Chemotherapy is part of the treatment for many cancers, including breast cancer. Because chemotherapy works by killing rapidly multiplying cells, in addition to killing cancer cells, it also kills healthy cells that divide quickly, like those in your mouth and intestines, and in your hair follicles, according to cancer.org. Side effects of breast cancer chemotherapy can depend on the drug regimen you are on, the dosing schedule and the dose of the drug. Many are transient and subside after treatment, but some can be long-term.
Reproductive System Side Effects
Chemotherapy can disrupt the menstrual cycle in women, and cause infertility and premature menopause. The effects of chemotherapy depend on the drugs that are used, the dosage and your age, according to the American Cancer Society. During chemotherapy, you may experience symptoms that resemble menopausal symptoms, like hot flashes, vaginal burning and itching, and dryness of vaginal tissues, according to cancer.org. In addition to a lowered libido, the physical changes in your vaginal tissues can make intercourse uncomfortable or painful but can be eased with a water-based lubricant. Although your periods may become erratic or stop completely during chemotherapy, it is still possible to become pregnant. Since chemotherapy can be toxic to a fetus, it is best to use birth control if you have not gone through menopause prior to the start of treatment.
Neurological Side Effects
Many women on chemotherapy for breast cancer describe something called "chemo brain". Chemo brain can include trouble concentrating, difficulty multi-tasking, having slower thinking and processing; generally feeling mental "cloudiness" (cancer.org). This tends to go away after a few years, and the majority of people are able to function normally after treatment ends, despite some chemo brain.
Some of the chemotherapy drugs used to treat breast cancer cause peripheral neuropathy, a condition in which nerves in the hands and feet are damaged, which can lead to feelings of "pins and needles," burning, temperature sensitivity and weakness. This usually subsides after treatment ends, but for some women it lasts much longer.
Heart Damage
The class of chemotherapy drugs known as anthracyclines are frequently used in the treatment of breast cancer. Adriamycin, also known as doxorubicin, a staple in many treatment regimens, is known to weaken the heart, as is epirubicin, according to health.nytimes.com. Herceptin, also called trastuzumab, has also been found to increase the risk of heart failure. While on treatment, your doctor will monitor you for any heart problems, and regular follow-up after treatment ends is recommended.
General Side Effects
Other side effects of chemotherapy for breast cancer include a slightly increased risk of later leukemia; low blood counts, which increases your risk for infection; hair loss; mouth sores; appetite changes, and fatigue, according to cancer.org. Fatigue is a very common side effect of cancer treatment, with approximately 70 to 100 percent of patients reporting the symptom during treatment, and up to half of patients reporting it after treatment has ended, even months to years later.
