Your doctor determines which chemicals to use based on your type of cancer, age, general health and perceived ability to handle various side effects. Methotrexate belongs to the group of medicines known as antimetabolites. It works by blocking an enzyme needed by the cancer cell to live. Paclitaxel is a relatively new anticancer agent that initially was derived from the bark of the Pacific yew tree. Cancer cells can be destroyed, but so will many other types of cells, including hair cells, bone marrow cells and those that line the digestive tract.
Side effects vary depending on the drugs used.
They often are more severe with higher doses and may become stronger during the course of treatment. However, medications can be taken to relieve some of these symptoms, and nearly all side effects are reversible when treatment ends. In addition, many people are able to pursue normal activities for all but the day or two a month surrounding their treatment. Though side effects can be temporarily debilitating, the reason that so many women receive chemotherapy is that it can benefit many breast cancer patients, regardless of age. The presence of the hormone estrogen affects the growth of as many as two-thirds of all breast cancers, and the hormone progesterone similarly affects 40 percent to 50 percent of all breast cancers, according to the National Cancer Institute.