFdU) concentrations were measured by high performance liquid chromatography with UV detection in the extracorporeal circuit during the 20 min of stop-flow perfusion, and in peripheral plasma for 420 min. Blood gases were monitored during the stop-flow perfusion and hypoxia was considered stringent if two of the following endpoints were met: pH </= 7.2, pO(2) nadir ratio </=0.70 or pCO(2) peak ratio >/=1.35. The tolerability of this procedure was also assessed. RESULTS: Stringent hypoxia was achieved in four patients. Very high levels of gemcitabine were rapidly reached in the extracorporeal circuit during the 20 min of stop-flow perfusion, with C (max) levels in the abdominal circuit of 246 (+/-37%), 2,039 (+/-77%) and 4,780 (+/-7.3%) mug/ml for the three dose levels 500, 750 and 1,125 mg/m(2), respectively. These C (max) were between 13 (+/-51%) and 290 (+/-12%) times higher than those measured in the peripheral plasma. Similarly, the abdominal exposure to gemcitabine, calculated as AUC(t0-20), was between 5.5 (+/-43%) and 200 (+/-66%)-fold higher than the systemic exposure. Loco-regional exposure to gemcitabine was statistically higher in presence of stringent hypoxia (P < 0.01 for C (max) and AUC(t0-20), both normalised to the gemcitabine dose). Toxicities were acceptable considering the complexity of the procedure and were mostly hepatic; it was not possible to differentiate the respective contributions of systemic and regional exposures. A significant correlation (P < 0.05) was found between systemic C (max) of gemcitabine and the nadir of both leucocytes and neutrophils. CONCLUSIONS: Regional exposure to gemcitabine-the current standard drug for advanced adenocarcinoma of the pancreas-can be markedly enhanced using an optimised hypoxic stop-flow perfusion technique, with acceptable toxicities up to a dose of 1,125 mg/m(2). However, the activity of gemcitabine under hypoxic conditions is not as firmly established as that of other drugs such as mitomycin C, melphalan or tirapazamine. Further studies of this investigational modality, but with bioreductive drugs, are therefore warranted first to evaluate the tolerance in a phase I study and later on to assess whether it does improve the response to chemotherapy.