Validation of the 2021 FIGO vulvar cancer staging schema (567)

Abstract

Objectives: The International Federation of Gynecology and Obstetrics (FIGO) revised the cancer staging schema of vulvar cancer in 2021. Major changes to stage III-IV diseases included: (i) prior stage IIIA-B diseases were re-classified based on nodal size (<5mm for stage IIIA vs >5mm for stage IIIB), and (ii) prior stage IVA1 disease based on non-osseous organ extension was re-classified to stage IIIA. This study sought to validate the 2021 FIGO vulvar cancer staging schema. Methods: This retrospective cohort study examined 889 women with stage III-IV vulvar cancer from 2010-2015 in the Surveillance, Epidemiology, and End Results Program. Stage-shift and overall survival (OS) were assessed, comparing the 2021 and 2009 FIGO staging schemas. Results: Stage-shift occurred in 229 (25.8%) cases: upstaging in stage IIIA (54.1%), downstaging in stage IIIB (7.5%), and downstaging in stage IVA (45.3%) diseases. When comparing the new and prior staging schemas, 5-year OS rates were 45.6% versus 48.9% for stage IIIA, 47.0% versus 44.2% for stage IIIB, and 13.9% versus 25.1% (interval change: -11.2%) for stage IVA disease. According to the revised staging schema, 5-year OS rates were similar between stage IVA and IVB diseases (13.9% vs 14.5%, p=0.221) and between stage IIIA and IIIB disease (45.6% vs 47.0%, p=0.997). For new stage IIIA disease, 5-year OS rates differed significantly based on the staging factors (nodal involvement vs non-nodal organ involvement, 48.9% vs 38.7%, difference 10.2%, p=0.038). Conclusions: The 2021 FIGO staging schema is useful to distinguish survival in advanced vulvar cancer. Survival of new stage IVA disease appears to be comparable to stage IVB disease. Survival of new stage IIIA disease is heterogeneous based on the nodal versus non-nodal organ involvements. Objectives: The International Federation of Gynecology and Obstetrics (FIGO) revised the cancer staging schema of vulvar cancer in 2021. Major changes to stage III-IV diseases included: (i) prior stage IIIA-B diseases were re-classified based on nodal size (<5mm for stage IIIA vs >5mm for stage IIIB), and (ii) prior stage IVA1 disease based on non-osseous organ extension was re-classified to stage IIIA. This study sought to validate the 2021 FIGO vulvar cancer staging schema. Methods: This retrospective cohort study examined 889 women with stage III-IV vulvar cancer from 2010-2015 in the Surveillance, Epidemiology, and End Results Program. Stage-shift and overall survival (OS) were assessed, comparing the 2021 and 2009 FIGO staging schemas. Results: Stage-shift occurred in 229 (25.8%) cases: upstaging in stage IIIA (54.1%), downstaging in stage IIIB (7.5%), and downstaging in stage IVA (45.3%) diseases. When comparing the new and prior staging schemas, 5-year OS rates were 45.6% versus 48.9% for stage IIIA, 47.0% versus 44.2% for stage IIIB, and 13.9% versus 25.1% (interval change: -11.2%) for stage IVA disease. According to the revised staging schema, 5-year OS rates were similar between stage IVA and IVB diseases (13.9% vs 14.5%, p=0.221) and between stage IIIA and IIIB disease (45.6% vs 47.0%, p=0.997). For new stage IIIA disease, 5-year OS rates differed significantly based on the staging factors (nodal involvement vs non-nodal organ involvement, 48.9% vs 38.7%, difference 10.2%, p=0.038). Conclusions: The 2021 FIGO staging schema is useful to distinguish survival in advanced vulvar cancer. Survival of new stage IVA disease appears to be comparable to stage IVB disease. Survival of new stage IIIA disease is heterogeneous based on the nodal versus non-nodal organ involvements.