Changes in clinico-pathological characteristics of vulvar cancer in Japan: Increasing oldest-old, stage-shifting, and decreasing cohort-level survival

Background Vulvar cancer is a rare malignancy. Its occurrence in Japan is 1/6-1/10 of that in the Western countries. Population-based statisics for vulvar cancer has been missing in Japan. To examine trends in clinico-pathological characteristics of vulvar cancer in Japan. Methods This is a nationwide retrospective study examining consecutive cases of women with invasive vulvar cancer in Japan between 2001-2010 (n = 1,061). Temporal trends of demographics, tumor characteristics, and survival outcome were assessed with cohort-level analysis. The National Cancer Institute’s Surveillance, Epidemiology, and End Result Program served as the external validation (n = 10,154). Results The number of oldest-old women aged ≥80 years significantly increased from 18.0% to 30.6% (70.5% relative increase) over time. There was a stage-shift observed, and stage I disease decreased from 43.0% to 34.0% (21.0% relative decrease) whereas tumors with inguino-femoral nodal or distant metastasis increased from 23.2% to 35.6% (53.3% relative increase) during the study period (P 0.05). Conclusions Demographics and outcomes of vulvar cancer in Japan have significantly changed during the study period: Increasing oldest-old population and stage-shift to more metastatic disease resulted in cohort-level decrease in survival rates. Legal entity responsible for the study The authors. Funding Has not received any funding. Disclosure All authors have declared no conflicts of interest.