In some cases, patients with breast cancer have to use specific medications that destroy the tumor. Chemotherapy involves a series of drugs that will stop the cancerous cells from growing and dividing. It can be administered via an intravenous tube (IV) or an oral capsule or pill. Not all breast cancer patients undergo chemotherapy as a treatment; it depends on the type and stage of cancer along with the likelihood of success. Your medical oncologist may suggest neoadjuvant or preoperative chemotherapy, which takes place before surgery. This allows the tumor to shrink in size and thereby, decreases the risks of surgery by making it easier to perform..