Significance of postoperative CA-125 decline after cytoreductive surgery in stage IIIC/IV ovarian cancer.

OBJECTIVE The purpose of this study was to evaluate whether the decline in serum CA-125 levels following primary cytoreductive surgery prior to starting adjuvant chemotherapy has a prognostic value in patients with stage IIIC/IV ovarian carcinoma. METHODS A retrospective review was conducted of all patients with stage IIIC/IV ovarian carcinoma who underwent primary cytoreductive surgery followed by platinum-based chemotherapy from 1994 to 2007. Demographic, pathologic, treatment, and survival data were collected. Patients were included if serum CA-125 levels were drawn preoperatively and within one week prior to their first chemotherapy cycle, and whose postoperative CA-125 level declined. Percentage decline was calculated, and was compared with standard statistical tests in groups by 25% declination intervals. RESULTS Of the 112 stage IIIC/IV patients, 81 (72.3%) met the above inclusion criteria. The median time from surgery to postoperative CA-125 sampling was 16 days (range: 7-42). A >/=75% decline was associated with a median progression-free survival (PFS) of 25 months (95% CI=0-63). This was significantly longer when compared with each of the other 25% interval groups. After multivariate analysis, independent prognostic factors included a >/=75% decline in CA-125 levels after surgery and the presence of residual tumor. Age, grade, histology, and preoperative CA-125 levels were not statistically significant factors. CONCLUSION A >/=75% decline in serum CA-125 serum levels from primary cytoreductive surgery to the start of adjuvant chemotherapy has independent prognostic value for PFS in patients with stage IIIC/IV ovarian carcinoma.