Radiotherapy and prognostic factors in adnexal carcinomas: A retrospective study of 657 patients from the French CARADERM network.

Background: Cutaneous adnexal carcinomas are a heterogeneous group of rare neoplasms. Surgical excision is the first-line treatment in localized stage. The use and effectiveness of radiotherapy have not been thoroughly evaluated in these neoplasms.
Objectives: The present work analyses prognostic factors on outcomes in skin adnexal carcinomas, based on data from the CARADERM (CAncers RAres DERMatologiques) database.
Methods: Data were collected retrospectively including demographic data, tumour types and therapeutic characteristics of all patients included in the CARADERM database, with at least one informative follow-up visit. Analyses were performed on three populations: patients with complete resection of the primary tumour (ADJ/primary population), patients achieving complete remission after complete resection of a recurrent tumour (ADJ/recurrent population) and patients with unresectable locally advanced or metastatic tumours (ADV/MET population). Overall and recurrence/progression-free survivals at 3-year were analysed using Cox regression models.
Results: Radiotherapy did not affect overall survival (OS) in the ADJ/primary population. Adjusted recurrence-free survival (RFS) was significantly lower in the radiotherapy group in ADJ/primary group. Older patients had significantly poorer OS and RFS. Tumour size and immunosuppression were significantly associated with poorer RFS only. Radiotherapy had no effect on OS and RFS in the ADJ/recurrent population. Age was the only factor associated with a poorer OS. Radiotherapy was significantly associated with longer progression-free survival (PFS) in age-sex adjusted analysis in the ADV/MET population, without effect on OS.
Conclusions: Our study shows that age, tumour size and immunosuppression are significantly associated with survival in localized adnexal carcinomas. Radiotherapy may improve PFS in the ADV/MET population but not in localized and recurrent carcinomas after complete excision.
(© 2024 The Author(s). Journal of the European Academy of Dermatology and Venereology published by John Wiley & Sons Ltd on behalf of European Academy of Dermatology and Venereology.)