Incidence trends of vulvar squamous cell carcinoma in Italy from 1990 to 2015

Abstract

Objective: The incidence of vulvar squamous cell carcinoma has increased for decades in most Western countries - a trend virtually restricted to women aged <50 or 60 years. In southern Europe, conversely, the trends have been insufficiently studied. This article reports a study from Italy.

Method: Thirty-eight local cancer registries, currently covering 15,274,070 women, equivalent to 49.2% of the Italian national female population, participated. Invasive cancers registered between 1990 and 2015 with an International Classification of Diseases for Oncology, 3rd revision, topography code C51 and morphology codes compatible with vulvar squamous cell carcinoma (n = 6294) were eligible. Incidence trends were analysed using joinpoint regression models, with calculation of the estimated annual percent change (EAPC), and age-period-cohort models.

Results: Total incidence showed a regular and significant decreasing trend (EAPC, -0.96; 95% confidence interval (CI), -1.43 to -0.48). This was entirely accounted for by women aged ≥60 years (EAPC, -1.34; 95% CI, -1.86 to -0.81). For younger women, the EAPC between 1990 and 2012 was 1.20 (95% CI, 0.34 to 2.06) with a non-significant acceleration thereafter. This pattern did not vary substantially in a sensitivity analysis for the effect of geographic area and duration of the registry. The age-period-cohort analysis revealed a risk decrease in cohorts born between 1905 and 1940 and a new increase in cohorts born since 1945.

Conclusions: The decreasing trend observed among older women and the resulting decrease in total rate are at variance with reports from most Western countries. Age-period-cohort analysis confirmed a decreasing trend for earliest birth cohorts and an opposite one for recent ones.

Keywords: Age-period-cohort modelling; Incidence; Trend; Vulvar neoplasms.