Case report: Prone positioning contributes to dose restriction of risk organs in a patient with an an extramedullary manifestation of myeloma in the breast

Introduction With regards to the deterministic and stochastic mutation risk, the protection of organs at risk plays a critical key role in radiotherapy, particularly in curative intention in the treatment of young patients. In this context, correct positioning of the patient can make an important contribution to reduce the radiation dose applied to critical tissues and organs at risk. In this clinical case, we would like to demonstrate how correct and advanced positioning in modern radiotherapy significantly reduces the dose applied to surrounding tissues and organs at risk in a patient with extramedullary myeloma. Method A 42-year-old female patient presented with a sole extramedullary involvement of a myeloma in the upper outer quadrant of the left breast. There was no evidence of serological or medullary disease activity. Radiotherapy was applied to the left breast in the prone position with a cumulative dose of 50 Gy in 25 fractions. Results By positioning the patient in prone position, radiotherapy was planned without exposing the organs at risk to relevant doses. Moreover, there was no indication of increased toxicity of the skin or mammary gland tissue Grade II° (CTCAE) or higher. Discussion This case report demonstrates how positioning can influence the protection of surrounding normal tissue and organs at risk.