Pretreatment CA-125 and risk of relapse in advanced ovarian cancer

Abstract

Purpose: A previous report suggested the nadir serum CA-125 level within the group of patients with ovarian cancer who achieved normalization of CA-125 accurately defined the risk of relapse. Using similar CA-125 subgroups, we sought to determine if the baseline CA-125 level before initiation of maintenance chemotherapy in women achieving a clinically-defined complete response to primary chemotherapy would be of prognostic value.

Patients and methods: Patients included in this retrospective analysis had been treated on one of two previously reported trials of maintenance chemotherapy (three v 12-monthly cycles of paclitaxel; oral altretamine), with a baseline CA-125 level of < or = 35 u/mL. Progression-free survival (PFS) from study entry was analyzed by the Cox regression model.

Results: The distribution of premaintenance baseline CA-125 levels for the 384 patients was 58%, 34%, and 8% for values of (A) < or = 10 u/mL, (B) 11 to 20 u/mL, and (C) 21 to 35 u/mL, respectively. The baseline CA-125 was highly statistically significant, either as a categoric variable (P < .001) or as a continuous variable (P < .0001). Median PFS was 24 months, 17 months, and 7 months for groups (A), (B), and (C), respectively. There was no evidence the CA-125 effect differed by trial or treatment in an interaction analysis (P = .70).

Conclusion: The baseline CA-125 level before initiation of maintenance chemotherapy strongly predicts the risk of subsequent relapse. Patients with premaintenance baseline CA-125 values < or = 10 u/mL have a superior PFS compared with higher levels in the normal CA-125 range.