The role of postoperative radiotherapy in eccrine porocarcinoma: a multidisciplinary systematic review

OBJECTIVE: Eccrine porocarcinoma (EPC) is a malignant adnexal tumor accounting for about 0.005% of skin tumors. The standard treatment of EPC is the complete surgical excision of the primary lesion and of the clinically involved lymph nodes. There is limited evidence regarding the role of radiotherapy (RT) in managing EPC after surgery. Therefore, the aim of this multidisciplinary systematic review is to analyze the available evidence about postoperative RT in the curative treatment of EPC. MATERIALS AND METHODS: A systematic search strategy was launched trough the main scientific databases including PubMed, Scopus and Cochrane. An additional manual search and a chain citation were performed about potentially relevant papers. The key words used for the search included "eccrine porocarcinoma", "porocarcinoma", "radiotherapy", "radiation therapy", "adjuvant radiotherapy" and "postoperative radiotherapy". RESULTS: A total of 104 publications were identified and 14 papers were included in the final analysis. The only articles found on adjuvant RT in EPC were case reports published between 1996 and 2019. There was a slight female prevalence (57% female/43% male) with a mean age of 65 years (range 37-85). Head-andneck region was the most frequently involved anatomical site followed by legs. CONCLUSIONS: Adjuvant radiotherapy after surgical removal of EPC could be considered in cases with positive or close margins and in cases with unfavorable histological features. In view of limited literature data and the rarity of EPC the best treatment sequence should always be discussed within the frame of a multidisciplinary setting. Advances in knowledge: adjuvant radiotherapy after surgical removal of EPC could be considered in cases with positive or close margins and in cases with unfavorable histological features.