The difference between 61 treatment recommendations from the LLM and the 48 from the MTB underlines the LLM’s over-recommendation tendency, which ultimately may lead to overtreatment and lack of individualized treatment decision making, i.e., the chatbot recommended endocrine treatment for all DCIS profiles (P17-P19), as well as situations with low ER and PR positivity (P16 and P9), for invasive breast cancer, which are can-do decisions but not necessarily must-do. Here, ESR1 is linked to ductal breast carcinoma in situ.