Alternative Treatment Positions over Supine in Adjuvant Whole Breast RT: Prone, Lateral or What Else? A Comprehensive Narrative Review.

Whole breast radiotherapy in adjuvant breast cancer (BC) treatment has been commonly delivered in supine positioning for more than 50 years. Its widespread use is related to the broad availability of simple and common breast board immobilization devices, which exploit the natural recumbent position of the body with arms above the head, the good match with linac tables and well-established set up procedures. However, in scenarios like painful arm discomfort in patients with post-surgery arm or arthritic limitation, unfavorable chest geometry like pectus excavatum (PE), large and pendulous breasts in obese women and cardiac morbidity in left sided BC, supine position seems very uncomfortable for patients and troublesome for radiation oncologists. The question is how to proceed when supine IMRT or DIBH are ineffective strategies? Alternative positions have been analyzed over the past twenty years, starting with a lot of trials testing prone positioning variants with and without DIBH, lateral decubitus or upright standing radiotherapy. A better recognition of new treatment position options in BC adjuvant therapy may provide more opportunities for personalized radiotherapy in this population, to ensure they receive an appropriate, safe and comfortable treatment.