Findings at reassessment laparotomy and disease-free survival are reported for a group of patients with advanced-stage epithelial ovarian cancer who have had a complete clinical response to cytoreductive surgery and multiagent platinum-based chemotherapy. The predictive value of the number of chemotherapy cycles to achieve a serum CA125 of < 35 U/ml is compared to the predictive value of s, the rate of achieving a normal serum CA125. s is generated from an exponential regression model. This study suggests that s accurately predicts which patients have residual disease at reassessment laparotomy, who will be free of disease, and, of those in the latter group, who are at greatest risk to recur, as well as overall survival. If these observations are confirmed, physicians may base further therapeutic intervention on the basis of a calculated parameter following complete clinical response to first-line treatment rather than relying on findings at reassessment laparotomy.