T Buroker

PURPOSE: To compare two commonly used schedules of fluorouracil (5FU) and leucovorin in the treatment of patients with advanced metastatic colorectal cancer. Each of these dosage administration schedules has been demonstrated to be superior to single-agent bolus 5FU in previous controlled trials. PATIENTS AND METHODS: Three hundred seventy-two ambulatory patients with metastatic colorectal cancer were stratified according to performance status, and presence and location of any measurable indicator lesion(s). They were then randomized to receive chemotherapy with one of the following regimens: (1) intensive-course 5FU plus low-dose leucovorin (5FU 425 mg/m2 plus leucovorin 20 mg/m2 intravenous [IV] push daily for 5 days with courses repeated at 4- to 5-week intervals); (2) weekly 5FU plus high-dose leucovorin (5FU 600 mg/m2 IV push plus leucovorin 500 mg/m2 as a 2-hour infusion weekly for 6 weeks with courses repeated every 8 weeks). RESULTS: Three hundred sixty-two of 372 patients randomized (97.3%) were eligible and included in the analysis. Three hundred forty-six patients (95.6%) have died. There were no significant differences in therapeutic efficacy between the two 5FU/leucovorin regimens tested with respect to the following parameters: objective tumor response (35% v 31%), survival (median, 9.3 v 10.7 months), and palliative effects (as assessed by relief of symptoms, improved performance status, and weight gain). There were significant (P < .05) differences in toxicity, with more leukopenia and stomatitis seen with the intensive-course regimen, and more diarrhea and requirement for hospitalization to manage toxicity with the weekly regimen. Financial cost was also higher with the weekly regimen. CONCLUSION: Intensive-course 5FU plus low-dose leucovorin appears to have a superior therapeutic index compared with weekly 5FU plus high-dose leucovorin using the dosage administration schedules applied in this study based on similar therapeutic effectiveness, but lower financial cost, and less need for hospitalization to manage chemotherapy toxicity.

Pharmacokinetic studies of 5-fluorouracil (5-FUra) were performed on 18 patients divided into three groups: seven patients were given 5-FUra i.v. by rapid injection; five patients received the drug p.o.; and six patients were treated by continuous i.v. infusion for 96 hr. The results showed rapid i.v. injection to be manifested by high early levels of drug achieved both in plasma and bone marrow with a rapid fall afterwards. Administration of 5-FUra p.o. gave rise to erratic plasma values due to greater variability in absorption, whereas 96-hr i.v. infusions showed constant levels of the drug in plasma and significantly (50- to 1000-fold) less 5-FUra in bone marrow. The main difference observed between rapid injection and slow infusion in the kinetics of the drug was the very high level of 5-FUra reached by rapid injection in plasma and bone marrow, which was of short duration (min) when compared to the low sustained levels observed during infusion. This route-dependent pharmacokinetic profile is consistent with the reported absence of myelosuppression in prolonged infusion and may be related to the resultant lower levels of 5-FUra achieved in bone marrow.

Nineteen patients with squamous-cell cancer of the anal canal have been treated with combined chemotherapy and radiation therapy, followed by appropriate surgery. The authors are convinced that the combined therapy is effective enough to avoid abdominoperineal resection if disappearance of the lesion is proven by adequate examination and biopsy. Although they believe cancers 5 cm or less in maximum diameter are generally adequately managed in this manner, experience is still too limited to justify a recommendation to change currently accepted management.