Adjuvant sequential methotrexate → 5-fluorouracil vs 5-fluorouracil plus leucovorin in radically resected stage III and high-risk stage II colon cancer

The aim of the study was to determine whether modulation of 5-fluorouracil (FU) by methotrexate (MTX) improves survival compared to FU + 6-s-leucovorin (LV) following potentially curative resection of stage II and III colon cancer. Within 8 weeks from surgery, 1945 patients with stage III (44%) or high-risk stage II (55%) colon cancer were randomly assigned to receive either 6 monthly cycles of FU 370 mg m^-2 i.v. bolus preceded by LV 100 mg m ^-2 i.v. bolus on days 1-5, or 6 monthly cycles of sequential MTX 200 mg m^-2 i.v. days 1 and 15 and FU 600 mg m^-2 i.v. on days 2 and 16 followed by LV rescue (15 mg given p.o. q 6h × 6 doses). Levamisole 50 mg p.o. t.i.d. on days 1-3, every 14 days for 6 months, was planned to be given in both arms. After a median follow-up of 4.2 years, 568 patients have relapsed and 403 have died. Survival was similar with MTX → FU and FU + LV (77 vs 77% at 5 years; P = 0.90), as were 5-year disease-free survivals (67 vs 63%; P = 0.44). Efficacy results were similar for both stage III and II patients. There were two toxic deaths, two in the MTX → FU arm (0.2%) and zero in the control arm. We conclude that biochemical modulation of FU with LV or with MTX produces similar results in the adjuvant setting of colon cancer.