ABSTRACT
For the systemic treatment of colorectal cancer, 5-fluorouracil (FU)-based chemotherapy is the standard. However, only a subset of patients responds to chemotherapy. Breathing of carbogen (95% O2 and 5% CO2) may increase the uptake of FU through changes in tumor physiology. This study aims to monitor in animal models in vivo the effects of carbogen breathing on tumor blood plasma volume, pH, and energy status, and on FU uptake and metabolism in two colon tumor models C38 and C26a, which differ in their vascular structure and hypoxic status. Phosphorus-31 magnetic resonance spectroscopy (MRS) was used to assess tumor pH and energy status, and fluorine-19 MRS was used to follow FU uptake and metabolism. Advanced magnetic resonance imaging methods using ultrasmall particles of iron oxide were performed to assess blood plasma volume. The results showed that carbogen breathing significantly decreased extracellular pH and increased tumor blood plasma volume and FU uptake in tumors. These effects were most significant in the C38 tumor line, which has the largest relative vascular area. In the C26a tumor line, carbogen breathing increased tumor growth delay by FU. In this study, carbogen breathing also enhanced systemic toxicity by FU.
Subject(s)
Antimetabolites, Antineoplastic/pharmacology , Carbon Dioxide/chemistry , Colonic Neoplasms/drug therapy , Fluorouracil/pharmacology , Neovascularization, Pathologic , Oxygen/chemistry , Radiation-Sensitizing Agents/pharmacology , Animals , Cell Line, Tumor , Colonic Neoplasms/blood , Disease Models, Animal , Fluorine Radioisotopes/therapeutic use , Hydrogen-Ion Concentration , Magnetic Resonance Spectroscopy/methods , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Phosphorus Radioisotopes , Plasma/metabolism , RespirationABSTRACT
PURPOSE: To define the efficacy and toxicity of docetaxel plus gemcitabine or docetaxel plus cisplatin for advanced pancreatic carcinoma. PATIENTS AND METHODS: Chemotherapy-naive patients with measurable disease and WHO performance status less than 2 were randomly assigned to receive 21-day cycles of gemcitabine 800 mg/m2 on days 1 and 8 plus docetaxel 85 mg/m2 on day 8 (arm A) or docetaxel 75 mg/m2 on day 1 plus cisplatin 75 mg/m2 on day 1 (arm B). Primary end points were tumor response and rate of febrile neutropenia grade. RESULTS: Of 96 randomly assigned patients (49 patients in arm A and 47 patients in arm B), 70 patients were analyzed for response (36 in arm A and 34 in arm B) and 89 patients were analyzed for safety (45 in arm A and 44 in arm B). Confirmed responses were observed in 19.4% (95% CI, 8.2% to 36.0%) of patients in arm A and 23.5% (95% CI, 10.7% to 41.2%) in arm B. In arm A, the median progression-free survival (PFS) was 3.9 months (95% CI, 3.0 to 4.7 months), median survival was 7.4 months (95% CI, 5.6 to 11.0 months), and 1-year survival was 30%. In arm B, the median PFS was 2.8 months (95% CI, 2.6 to 4.6 months), median survival was 7.1 months (95% CI, 4.8 to 8.7 months), and 1-year survival was 16%. Febrile neutropenia occurred in 9% and 16% of patients in arms A and B, respectively. CONCLUSION: Both regimens are well tolerated and show activity in advanced pancreatic carcinoma. The safety profile and survival analyses favor docetaxel plus gemcitabine for further evaluation.
