When chemotherapy is your first treatment for cancer, it’s called neoadjuvant therapy. This method is often used for advanced breast cancer or large tumors that complicate surgery. It may also lower the risk of recurrence.

When chemotherapy is the first step in your breast cancer treatment, it’s called neoadjuvant therapy. Neoadjuvant therapies are systemic therapies that come before a main treatment.

Because there are several kinds of breast cancer, not everyone receives the same treatments in the same order. While neoadjuvant chemotherapy is a good option for some people with breast cancer, it’s not the best choice for everyone.

This article discusses neoadjuvant chemotherapy for breast cancer, when and how it’s used, and what you can expect from the treatment.

Neoadjuvant chemotherapy for breast cancer is given before your main treatment. In breast cancer, the main treatment is likely to be a mastectomy or a breast-conserving surgery (lumpectomy). Other possible treatments are hormone therapy and targeted therapies.

Neoadjuvant vs. adjuvant chemotherapy

Neoadjuvant therapy: Breast cancer typically requires more than one type of treatment. The primary treatment is usually surgery. When you have chemotherapy first, it’s called neoadjuvant therapy because it comes before the main treatment. The goal is to shrink the tumor. In some cases, this means you can have a less extensive surgery.

Adjuvant therapy: If you have chemotherapy after surgery, it’s called adjuvant therapy. This means it adds to the main treatment. The goal is to destroy the remaining cancer cells and reduce the risk of recurrence. Adjuvant systemic therapy is a common treatment for early-stage breast cancer.

Neoadjuvant chemotherapy for breast cancer may be beneficial if you have:

There’s a lot to consider, so the type of treatment is a case-by-case decision. To figure out whether you’re a good candidate, your oncology team will consider any other health concerns you may have.

In addition to a clinical examination, tests that can help inform the decision include:

These tests help determine key factors such as:

  • tumor type
  • grade (aggressiveness)
  • whether the cancer has invaded your lymphatic or vascular system
  • whether the cancer has spread to distant organs/sites (if it has, then surgery is not an option)

In addition to helping doctors decide the order of treatments, this information can help them determine which chemotherapy drugs are most likely to be effective.

If you cannot have surgery right away, neoadjuvant chemotherapy can get treatment started and help prevent cancer from spreading before you’re ready for surgery.

Shrinking a large tumor can also lower the risk of complications during surgery.

Other potential benefits are:

  • Evaluation of chemotherapy drugs: Your oncologist will monitor the size of the tumor. This makes it easier to see how well chemotherapy is working. If the tumor isn’t shrinking, you can quickly switch to a different drug.
  • Lower risk of recurrence: Because chemotherapy is a systemic therapy, it can also kill cancer cells that may have entered your lymphatic or vascular system. This can lower the risk of recurrence.
  • Less invasive surgery: Shrinking the tumor may make it possible for you to have breast-conserving surgery rather than a mastectomy. In some cases, neoadjuvant chemotherapy may eliminate the need for surgery.
  • More time to plan: Starting with chemotherapy gives you more time for genetic testing and making decisions about breast cancer surgery and reconstructive surgery.

The specifics of chemotherapy vary from person to person. Aside from the timing, the basic procedures for neoadjuvant and adjuvant chemotherapy are the same.

Chemotherapy is given in cycles. One treatment, or infusion, is sometimes called a “round.” Most neoadjuvant chemotherapy regimens are given intravenously.

After a chemotherapy infusion, you have a rest period to allow your body to recover. The infusion and rest period together are referred to as one cycle. Your next infusion starts a new cycle.

A single infusion can take several hours. The length of a chemotherapy cycle for breast cancer varies but is usually 2 or 3 weeks.

The number of infusions and the rest period length depend on the drug or combination of drugs and how well it works. If you experience severe side effects, you might need a longer rest before the next round. This can extend your overall treatment time.

Neoadjuvant chemotherapy can last 3 to 6 months. Imaging tests will help your care team evaluate the response. With a good response, you may be able to schedule surgery within a few weeks of your last cycle.

Although neoadjuvant and adjuvant chemotherapy have the same side effects, many of the side effects will depend on the specific drugs, doses, and number of cycles.

While the list of potential side effects is long, you probably won’t have them all. Possible side effects of chemotherapy include:

  • fatigue
  • hair loss and nail changes
  • appetite loss and weight changes
  • nausea and vomiting
  • diarrhea or constipation
  • mouth sores
  • easy bruising and bleeding
  • risk of infection
  • menstrual cycle changes
  • a slight decrease in mental function, commonly known as “chemo brain”

Most of these side effects will begin to fade when treatment ends. Some potential longer term side effects include:

Immunotherapy may be given with neoadjuvant chemotherapy

In some cases, you may receive immunotherapy, such as pembrolizumab (Keytruda), along with neoadjuvant chemotherapy. Immunotherapy drugs have a different list of side effects.

If you’re prescribed immunotherapy and neoadjuvant chemotherapy, talk with your doctor about potential side effects and what to expect.

Not everyone has a good response to neoadjuvant chemotherapy. You can have a partial response or no response. It’s also possible to have a complete response, which means there’s no longer evidence of cancer.

According to a 2020 research review, when compared with people whose tumors don’t respond to chemotherapy, those who experience a complete response are more likely to have long-term disease-free survival and better overall survival.

A 2023 study of 278 people with breast cancer in Indonesia found that the positive response rate was just over 93%, and the rate of negative response was over 6%.

According to a 2024 review, neoadjuvant chemotherapy has been associated with a higher 5-year survival rate.

However, the timing of chemotherapy is only one factor in breast cancer outlook. Other factors that influence outlook are:

  • type of breast cancer
  • stage at diagnosis
  • tumor grade
  • previous treatment
  • overall health

Your oncologist can provide a more personal assessment based on your unique factors.

Neoadjuvant chemotherapy for breast cancer is typically given before your main treatment, which is usually surgery. In some cases, neoadjuvant chemotherapy can result in less invasive surgery.

Not everyone with breast cancer is a good candidate for neoadjuvant chemotherapy. It may benefit those with a large primary tumor, regional spread, or certain types of cancer, such as inflammatory breast cancer.

Imaging tests and biopsy results can help determine whether neoadjuvant or adjuvant chemotherapy is better for you.