Fat necrosis of the breast in the accelerated partial breast irradiation era: the need for a universal grading system

Fat necrosis of the breast is increasingly reported and used as a trial endpoint in the treatment of breast cancer with accelerated partial breast irradiation (APBI). Yet, there is no universal toxicity scoring system within the latest version of the Common Terminology Criteria for Adverse Events (CTCAE v4.0). This requires investigators to adopt their own scoring system or improperly use those that exist, and limits accurate reporting of this entity. Fat necrosis of the breast also creates diagnostic uncertainty among clinicians and concern of recurrence among patients. In this review, we address the question of increasing incidence of fat necrosis through the comparison of recent APBI trials and literature. The pathogenesis, symptoms, clinical and radiologic diagnosis, clinical predictors of developing fat necrosis, management and follow-up are also discussed. Lastly, we propose a simplified and universal scoring system for the reporting of fat necrosis.