Personalized Therapy based on Several Parameters of Comprehensive Tumour Profiling: a Challenge in NEBC

Primary neuroendocrine breast cancer (NEBC) is a rare entity accounting for <0.1% of all breast carcinomas and <1% of all neuroendocrine tumours. In most cases, treatment strategies in NEBC are empirical in absence of prospective trial data on NEBC cohorts. Herein, we present two case reports diagnosed with anaplastic large and small cell NEBC. After initial therapies analogue to those of breast cancer (BC) or neuroendocrine cancers (NEC) had failed, comprehensive tumour profiling was applied, leading to individualized treatment options for both patients. Due to targetable mutations and important co-alterations, the PIK3-mTOR pathway was highlighted from different aspects in both patients. The epicrisis of the two patients exemplifies how to manage the challenge of rare and difficult to treat cancers and how new diagnostic tools contribute to medical management.