Nadir CA-125 concentration in the normal range as an independent prognostic factor for optimally treated advanced epithelial ovarian cancer

Background: The amount of residual disease after surgery is considered the most important factor influencing the survival of patients with advanced epithelial ovarian cancer (adEOC). In optimally treated patients with adEOC, there are no well-established prognostic factors [excluding International Federation of Gynecology and Obstetrics (FIGO) stage]. The aim of this retrospective study is to analyze the prognostic value of the CA-125 nadir after the completion of an optimal primary treatment. Patients and methods: Patients treated for adEOC were identified from January 1998 to December 2006. Inclusion criteria: elevated CA-125 at time of diagnosis (>35 kU/l); FIGO stage III-IV treated with optimal primary treatment (residual tumor <1 cm and carboplatin/taxane- based combination chemotherapy); and complete response to optimal primary treatment with normalization of CA-125. Results: Patients, n = 96: 44 group A (<= 10 kU/l); 52 group B (11-35 kU/l). Median progression-free survival (PFS) was 42 and 20 months for groups A and B, respectively (P = 0.0087). Median overall survival (OS) was 84 and 43 months for groups A and B, respectively (P < 0.0001). The Cox model showed a highly significant impact on PFS and OS in relation to CA-125 nadir levels. Conclusions: The CA-125 nadir value is a strong independent prognostic factor for optimally treated adEOC after achieving a complete response.