Neoadjuvant chemotherapy is chemotherapy that a person with cancer receives before their primary course of treatment. The aim is to shrink a cancerous tumor using drugs before moving onto other treatments, such as surgery.

Neoadjuvant chemotherapy helps doctors target cancerous growths more easily at a later stage. Oncologists may also use this type of chemotherapy when a tumor is too large for a major operation or is affecting vital organs.

In this article, we look at the uses, benefits, side effects, and risks of neoadjuvant chemotherapy. We also explore the success rates and suggest questions that a person might wish to ask about the treatment.

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Neoadjuvant chemotherapy is a course of cancer treatment that doctors typically use ahead of surgery. According to the American Cancer Society (ACS), this treatment helps shrink cancerous tumors to make them easier to remove. Neoadjuvant chemotherapy may also kill cancerous tissue that is not yet visible on imaging tests.

Doctors often use neoadjuvant chemotherapy as a gauge to see how cancer might respond to a particular medication. If the cancer does not respond to that drug, doctors will use other drugs for treatment. They might decide to try another family of drugs or a combination of two or three different drugs.

Adjuvant chemotherapy occurs after the primary treatment, rather than before. Oncologists may recommend either neoadjuvant or adjuvant chemotherapy depending on various factors, including:

  • cancer type
  • cancer progression
  • treatment goals, such as easing symptoms or slowing growth
  • the likelihood that a person will be able to tolerate multiple treatments

According to a 2015 article, neoadjuvant chemotherapy has no proven benefits other than:

  • making the surgical removal of tumors easier
  • making inoperable tumors operable
  • reducing the need for mastectomies

The authors note that although neoadjuvant chemotherapy has other potential benefits, clinical trials have not conclusively proven them. Also, they state, it does not seem that this treatment directly increases survival rates in comparison with adjuvant therapy.

However, certain types of cancers respond especially well to neoadjuvant chemotherapy, and the treatment is sometimes so effective that it reduces the chance of cancer coming back.

For example, a 2017 study found that neoadjuvant chemotherapy for breast cancer reduced mastectomy rates by 7–13%. It had this effect because early stage breast cancer responds quickly to the treatment, improving the chance that a person will not need surgery to remove breast tissue.

In the past, doctors used neoadjuvant chemotherapy for the treatment of inoperable, locally advanced breast cancer. Today, they use it for many types of cancer, including colon, lung, bladder, and prostate.

Doctors may use several types of drugs for neoadjuvant chemotherapy. The ACS lists the following:

  • anthracyclines, which doctors use to treat various cancers affecting the bladder, breasts, kidneys, ovaries, and other parts of the body
  • taxanes, which target solid tumors in the breast, lungs, and ovaries
  • 5-fluorouracil, which doctors administer by injection to treat cancer of the breast, colon, rectum, pancreas, and stomach
  • cyclophosphamide (Cytoxan), which oncologists primarily use for forms of lymphoma
  • carboplatin (Paraplatin), which doctors use to treat ovarian and lung cancer

Often, doctors will use a combination of two or three drugs at a time.

There are several ways doctors can administer neoadjuvant chemotherapy. A person may receive it:

  • orally
  • intravenously, through an IV line
  • via injection

The method of delivery depends on several factors, including the type and stage of cancer and the drugs an oncologist has prescribed.

Doctors usually administer neoadjuvant chemotherapy in cycles, with a period of rest following each treatment. For breast cancer, chemotherapy typically lasts 3–6 months overall.

However, an oncologist may recommend more or fewer cycles depending on the progression of the cancer and how well the individual responds to the medication.

People can receive neoadjuvant chemotherapy in a doctor’s office, in the hospital, or at home. It can take as little as a few minutes to deliver the treatment or significantly longer, depending on the method.

The main difference between neoadjuvant and adjuvant chemotherapy is the way that doctors use each treatment.

Oncologists typically use neoadjuvant chemotherapy to maximize the chance of the primary treatment, such as surgery, working effectively. They can also use it to test a person’s response to different drugs. Adjuvant chemotherapy kills cancerous cells that may remain after the primary treatment.

Aside from this, both forms of treatment are similar in terms of their administration. Both types:

  • reduce the risk of cancer coming back
  • usually involve a treatment course of 3–6 months
  • are adjustable according to a person’s unique circumstances and tolerance

The survival rate after both treatments depends on the type and progression of a person’s cancer, as well as the drugs an oncologist chooses and the person’s overall health.

Some of the possible side effects of chemotherapy include:

There are drugs that doctors can prescribe to control certain side effects, such as vomiting. Usually, the side effects go away once chemotherapy is complete.

In some cases, though, chemotherapy can cause more long-term effects. For those undergoing chemotherapy for breast cancer, these could include:

  • hand-foot syndrome
  • nerve damage
  • heart damage
  • decreased mental functioning
  • less energy
  • for some drugs, an increased risk of leukemia

Chemotherapy can also cause early menopause or problems with fertility. These issues are more likely to occur with certain classes of chemotherapy agents, such as the alkylating agents cyclophosphamide and procarbazine, which can harm the ovaries.

The risk of infertility is higher the older someone is when they begin chemotherapy. However, there are options for preserving fertility before treatment, such as embryo or egg freezing. Alternatively, a person can consider sourcing an egg donor after treatment. People who wish to conceive after they finish chemotherapy can discuss their options with a doctor before starting treatment.

Even if a person does not plan to get pregnant after their treatment, infertility and the other long-term effects of cancer treatment may cause feelings of stress, sadness, anger, or grief. It is important to seek support for the possible mental health effects of cancer and chemotherapy.

Learn more about coping with a cancer diagnosis.

The ACS recommends asking about the following before starting treatment:

  • Which drugs would you recommend for my treatment?
  • How will you administer treatment?
  • How frequent will treatments be?
  • How long will the treatments last?
  • What are the possible side effects of the drugs?
  • Will I need to make any lifestyle changes (e.g., to exercise, diet, sex, or work)?

It may also be advisable to ask whether the treatment will require prior authorization from a health insurance provider and who would be responsible for obtaining this.

These are only a few of the questions that a person may have before undergoing neoadjuvant chemotherapy. They may find it helpful to take notes during appointments or to have a friend or family member attend alongside them. If a person feels confused about anything, their oncologist should be able to answer their questions and provide more clarity.

Doctors use neoadjuvant chemotherapy before a person’s primary cancer treatment. It can shrink tumors, making surgery possible in otherwise inoperable areas. It can also allow doctors to test a chemotherapy drug to gauge how the body responds to it.

The effectiveness of neoadjuvant chemotherapy depends on many factors, including the type and stage of cancer a person has, as well as their individual response to different drugs. If a person has any questions about their treatment plan, they should speak with their medical team.

Learn more about cancer research, treatments, and more at Medical News Today‘s cancer hub.