Prognostic value of elevated preoperative serum CA125 in ovarian tumors of low malignant potential: a multinational collaborative study (ANZGOG0801)

Objective: Previous studies on prognostic factors in ovarian tumors of low malignant potential (LMP) were too small for robust conclusions. We examined the prognostic impact of preoperative serum CA125 ≥ 50 U/ml levels in patients diagnosed with ovarian LMP tumors in a large multinational cohort.

Methods: This retrospective study included 940 patients with ovarian LMP tumors diagnosed between 1985 and 2008 at six gynecologic cancer centers. Patients either had radical treatment (bilateral salpingo-oophorectomy with or without hysterectomy) or conservative, fertility-sparing treatment. Multivariate Cox proportional hazard models were used to determine independent prognostic factors for disease-free (DFS) and overall survival (OS). Based on receiver operating characteristic curve (ROC), a preoperative serum CA125 level ≥ 50 U/ml was considered "elevated".

Results: CA125 was more often elevated in serous than in mucinous tumors and in advanced FIGO stages (2 to 4) compared to stage 1. DFS at 5 years was 89% and 95% in patients with elevated and normal CA125 levels (p<0.05). Similarly, the 5-year OS was 90% among patients with elevated CA125 compared to 95% among patients with normal levels (p<0.05). For both DFS and OS elevated CA125 levels and advanced stages of the disease were independent prognostic factors. Analysis of subgroups revealed that CA125 was only prognostic in serous LMP tumors.

Conclusions: In the context of serous ovarian LMP tumors, elevated preoperative serum CA125 represents a biomarker independently associated with impaired disease-free and overall survival. CA125 is available in most centers and could inform surgeons about the risk of treatment failure.