2672 - 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). The number of women who underwent surgical treatment decreased from 84.0% to 69.7% (17.0% relative decrease) whereas utilization of radiotherapy increased from 34.4% to 43.2% (25.7% relative increase) over time (P < 0.05). In the cohort-level analysis, the 5-year survival rates significantly decreased between 2001-2010 (P < 0.05): 66.9% to 51.0% for progression-free survival (23.7% relative decrease), 79.5% to 67.9% for cause-specific survival (14.6% relative decrease), and 74.9% to 62.3% for overall survival (16.9% relative decrease). In the patient-level analysis, oldest-old women were less likely to undergo surgical treatment and independently associated with decreased survival (all, P < 0.05). In the US cohort, the number of oldest-old women (25.2% to 27.8%) and the 5-year cause-specific survival rate (81.8% to 79.9%) stayed unchanged during the study period (all, 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.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.