Active specific immunotherapy for stage II and stage III human colon cancer: a randomised trial

Background Colon cancer is curable by surgery, but cure rate depends on the extent of disease. We investigated whether adjuvant active specific immuno therapy (ASI) with an autologous tumour cell-BCG Vaccine with surgical rese ction was more beneficial than resection alone in stage II and III colon ca ncer. Methods In a prospective randomised trial, 254 patients with colon cancer w ere randomly assigned postoperative ASI or no adjuvant treatment. ASI was t hree weekly vaccinations starting 4 weeks after surgery, with a booster Vac cination at 6 months with 10(7) irradiated autologous tumour cells. The fir st Vaccinations contained 107 BCG organisms. We followed up patients for ti me to recurrence, and recurrence-free and overall survival. Analysis was by intention to treat. Findings The 5.3 year median follow-up (range 8 months to 8 years 11 months ) showed 44% (95% CI 7-66) risk reduction for recurrence in the recurrence- free period in all patients receiving ASI (p = 0.023). Overall, there were 40 recurrences in the control group and 25 in the ASI group. Analysis by st age showed no significant benefit of ASI in stage III disease. The major im pact of ASI was seen in patients with stage II disease, with a significantl y longer recurrence-free period (p = 0.011) and 61% (18-81) risk reduction for recurrences. Recurrence-free survival was significantly longer with ASI (42% risk reduction for recurrence or death [0-68], p = 0.032) and there w as a trend towards improved overall survival. Interpretation ASI gave significant clinical benefit in surgically resected patients with stage II colon cancer. ASI has minimal adverse reactions and should be considered in the management of stage II colon cancer.