Final answer:
A surgical biopsy is essential before breast cancer treatment for a definitive diagnosis, identifying the cancer type and stage. Genetic testing may also be conducted for BRCA mutations, assisting in future care and familial risk assessment.
Step-by-step explanation:
Before initiating breast cancer treatment, it's crucial to perform a surgical biopsy. A biopsy provides definitive cancer diagnosis by examining tissue samples microscopically. This procedure not only confirms the presence of cancer but also reveals the type and stage of cancer, which are vital for formulating an effective treatment plan. Genetic testing may also be recommended to detect mutations in genes like BRCA1 and BRCA2, which can help assess risk in the patient's relatives and guide future medical care.