Postoperative Radiation Therapy after Nipple-Sparing or Skin-Sparing Mastectomy: A Survey of European, North American, and South American Practices.

Skin sparing mastectomy, a surgical procedure sparing a large portion of the overlying skin of the breast, and nipple-sparing mastectomy, sparing the whole nipple-areolar complex, are increasingly used, although their oncologic efficacy remains unclear. The aim of this study was to assess the radiation oncologists' opinions regarding the indications of radiation therapy (RT) after skin-sparing mastectomy and nipple-sparing mastectomy. Radiation oncology members of four national and international societies were invited to complete a questionnaire comprising of 22 questions to assess their opinions regarding RT indications in the context of skin-sparing and nipple-sparing mastectomy. A total of 298 radiation oncologists answered the questionnaire. 90.9% of respondents affirmed that breast cancer is one of their specializations. The majority declared that post-mastectomy RT is indicated for early-stage (stages I and II) breast cancer patients who present with risk factors for recurrence after skin-sparing or nipple-sparing mastectomy (87.2% and 80.2%, respectively). All suggested risk factors (tumor size, lymph node involvement, extracapsular extension, lymphovascular space invasion, positive surgical margins, triple negative tumor, multicentric tumor, and age) were considered as major elements (important or very important). There is no consensus regarding the necessity of evaluating residual breast tissue or the definition of residual breast tissue after mastectomy. All classic factors were considered as major elements, potentially influencing the decision to advice or not postoperative RT. Many uncertainties remain about the indications for RT after skin-sparing mastectomy or nipple-sparing mastectomy.