ADJUVANT LEVAMISOLE AND FLUOROURACIL IN HIGH-RISK COLORECTAL-CANCER PATIENTS - A PHASE-II STUDY USING LEVAMISOLE IN A LOWER DOSE

Adjuvant chemotherapy in colorectal cancer patients is aimed at decrea sing the relapse rate of the disease and increasing the disease-free a nd the overall survival of the patients. In a prospective study we eva luated the efficacy of 5-FU plus levamisole as an aduvant therapy for 153 patients with Dukes' B-2 or C colon or rectal cancer following a c urative-intended surgery. Adjuvant chemotherapy was started within 4 t o 6 weeks following the operation. Combination of 5-FU 375 mg/m(2)/day was given intravenously over 15-20 min for 5 consecutive days, every month for 1 year. Levamisole 50 mg t.i.d. was administered orally duri ng the first 3 days of each course of chemotherapy. Rectal cancer pati ents were also irradiated to the tumor bed and pelvic lymphatics. The dose intensities (DI) of 5-FU and levamisole in our study were 432.6 m g/m(2)/w and 103.8 mg/m(2)/w, respectively. Failure analysis in Dukes' B and C patients showed that the rectum accounted for 47.5% of the re lapses, of which only 3 cases were in the vicinity of the resected are a. Almost half of the failures were observed within the year of adjuva nt treatment. The liver was the most common site for first relapse (50 %). The 3-year disease-free survival of Dukes' B-2 patients group was 84%, compared with 64% in Dukes' C. The main toxic manifestations were diarrhea, nausea and vomiting, weakness and mucositis. No dose reduct ion was needed. Our protocol, using lower DI of levamisole yielded sim ilar results with a lower rate of toxicity than other common protocols .