The Who, What, Where, When and Sometimes, Why.

Neoadjuvant Therapies

What is neoadjuvant therapy?

In some cases, treatment with chemotherapy, HER2-targeted therapy or hormone therapy may be given before breast surgery. When treatment is given before surgery, it’s called neoadjuvant therapy or preoperative therapy.

Neoadjuvant therapy drugs are often the same as those used after surgery (called adjuvant therapy). 

What to expect before neoadjuvant therapy

Before neoadjuvant therapy begins, you will have a needle biopsy to remove a small amount of tumor tissue.

A clip is often placed in the tumor bed so the tumor can be found later when you have surgery. This clip is radio-opaque, so it can be seen on an X-ray. It’s usually removed during the surgery.

Tests on the biopsy tissue confirm your diagnosis and identify tumor characteristics, such as hormone receptor status and HER2 status. These factors determine the neoadjuvant therapy that will offer the most benefit. 

Neoadjuvant chemotherapy

If your treatment plan includes chemotherapy, neoadjuvant chemotherapy may be an option as a first treatment.

Chemotherapy has the same effectiveness whether it’s given before surgery or after surgery. The timing of chemotherapy around surgery does not affect survival (learn more).

However, for some women, neoadjuvant chemotherapy may change their surgical options. Neoadjuvant chemotherapy may be able to shrink a larger tumor enough so lumpectomy plus radiation therapy becomes an option instead of mastectomy [7].

Neoadjuvant chemotherapy may also be given to women who have enlarged lymph nodes in the underarm area due to the spread of breast cancer to these lymph nodes. Neoadjuvant therapy can shrink the lymph nodes. This makes the surgery to remove the nodes easier.

Most tumors respond to neoadjuvant chemotherapy.

If a tumor doesn’t respond to one chemotherapy drug regimen, a different combination of drugs may be used or it may be best to proceed with surgery.

Types of neoadjuvant chemotherapy regimens

Neoadjuvant chemotherapy regimens are the same as the standard regimens used after surgery. Most are anthracycline- or taxane-based therapies.

For HER2-positive tumors, neoadjuvant therapy usually includes a combination of chemotherapy and the HER2-targeted therapy drugs trastuzumab (Herceptin) and pertuzumab (Perjeta).

Learn more about neoadjuvant trastuzumab and pertuzumab.

Learn more about chemotherapy drugs.

Learn more about HER2 status

Recurrence and survival with neoadjuvant chemotherapy

A meta-analysis that combined the results of 12 studies found no difference in rates of breast cancer recurrence or overall survival in women who had neoadjuvant chemotherapy versus those who had adjuvant chemotherapy [146].

One large study found at 10 years after treatment with neoadjuvant therapy, rates of breast cancer recurrence were [147]:

  • About 10 percent for women who were able to have lumpectomy plus radiation therapy instead of mastectomy
  • About 13 percent for women who had mastectomy, with no radiation therapy 

Learn more about lumpectomy versus mastectomy and survival.           


For a summary of research studies on neoadjuvant chemotherapy, visit the Breast Cancer Research Studies section.

Neoadjuvant hormone therapy

Neoadjuvant hormone therapy (usually with an aromatase inhibitor) may change a woman’s surgical options. It may be able to shrink a large tumor enough so lumpectomy plus radiation therapy becomes an option instead of mastectomy [7].

Neoadjuvant hormone therapy is only used to treat hormone receptor-positive (ER-positive and/or PR-positive) breast cancers.

It’s an option for some postmenopausal women, including those who can’t have chemotherapy due to health problems or advanced age, and for some women who have a very low risk of breast cancer recurrence [7].

Survival is the same whether you start taking hormone therapy before surgery or after surgery.


For a summary of research studies on neoadjuvant hormone therapy, visit the Breast Cancer Research Studies section.

Learn more about hormone receptor status.

Neoadjuvant therapy for HER2-positive breast cancers

For HER2-positive breast cancers, neoadjuvant therapy usually includes a combination of the HER2-targeted therapy drugs trastuzumab (Herceptin) and pertuzumab (Perjeta).


Trastuzumab is given by vein (through an IV) or by injection every 3 weeks for one year.

Since trastuzumab is given over a long period of time, if you have neoadjuvant trastuzumab, you won’t get all the trastuzumab before surgery. You’ll likely get some trastuzumab before surgery and some after surgery.

Trastuzumab is not usually given at the same time as anthracycline-based chemotherapy.


Pertuzumab may be used in combination with trastuzumab for neoadjuvant therapy and/or adjuvant therapy. 

Under study

Other HER2-targeted therapy drugs, including ado-trastuzumab emtansine (Kadcyla, T-DM1, trastuzumab emtansine), are under study for neoadjuvant therapy for HER2-positive breast cancers [140].

Learn about HER2 status and prognosis.  

Pathologic response

After neoadjuvant therapy, a pathologist will check the breast tissue removed during surgery for a pathologic response.

Pathologic response describes how much of the tumor is left in the breast and lymph nodes after neoadjuvant therapy.

Pathologic complete response

In some cases, neoadjuvant therapy will shrink the tumor so much the pathologist can’t find any remaining cancer. This is called a pathologic complete response (pCR).

A pCR can give some information about prognosis, but it doesn’t usually change your treatment plan.

Although a pCR is encouraging, it doesn’t mean the cancer will never return. And, many people who don’t have a pCR will still do very well.

pCR rates after neoadjuvant chemotherapy are highest among women with tumors that are [149]:

  • High-grade
  • Hormone receptor-negative (estrogen receptor-negative and/or progesterone receptor-negative)
  • HER2-positive, when the neoadjuvant treatment plan includes trastuzumab and pertuzumab

However, neoadjuvant chemotherapy can be effective in treating tumors of any grade and hormone receptor status.

Learn more about tumor grade.

Learn more about hormone receptor status and HER2 status.

After neoadjuvant therapy ends

To check the response to neoadjuvant therapy, you may have several tests, including a clinical breast exam, a mammogram, a breast MRI and/or a breast ultrasound

Surgery is then planned much in the same way as if you didn’t have neoadjuvant therapy.

Sentinel node biopsy and neoadjuvant therapy

A sentinel node biopsy checks for cancer in the lymph nodes in the underarm area (axillary lymph nodes).

Sentinel node biopsy is usually done after neoadjuvant therapy, at the time of your breast surgery.

However, it may be done before neoadjuvant therapy begins if the status of the lymph nodes will affect your surgery options or your adjuvant (after surgery) drug therapy options [7].

Treatment guidelines

Although the exact treatment for breast cancer varies from person to person, guidelines help ensure high-quality care. These guidelines are based on the latest research and agreement among experts.

The National Comprehensive Cancer Network (NCCN) and the American Society of Clinical Oncology (ASCO) are respected organizations that regularly review and update their guidelines.

In addition, the National Cancer Institute (NCI) has treatment overviews.

Talk with your health care team about which treatment guidelines they use.

Updated 05/24/21


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