Aims and background: Trials of adjuvant systemic therapy in high risk patients with Dukes' B2 and C colon cancer utilizing 5-fluorouracil-based regimens have been ongoing since the 1960s. The aim of this study was to compare the combination of 5-FU and leucovorin with the combination of 5-FU and alfa-2b interferon (IFN) in patients who had undergone "curative" resection foronocarcinoma.
Study design: A total of 322 patients with histologically proven adenocarcinoma of the colon, Dukes' stage B2 and C, were entered in the study. They were randomized to A) leucovorin 20 mg/m2 rapid intravenous injection and 5-FU 425 mg/m2 IV days 1-5 every 28 days for six cycles or B) 5-FU 600 mg/m2 24-hour infusion for five days, then 600 mg/m2 IV once a week and IFN 5 MU subcutaneously three times a week for six months.
Results: There was no statistically significant difference in either disease-free survival or overall survival. Toxicity was the same in the two groups with the exception of flu-like syndrome, which was universal in IFN-treated patients.
Conclusions: There was no difference in disease-free survival or overall survival between the two combinations in any patient subset. Toxicity was greater with the 5-FU+IFN combination because of the flu-like syndrome. These data do not support the use of IFN in combination with 5-FU as systemic adjuvant therapy for patients with locally advanced colon carcinoma.