Validity of the 2014 FIGO Stage IIIA1 Subclassification for Ovarian, Fallopian Tube, and Peritoneal Cancers

Abstract

Background/aim: The 2014 International Federation of Gynecology and Obstetrics (FIGO) classification subdivides patients with stage IIIA1 ovarian, fallopian tube, and peritoneal cancers by the greatest dimension of metastatic lymph node without supporting evidence. This study aimed to assess the validity of this subdivision.

Patients and methods: A retrospective single-institution cohort study was performed in patients with ovarian, fallopian tube, or peritoneal cancer from 2009 to 2020. We compared outcomes between patients diagnosed with IIIA1(i) (metastasis ≤10 mm in the greatest dimension) and IIIA1(ii) (metastasis >10 mm in the greatest dimension).

Results: Of the 895 patients, 46 (5.1%) were classified as stage IIIA1, 20 as IIIA1(i), and 26 as IIIA1(ii). In stage IIIA1(ii), there were significantly more cases of serous carcinoma (p<0.001), and the number of positive nodes and lymph node ratio were significantly higher than those in stage IIIA1(i) (p=0.001, p=0.002). Five-year progression-free survival was 68.7% in patients with stage IIIA1(i) cancer and 58.1% in those with stage IIIA1(ii) (p=0.58). Five-year overall survival was 83.1% in patients with stage IIIA1(i) cancer and 80.2% in those with stage IIIA1(ii) (p=0.44). Among other patient characteristics and pathologic findings, there were no prognostic factors for patients with stage IIIA1 cancer.

Conclusion: In this retrospective cohort study, further classification of FIGO stage IIIA1 cancer was not significantly associated with patient outcomes.

Keywords: FIGO; Ovarian cancer; fallopian tube cancer; lymph node metastasis; peritoneal cancer.