Chemotherapy for breast cancer is a treatment that uses medicines to kill cancer cells. The medicines work by killing fast-growing cells. Cancer cells often grow quickly. Chemotherapy also is called chemo.

When it's used for early-stage breast cancer, chemotherapy is often given after surgery to lower the risk that the cancer will come back. Sometimes it's used before surgery to shrink a cancer and make a less invasive surgery possible. Chemo also can be used for advanced cancer. It may help slow the cancer's growth.

Not everyone with breast cancer needs chemotherapy. Breast cancer treatment is different for each person. Your healthcare team looks at the type of cancer you have, its stage and your overall health when deciding whether chemotherapy should be part of your treatment plan. A member of your care team can explain why chemotherapy is or isn't recommended for your specific cancer.

Many people who have chemotherapy also have other breast cancer treatments. These may include surgery, radiation therapy and other medicines. Other medicines used to treat breast cancer work in different ways. Estrogen blocker therapy, which sometimes is called breast cancer hormone therapy, works against cancers that use hormones to grow. Targeted therapy works against specific proteins that help cancer cells grow.

Chemotherapy for breast cancer is used to treat the cancer or slow its growth. For early-stage breast cancer, it's often used before or after surgery to remove the cancer. If the cancer is advanced and surgery isn't an option, chemotherapy may be the main treatment.

Adjuvant therapy: Chemotherapy after surgery

Adjuvant chemotherapy is chemotherapy given after surgery, such as after a mastectomy. Using the treatment in this way may:

• Kill any cancer cells that remain after surgery.
• Lower the risk that the cancer will come back.

Adjuvant chemotherapy is often used for:

• Cancer that has grown large.
• Cancer that has a higher risk of coming back based on genomic testing results.
• Cancer that has spread to the lymph nodes.
• Cancer that is high grade.
• Triple-negative breast cancer.

Neoadjuvant therapy: Chemotherapy before surgery

Neoadjuvant chemotherapy is chemotherapy given before surgery. It also is called preoperative chemotherapy. Using the treatment in this way may:

• Shrink the cancer in the breast. Then an operation that is less invasive may be possible.
• Give the surgeon a better chance of removing the cancer completely.
• Lower the amount of cancer in the lymph nodes. This means fewer lymph nodes may need to be removed.
• Show whether the chemotherapy is working.
• Help the healthcare team choose the next treatment.

Neoadjuvant therapy is often used for:

• Cancer that has grown large.
• Cancer that has spread to the lymph nodes.
• HER2-positive breast cancer.
• Inflammatory breast cancer.
• Triple-negative breast cancer.

Primary therapy: Chemotherapy as the main treatment

Chemotherapy and other medicines often are the main treatments for advanced breast cancers that can't be removed with surgery. This includes cancer that spreads to other parts of the body, called metastatic breast cancer. Using the treatment in this way may:

• Slow the growth of the cancer.
• Reduce side effects, such as pain.
• Extend life.

The main goal of chemotherapy for advanced breast cancer is generally to improve quality and length of life rather than to cure the disease.

Who needs chemo and who doesn't?

Not everyone with breast cancer has chemotherapy. When deciding whether to include chemo in your treatment plan, your healthcare team may consider many things about your cancer, such as:

• Cancer grade. High-grade cancers are more likely to be treated with chemotherapy.
• Cancer size. Larger cancers are more likely to be treated with chemotherapy.
• Cancer type. Chemotherapy is used to treat all types of breast cancer. The types most likely to have this treatment include inflammatory breast cancer, HER2 positive breast cancer and triple-negative breast cancer.
• Genomic testing results. Genomic tests, such as Oncotype DX and MammaPrint, look at patterns of genes inside cancer cells to help estimate the risk that a cancer will come back. If it's not clear whether you might benefit from chemotherapy, your healthcare team might use a genomic test. These tests aren't helpful for everyone. They're only used in certain situations.
• Lymph node status. Chemotherapy is often used for cancer that has spread to the lymph nodes.
• Your overall health. Having other serious health conditions may affect your ability to tolerate side effects of chemotherapy. Certain conditions, such as heart disease or diabetes, may affect which medicines you receive.

