EARLY EVALUATION OF COMBINED FLUOROURACIL AND LEUCOVORIN AS A RADIATION ENHANCER FOR LOCALLY UNRESECTABLE, RESIDUAL, OR RECURRENT GASTROINTESTINAL CARCINOMA

Purpose: To develop a tolerable regimen of fluorouracil (5-FU), low-dose leucovorin, and radiation, and to obtain an early estimate of therapeutic effectiveness. Patients and Methods: Forty patients with locally unresectable or recurrent gastrointestinal carcinoma were studied (pancreas, n = 22; rectum and sigmoid, n = 10; gastric, n = 6; other, n = 2). Irradiation therapy was administered in 1.8-Gy fractions 5 days per week, with total doses ranging from 45 to 54 Gy. 5-FU 400 mg/m2/d plus leucovorin 20 mg/m2/d, both by rapid intravenous injection, were administered for 3 or 4 days during the first and fifth weeks of radiation. 5-FU 425 mg/m2/d plus leucovorin 20 mg/m2/d were administered for 4 days at 4 weeks following radiation and for 5 days at 9 weeks. Results: Major toxicities with upper abdominal treatment were nausea, vomiting, weight loss, and leukopenia. A tolerable dosage regimen was radiation at 45 Gy with 4 days of 5-FU plus leucovorin during the first week and 3 days during the last week with postradiation chemotherapy. Major toxicities with pelvic radiation were diarrhea and leukopenia. A tolerable regimen was 54 Gy with 4 days of 5-FU plus leucovorin during the first and fifth week followed by the postradiation chemotherapy. Median survival durations for pancreatic and rectal/sigmoid carcinomas are 13 months and 31 months, respectively. Five patients have no evidence of disease from 38 to 50 months after the onset of therapy (rectal, n = 2; stomach, n = 2; pancreas, n = 1). Conclusion: We have developed patient-tolerable regimens for combined 5-FU plus leucovorin followed by radiation to the abdomen and to the pelvis. The favorable results observed in locally unresectable disease allow cautious optimism for possible effectiveness in the surgical adjuvant setting, a possibility currently being tested in national trials of rectal and gastric carcinoma.