The problem is that both normal cells and cancer cells have these same parts. Chemotherapy can affect many cells throughout the body, including normal cells. It is not as selective in regards to the cells it attacks. This may lead to more side effects compared to hormonal(HORE-MOAN-OL THAIR-AH-PEE) — Anticancer medication used to target estrogen and progesterone receptors and targeted therapy(TAR-GET-TED THAIR-AH-PEE) — Anticancer medication that attaches to a specific protein receptor and blocks the receptor’s normal function. But the benefit of chemotherapy is that it can work fast to shrink and kill cancers.