International Collaborative Ovarian Neoplasm trial 1: a randomized trial of adjuvant chemotherapy in women with early-stage ovarian cancer

BACKGROUND: The question of whether platinum-based adjuvant chemotherapy can improve outcomes in patients with early-stage epithelial ovarian cancer is an important one. We carried out a multicenter, open randomized trial to determine whether adjuvant chemotherapy would improve overall survival and prolong recurrence-free survival in women with early-stage epithelial ovarian cancer. METHODS: Between August 1991 and January 2000, 477 patients in 84 centers in five countries were randomly assigned to receive either adjuvant chemotherapy immediately following surgery (n = 241) or no adjuvant chemotherapy until clinically indicated (n = 236). Kaplan-Meier curves of overall survival and recurrence-free survival were compared using the Mantel-Cox version of the log-rank test. All statistical tests were two-sided. RESULTS: Women who received adjuvant chemotherapy had better overall survival than women who did not (hazard ratio HR] of 0.66, 95% confidence interval CI] = 0.45 to 0.97; P =.03). These results translate into 5-year survival figures of 70% for women who did not receive adjuvant chemotherapy and 79% for women who did receive adjuvant chemotherapy, a difference of 9% (95% CI = 1% to 15%). Adjuvant chemotherapy also improved recurrence-free survival (HR = 0.65; 95% CI = 0.46 to 0.91; P =.01). These results translate into 5-year recurrence-free survival figures of 62% for women who did not receive adjuvant chemotherapy and 73% for women who did receive adjuvant chemotherapy, a difference of 11% (95% CI = 3% to 18%). CONCLUSION: These results suggest that platinum-based adjuvant chemotherapy improves survival and delays recurrence in patients with early-stage ovarian cancer.