Chemotherapy (chemo) is treatment with cancer-killing drugs that may be given intravenously (injected into a vein) or by mouth. The drugs travel through the bloodstream to reach cancer cells in most parts of the body.
When is chemotherapy used?
Not all women with breast cancer will need chemo, but there are several situations in which chemo may be recommended:
After surgery (adjuvant chemotherapy): Adjuvant chemo is used after surgery to try to kill any cancer cells that may have been left behind or spread but can’t be seen, even on imaging tests. If these cells were allowed to grow, they could form new tumors in other places in the body. Adjuvant chemo can reduce the risk of breast cancer coming back.
Before surgery (neoadjuvant chemotherapy): Neoadjuvant chemo is given before surgery. It can be used to try to shrink the tumor so that it can be removed with less extensive surgery. Because of this, neoadjuvant chemo is often used to treat cancers that are too big to be removed at the time of diagnosis (called locally advanced cancers). Also, by giving chemo before the tumor is removed, doctors can better see how the cancer responds to it. If the first set of chemo drugs doesn’t shrink the tumor, your doctor will know that other drugs are needed.
For advanced breast cancer: Chemo can be used as the main treatment for women whose cancer has spread outside the breast and underarm area, either when it is diagnosed or after initial treatments. The length of treatment depends on how well the chemo is working and how well you tolerate it.
Which chemotherapy drugs are used for breast cancer?
In most cases (especially as adjuvant or neoadjuvant treatment), chemo is most effective when combinations of more than one drug are used. Today, doctors use many different combinations, and it’s not clear that any single combination is clearly the best.
The most common drugs used for adjuvant and neoadjuvant chemo include:
Anthracyclines, such as doxorubicin (Adriamycin) and epirubicin (Ellence)
Taxanes, such as paclitaxel (Taxol) and docetaxel (Taxotere)
Most often, combinations of 2 or 3 of these drugs are used.
Chemotherapy for advanced breast cancer
Chemo drugs useful in treating women with breast cancer that has spread include:
Platinum agents (cisplatin, carboplatin)
Liposomal doxorubicin (Doxil)
Albumin-bound paclitaxel (nab-paclitaxel or Abraxane)
Although drug combinations are often used to treat early breast cancer, advanced breast cancer is more often treated with single chemo drugs. Still, some combinations, such as carboplatin or cisplatin plus gemcitabine, are commonly used to treat advanced breast cancer.
For cancers that are HER2-positive, one or more drugs that target HER2 may be used with chemo. (See Targeted therapy for breast cancer for more information about these drugs.)
How is chemotherapy given?
Chemo drugs for breast cancer are typically given into a vein (IV), either as an injection over a few minutes or as an infusion over a longer period of time. This can be done in a doctor’s office, chemotherapy clinic, or in a hospital setting.
Doctors give chemo in cycles, with each period of treatment followed by a rest period to give the body time to recover from the effects of the drugs. Cycles are most often 2 or 3 weeks long. The schedule varies depending on the drugs used. For example, with some drugs, the chemo is given only on the first day of the cycle. With others, it is given for a few days in a row, or once a week. Then, at the end of the cycle, the chemo schedule repeats to start the next cycle.
Adjuvant and neoadjuvant chemo is often given for a total of 3 to 6 months, depending on the drugs used. The length of treatment for advanced breast cancer is based on how well it is working and what side effects you have.
Doctors have found that giving the cycles of certain chemo drugs closer together can lower the chance that the cancer will come back and improve survival for some women. For example, a drug that would normally be given every 3 weeks might be given every 2 weeks. This approach can be used for neoadjuvant and adjuvant treatment. It can lead to more problems with low blood cell counts, so it’s not an option for all women.
Possible side effects of chemo for breast cancer
Chemo drugs can cause side effects. These depend on the type and dose of drugs given, and the length of treatment. Some of the most common possible side effects include:
Loss of appetite or increased appetite
Nausea and vomiting
Chemo can affect the blood-forming cells of the bone marrow, which can lead to:
Increased chance of infections (from low white blood cell counts)
Easy bruising or bleeding (from low blood platelet counts)
Fatigue (from low red blood cell counts and other reasons)
These side effects usually go away after treatment is finished. There are often ways to lessen these side effects. For example, drugs can be given to help prevent or reduce nausea and vomiting.
Other side effects are also possible. Some of these are more common with certain chemo drugs. Ask your cancer care team about the possible side effects of the specific drugs you are getting.
