The prognostic value of pretreatment CA 125 in patients with advanced ovarian carcinoma: a Gynecologic Oncology Group study

Abstract

Background: The objective of the current study was to determine the prognostic significance of a pretreatment serum CA 125 level in patients with advanced epithelial ovarian carcinoma (EOC) who received treatment with a standard chemotherapy regimen.

Methods: Patients with International Federation of Gynecology and Obstetrics stage III/IV ovarian carcinoma who were on 1 of 7 Gynecologic Oncology Group (GOG) phase 3 trials and received treatment with a standard regimen of intravenous cisplatin and paclitaxel were included. A Cox regression model was used to assess the impact of CA 125 levels drawn before the initiation of chemotherapy on progression-free survival (PFS) both overall and by subgroup, including surgical debulking status, disease stage, and histologic subtype.

Results: In total, 1,299 patients who were on the cisplatin/paclitaxel arms of the GOG trials were eligible. The median CA 125 level was 246 U/mL. Only 7.6% of patients had a normal CA 125 level (<or=35 U/mL). The lowest median CA 125 level was observed in the group with mucinous tumors; however, 69% of women who had mucinous tumors had abnormal CA 125 levels. Shorter PFS was observed with increasing CA 125 and persisted in multivariate analysis. Overall and in the serous subgroup, a 1-fold increase in CA 125 level was associated with a 7% increase in the hazard of disease progression (P < .001). This association was even more pronounced in patients who had stage III disease that was debulked to microscopic disease (15%; P = .003) and in patients who had endometrioid tumors (17%; P = .001).

Conclusions: A normal CA 125 level in the setting of advanced EOC was rare even after surgical debulking. The pretreatment CA 125 level was an independent predictor of PFS in patients with advanced EOC who received a standard chemotherapy regimen, particularly in the setting of disease that was debulked to a microscopic residual and in the serous or endometrioid subtypes.

FIGURE 1

Estimate for Progression-free Survival by CA-125 Level

FIGURE 2

ASSOCIATION OF PRETREATMENT CA-125 LEVEL WITH DISEASE PROGRESSION

FIGURE 3

FIGURE 3A. ASSOCIATION OF PRETREATMENT CA-125 WITH DISEASE PROGRESSION BY STAGE/SURGICAL DEBULKING STATUS Adjusted hazard ratio reported as one-fold increase in pretreatment CA-125 level. Stage/debulking status reported for Stage III disease optimally debulked to a microscopic residual, Stage III disease optimally debulked to ≤1 cm residual, Stage III disease suboptimally debulked, and Stage IV disease. FIGURE 3B. ASSOCIATION OF PRETREATMENT CA-125 WITH DISEASE PROGRESSION BY HISTOLOGIC SUBTYPE Adjusted hazard ratio reported as one-fold increase in pretreatment CA-125 level.

FIGURE 3

FIGURE 3A. ASSOCIATION OF PRETREATMENT CA-125 WITH DISEASE PROGRESSION BY STAGE/SURGICAL DEBULKING STATUS Adjusted hazard ratio reported as one-fold increase in pretreatment CA-125 level. Stage/debulking status reported for Stage III disease optimally debulked to a microscopic residual, Stage III disease optimally debulked to ≤1 cm residual, Stage III disease suboptimally debulked, and Stage IV disease. FIGURE 3B. ASSOCIATION OF PRETREATMENT CA-125 WITH DISEASE PROGRESSION BY HISTOLOGIC SUBTYPE Adjusted hazard ratio reported as one-fold increase in pretreatment CA-125 level.