The burden of cutaneous adnexal carcinomas and the risk of associated squamous cell carcinoma: a population-based study.

BACKGROUND: Recent studies have shown an increasing incidence of cutaneous adnexal carcinomas (CACs) over the years.

OBJECTIVE: The aim of our study was to evaluate incidence and survival of CACsand investigate their association with other skin neoplasms.

METHODS: Population based study. Data on incident cases of CACs were obtained from the Tuscany Cancer Registry (TCR) between 1985 and 2010. In order to determine if the occurence of squamous cell carcinoma (SCC) among patients with CAC is higher or lower than expected in the general population, standardized incidence ratio (SIR) was calculated.

RESULTS: 242 patients with CAC were observed; age-standardized incidence rate was 3·8 cases per millionperson-years. From 1997 to 2010, crude-incidence rates increased by 159%. Age-specific incidence was higher in males over 80 year-oldthan females of the same age and younger individuals. Carcinomas of sweat gland originprevailed; the most common histotype was porocarcinoma and the most frequentlyaffected site was the head-neck. 88% of CACs was diagnosed at a localized stage. 5-year overall survival and disease-specific survival rates were 59% (95%CI 53-65) and 94% (95%CI 91-98), respectively. In observation cohort, number of SCC was significantly higher than expected as SIR resulted 33·7 (p<0·0001).

CONCLUSION: Increasing incidence warrants awareness and early diagnosis of cutaneous adnexal carcinomas. Increased SCC incidence among patients with these tumors highlights relevance of careful skin examination and follow-up. This article is protected by copyright. All rights reserved.