There are certain breast cancer situations where treatment is routinely given before surgery. That treatment could be chemotherapy or it could be endocrine therapy. Typically the sequence of breast cancer treatment does’t effect the ultimate outcome with regards to cancer control rate or survival. Doing surgery first doesn’t give an advantage in cure rate. Sometimes chemotherapy is given before mastectomy if the cancer is large and/or if there are significant size and number of lymph nodes already involved. This allows for a better operation if cancer shrinkage is needed to close the skin flaps and also better timing if immediate reconstruction is planned. Getting a breast surgeon and a plastic surgeon and 3–4 or more hours of operating room time that isn’t scheduled quickly, given that the best surgeons are also the ones in greatest demand and usually booked out a number of weeks and even months, could be costly. Certain kinds of breast cancer usually get chemotherapy before surgery. HER2 positive breast cancers get an immunotherapy (Herceptin) with chemotherapy. Triple negative breast cancers usually get chemotherapy before surgery. This statement does not apply if the cancers are small and lymph nodes appear normal. Some estrogen receptor (ER) positive, or progesterone receptor (PR) positive breast cancers are treated with endocrine therapy before lumpectomy if shrinkage of the cancer will permit a better outcome in terms of clear margins and better cosmetic appearance. All of these pre-operative treatments are usually given for about 5–6 months before surgery. This question originally appeared on Quora - Source
