Objective: The main goal of the current study was to compare survival differences among subgroups of primary ovarian cancer patients in International Federation of Gynecology and Obstetrics (FIGO) stages IIIC and IIIA1 after complete tumor debulking surgery.
Methods: A total of 218 patients with primary ovarian cancer who received complete cytoreductive surgery were included in the current retrospective analysis of the validated Tumor Bank Ovarian Cancer Network Database, which covers the periods January 2002 until December 2012. According to their tumor spread pattern, patients were divided into three groups: Group A (peritoneum only), Group B (peritoneum and lymph nodes), and Group C (lymph nodes only). Associations between groups and clinicopathological factors were analyzed using standard statistical procedures.
Results: The vast majority of patients were classified into Group B. Lymph node involvement was detected in 70.5 % of the cases where peritoneal implants presented ≥2 cm beyond the pelvis (Group A + B). The estimated 5-year overall survival (OS) rates were 47.4 % in Group A, 45.1 % in Group B, and 91.7 % in Group C (p < 0.01). In the subgroup analysis of Group B, both pelvic and para-aortic lymph node involvement was found in 57 % of patients. Patients in Group B who had para-aortic lymph node involvement only had better median progression-free survival (PFS) compared with patients with pelvic lymph node involvement only and pelvic and para-aortic lymph node involvement (28, 16, and 18 months, respectively; p = 0.02). The median OS differed significantly between patients with para-aortic lymph node involvement only versus patients with both pelvic and para-aortic involvement (68.5 vs. 46.7 months; p = 0.02). Three-year PFS was 90.0 % in FIGO IIIA1(i) and 62.6 % in FIGO IIIA1(ii) (hazard ratio 2.30, 95 % confidence interval 0.45-11.58).
Conclusions: Patients with FIGO stage IIIC with lymph node involvement only had the best clinical outcome compared with patients in the same stage with peritoneal involvement only. Furthermore, involvement of both pelvic and para-aortic lymph nodes were of the same infrequency, and involvement of only para-aortic lymph nodes in this stage resulted in a better chance of survival than involvement of pelvic lymph nodes only or both pelvic and para-aortic lymph nodes simultaneously. In accordance with the revised FIGO classification of 2013, our study revealed that FIGO IIIA1(i) is prognostically better compared with FIGO IIIA1(ii).