Chemotherapy isn't a common treatment for noninvasive breast cancer, also called ductal carcinoma in situ.

Chemotherapy has risks. This treatment works by killing fast-growing cells, including cancer cells. But some healthy cells also grow quickly, so these cells might be hurt by the treatment. This can cause side effects.

Whether you have side effects depends on which medicines you receive. Most side effects are not long lasting. They may get better once you finish treatment. Sometimes chemotherapy can have long-term effects or cause changes that don't go away.

Short-term side effects

Short-term side effects often go away after treatment is finished. Common short-term side effects include:

• Constipation or diarrhea.
• Fatigue.
• Hair loss.
• Higher risk of infection.
• Joint and muscle pain.
• Mouth sores.
• Nausea and vomiting.
• Skin and nail changes.

Long-term side effects

Some side effects last a long time or do not go away. Long-term side effects can include:

• Chemo brain. The changes in thinking and memory that can happen in people with cancer are commonly called chemo brain. But these changes have many possible causes in addition to chemotherapy. Memory and thinking changes may improve with time, but sometimes they are long-lasting.
• Damage to the ovaries. In those who haven't been through menopause, chemotherapy medicines may hurt the ovaries. This can cause infertility and make it more difficult to become pregnant. Some people stop having their periods during chemotherapy. Periods may start again after treatment ends. Sometimes, chemotherapy causes early menopause. Menopause can cause hot flashes, vaginal dryness and other symptoms.
• Heart damage. Some chemotherapy medicines may raise the risk of a weakened heart and other heart conditions.
• Nerve damage. Some chemotherapy medicines cause damage to nerves in the fingers and toes. This condition, called peripheral neuropathy, causes pain, tingling and numbness. For many, the symptoms get better in the weeks and months after chemotherapy ends. For some, nerve damage is lasting.
• Other cancers. Rarely, chemotherapy for breast cancer can cause another kind of cancer. It may be diagnosed months to years after the chemotherapy is completed. Often this other cancer is a type of cancer of the blood cells, such as leukemia.

How are chemo side effects managed?

Your healthcare team may recommend ways to limit some side effects during treatment. Be sure to tell your team about any side effects that happen. Your care team can treat or help you manage many side effects.

• Coping with fatigue. Many people have fatigue during chemotherapy. It may feel like tiredness that doesn't get better with rest. Fatigue has many possible causes. Your healthcare team figures out and treats what might be causing your fatigue. To cope, it may help to save your energy for what's most important to you. It also may help to do gentle exercise, but talk with your healthcare team first. The team can make sure exercise is safe for you.
• Coping with hair loss. The most common chemotherapy medicines used for breast cancer are very likely to cause complete hair loss. Hair often starts thinning after the second or third infusion and continues through the end of treatment. You may choose to wear wigs, scarves or other head coverings. Scalp cooling may help lower the risk of losing all of the hair on your head. This involves wearing a cap filled with chilled water during infusions. Talk with your healthcare team about your options.
• Coping with mouth sores. If your medicines are likely to cause mouth sores, your care team may recommend swishing ice chips in your mouth during your infusion. This helps lower the risk. If mouth sores happen, medicines can help relieve pain and other symptoms. These medicines may include magic mouthwash and other treatments.
• Coping with nerve damage. If your chemotherapy medicines are likely to cause peripheral neuropathy, your care team might recommend cold therapy to lower the risk. This may involve wearing gloves and socks that hold ice or frozen gel packs. Talk with your care team about the options. Medicines may help if you get peripheral neuropathy symptoms.

To prepare for breast cancer chemotherapy, learn what side effects to expect and make plans for how treatment may affect your daily life. You also may need to have a chemo port or another venous access device placed. Your healthcare team can tell you which steps you need to take before treatment starts.

