Validation of the FIGO 2018 staging system of cervical cancer: Retrospective analysis of FIGO 2009 stage IB1 cervical cancer with tumor under 2 cm

Aim: The International Federation of Gynecology and Obstetrics (FIGO) revised the cervical cancer staging system in 2018. This study aims to validate the revised staging system in patients with tumors <2 cm in size who were classified as FIGO 2009 stage IB1. Methods: We evaluated 62 women with stage IB1 cervical cancer (FIGO 2009) who underwent radical hysterectomy as the initial treatment between November 2004 and August 2018 in our institution. The patients with FIGO 2009 stage IB1 and tumors <2 cm in size were enrolled. We reclassified their stage according to the FIGO 2018 staging system and analyzed their clinicopathological data retrospectively. Results: Twenty-five patients met the inclusion criteria. According to the FIGO 2018 classification, 9 (36.0%) patients were classified as stage IA, 13 (52.0%) as stage IB1, and 3 (12.0%) as stage IIIC, respectively. One (11.1%), six (46.2%), and three (100%) patients with lymphovascular space invasion were classified as stage IA, IB1, and IIIC, respectively. No significant differences were found in the 5-year overall survival or progression-free survival among the three stages. Conclusions: As many as 36.0% of patients classified as FIGO 2009 stage IB1 with a tumor <2 cm in size were classified as stage IA in the FIGO 2018 classification. For these cases, a treatment less invasive than radical hysterectomy or radiotherapy might be sufficient. Our results suggest that cervical cancer patients with tumors <2 cm should be carefully diagnosed by performing cervical conization and assessed the pathological findings before hysterectomy.