Nerve damage (neuropathy)
Many drugs used to treat breast cancer, including the taxanes (docetaxel and paclitaxel), platinum agents (carboplatin, cisplatin), vinorelbine, eribulin, and ixabepilone, can damage nerves outside of the brain and spinal cord. This can sometimes lead to symptoms (mainly in the hands and feet) like numbness, pain, burning or tingling sensations, sensitivity to cold or heat, or weakness. In most cases this goes away once treatment is stopped, but it might last a long time in some women. (See Peripheral Neuropathy Caused By Chemotherapy.)
Certain chemo drugs, such as capecitabine and liposomal doxorubicin, can irritate the palms of the hands and the soles of the feet. This is called hand-foot syndrome. Early symptoms include numbness, tingling, and redness. If it gets worse, the hands and feet can become swollen and uncomfortable or even painful. The skin may blister, leading to peeling or even open sores. There is no specific treatment, although some creams may help. These symptoms gradually get better when the drug is stopped or the dose is lowered. The best way to prevent severe hand-foot syndrome is to tell your doctor when early symptoms come up, so that the drug dose can be changed.
Many women who are treated for breast cancer report a slight decrease in mental functioning. They may have some problems with concentration and memory, which may last a long time. Although many women have linked this to chemo, it also has been seen in women who did not get chemo as part of their treatment. Still, most women function well after treatment. In studies that have found chemo brain to be a side effect of treatment, the symptoms most often last for a few years. (See Chemo Brain.)
Feeling unwell or tired (fatigue)
Many women do not feel as healthy after chemo as they did before. There is often a residual feeling of body pain or achiness and a mild loss of physical functioning. These may be very subtle changes that happen slowly over time.
Fatigue is another common problem for women who have received chemo. This may last up to several years. It can often be helped, so it’s important to let your doctor or nurse know about it. Exercise, naps, and conserving energy may be recommended. If you have sleep problems, they can be treated. Sometimes women become depressed, which may be helped by counseling and/or medicines. (See Fatigue.)
Doxorubicin, epirubicin, and some other chemo drugs may cause permanent heart damage (called cardiomyopathy). The risk is highest if the drug is used for a long time or in high doses.
Most doctors will check your heart function with a test like an echocardiogram (an ultrasound of the heart) or a MUGA scan before starting one of these drugs. They also carefully control the doses, watch for symptoms of heart problems, and may repeat the heart test during treatment. If the heart function begins to decline, treatment with these drugs will be stopped. Still, in some people, signs might not appear until months or years after treatment stops. Damage from these drugs happens more often if other drugs that can cause heart damage, such as drugs that target HER2, are used as well, so doctors are more cautious when these drugs are used together.
Menstrual changes and fertility issues
For younger women, changes in menstrual periods are a common side effect of chemo. Premature menopause (not having any more menstrual periods) and infertility (not being able to become pregnant) may occur and may be permanent. Some chemo drugs are more likely to cause this than others. The older a woman is when she gets chemotherapy, the more likely it is that she will go through menopause or become infertile as a result. When this happens, there is an increased risk of bone loss and osteoporosis. There are medicines that can treat or help prevent problems with bone loss.
Even if your periods have stopped while you are on chemo, you may still be able to get pregnant. Getting pregnant while on chemo could lead to birth defects and interfere with treatment. If you are pre-menopausal before treatment and are sexually active, it’s important to discuss using birth control with your doctor. For women with hormone receptor-positive breast cancer, some types of hormonal birth control (like birth control pills) are not a good idea, so it’s important to talk with both your oncologist and your gynecologist (or family doctor) about what options would be best in your case. Women who have finished treatment (like chemo) can safely go on to have children, but it’s not safe to get pregnant while on treatment.
If you are pregnant when you get breast cancer, you still can be treated. Certain chemo drugs can be taken safely during the last 2 trimesters of pregnancy. We have more details in our section on breast cancer during pregnancy.
If you think you might want to have children after being treated for breast cancer, talk with your doctor before you start treatment. Learn more from our section on fertility concerns for women with cancer.
Increased risk of leukemia
Very rarely, certain chemo drugs can cause diseases of the bone marrow, such as myelodysplastic syndrome or even acute myeloid leukemia, a cancer of white blood cells. When this happens it is usually within 10 years after treatment. For most women, the benefits of chemo in helping prevent breast cancer from coming back or in extending life are likely to far exceed the risk of this rare but serious complication.