Plan ahead for side effects

Ask your healthcare team what side effects to expect during and after chemotherapy. Knowing what to expect may help you prepare. For example, if your chemotherapy medicines may cause infertility, talk with your team about fertility preservation options. You may wish to store sperm or eggs for future use. If your medicines may cause hair loss, you might ask about things you can do to help manage it. Consider a wig or a head covering.

Make arrangements for help at home and at work

Many people continue working and doing their usual activities during chemotherapy. Your healthcare team can give you an idea of how much treatment may affect your usual activities. But it's hard to predict just how you might feel.

One way to plan is to assume you may need help or time off from any usual duties in the first few days after treatment. You might choose to ask for time off from work. You might ask someone to help with tasks at home. Once you know how chemotherapy affects you, you can decide whether to continue these changes to your routine.

Tell your care team about any medicines or supplements you take

Medicines and supplements may affect the way the chemotherapy works. Tell your healthcare team if you're taking any prescription medicines or medicines you can buy without a prescription. Also tell the care team about any herbal supplements or vitamins that you take.

Have a chemo port placed

A chemo port or other central venous access device can make it easier to get chemotherapy medicines. These devices let your healthcare team put medicines into the large veins in your chest. When you have this type of device, you don't need a needle placed into a vein in your arm each time you have treatment. Other types of central venous access devices include peripherally inserted central catheters and central lines.

Your healthcare team talks with you about whether your treatment plan calls for one of these devices. The decision might be based on the medicines you'll receive, how long your infusions will last and how often you'll have treatments.

Chemotherapy for breast cancer most often involves having an infusion. This means the medicines go into a vein. Some medicines come in pill form, but these are only used in some situations.

Chemo infusions often happen in a hospital or clinic. For breast cancer, chemotherapy sessions usually are outpatient procedures, which means you go home after each treatment is done.

Chemotherapy is given in cycles. Some people may have infusions every week or two. Others may have chemotherapy every three or four weeks. How often you need to go in for treatment depends on the medicines you receive.

The cycles may repeat a set number of times. Chemo can last a few months to a year or more. When the treatment is used for metastatic breast cancer, it might continue for as long as the medicines keep working.

Before chemotherapy

Follow any instructions from your healthcare team about how to prepare on the day of your chemotherapy session. It may help to take a family member or friend with you to the treatment session for support and companionship.

Before a chemo infusion, you might first:

• Have a blood sample drawn for a blood count and other blood tests.
• Have a physical exam to check your temperature, pulse and blood pressure.
• Meet with your healthcare professional to review your test results and check your overall health.

If your care team decides that you can have treatment, your chemotherapy infusion may begin.

Sometimes, treatments need to be adjusted or stopped. This can occur when blood counts drop too low or other serious side effects happen. Treatments may start again when these side effects improve.

During chemotherapy

What happens during a chemotherapy infusion may depend on the medicines you're getting. In general, you can expect to:

• Have a needle connected to a thin tube inserted into a vein. The medicine goes through the tube and into your body. How the care team does this depends on your situation. The tube may go into a vein in your arm or into a port that connects to the veins in your chest.
• Receive medicines that help prevent side effects.
• Receive the chemotherapy medicines.

After chemotherapy

Following a chemotherapy session, you may:

• Have the tube that gives the medicines removed.
• Learn which side effects to expect, how to manage them and when to contact your care team.
• Receive prescriptions for medicines you can take at home to help with side effects.
• Receive instructions on how to safely handle body fluids, such as urine, stool, vomit, semen and vaginal secretions. Your body fluids may contain some of the chemotherapy medicines for the next 48 hours.

Some people feel fine after a chemotherapy session and can return to their schedules and activities. Others may feel side effects more quickly.

It may take some time before you know the results of chemotherapy for breast cancer. You may have tests to see whether the treatment is working. Ask your healthcare team when you will know the results.