CA-125 change after chemotherapy in prediction of treatment outcome among advanced mucinous and clear cell epithelial ovarian cancers: a Gynecologic Oncology Group study.

Background: There are limited data regarding unique clinical or laboratory features associated with advanced clear cell (CC) and mucinous (MU) epithelial ovarian cancers (EOC), particularly the relationship between CA-125 antigen levels and prognosis.

Methods: A retrospective review of 7 previously reported Gynecologic Oncology Group phase 3 trials in patients with stage III/IV EOC was conducted. A variety of clinical parameters were examined, including the impact of baseline and changes in the CA-125 level after treatment of CC and MU EOC on progression-free (PFS) and overall survival (OS).

Results: Clinical outcomes among patients with advanced CC and MU EOC were significantly worse when compared with other cell types (median PFS, 9.7 vs 7.0 vs 16.7 months, respectively, P < .001; median OS, 19.4 vs 11.3 vs 40.5 months, respectively, P < .001). Suboptimal debulking was associated with significantly decreased PFS and OS among both. Although baseline CA-125 values were lower in CC (median, 154 micron/mL) and MU (100 micron/mL), compared with other cell types (275 micron/mL), this level did not appear to influence outcome among these 2 specific subtypes of EOC. However, an elevated level of CA-125 at the end of chemotherapy was significantly associated with decreased PFS and OS (P < .01 for all).

Conclusions: Surgical debulking status is the most important variable at prechemotherapy predictive of prognosis among advanced CC and MU EOC patients. Changes in the CA-125 levels at the end treatment as compared with baseline can serve as valid indicators of PFS and OS, and likely the degree of inherent chemosensitivity.