QUASAR: A randomized study of adjuvant chemotherapy (CT) vs observation including 3238 colorectal cancer patients

3501 Background: The size of survival benefit from adjuvant fluorouracil/folinic acid (FUFA) CT for colorectal cancer is unclear. Methods: Patients with apparently curative resections of colon or rectal cancer were randomized following surgery between FUFA and observation (with CT considered on recurrence). CT consisted of either six 5-day, four-weekly or 30 once-weekly courses of intravenous fluorouracil (370mg/m2) with either high-dose (175mg) or low-dose (25mg) L-folinic acid, and with either levamisole or placebo. Primary outcome was all cause mortality. Results: Between June 1994 and December 2003, 3238 patients (91% Dukes B, 71% colon cancer, median age 63) from 150 centres in 17 countries were randomised. Direct randomised comparisons found no benefit for high-dose FA or levamisole (Lancet 2000;355:1588–1596). A non-randomised comparison suggested equal efficacy but less toxicity with the once-weekly schedule (Annals of Oncology 2000;11:947–955). With a median follow-up of 4.2 years, risk of death ...