What Is Adjuvant Therapy?

Why Doctors Recommend Multiple Treatments for Cancer

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When you’re getting cancer treatment, you may be given a combination of surgery and other medications, treatments, or drugs. These additional treatments are sometimes referred to as adjuvant therapies, adjunct therapies, or by other names.

Many different treatments may be administered as adjuvants. They may include adjuvant chemotherapy, radiation, immunotherapy, or targeted therapies. Adjuvant therapies are a common part of treatment plans for breast cancer, colon cancer, and lung cancer.

The primary therapy (such as surgery) treats the main tumor locally, while the adjuvant serves as a backup to kill any cancer the primary therapy may have missed. The adjuvant treatment can even come before the primary therapy, in which case it’s called neoadjuvant therapy.

This article will review adjuvant, neoadjuvant, maintenance, and adjunct therapies, along with what types of treatments are used for these therapies, what side effects to expect, and some frequently asked questions.

Adjuvant Therapy Cancer Treatments

Verywell / Laura Porter

Types of Adjuvant Therapy

Even after the successful removal of a cancerous tumor, cancer cells can remain either at that site or in other areas of the body where they’ve spread. Adjuvant therapy is any additional therapy you may undergo to reduce the risk of cancer returning after successful surgery or initial treatment. 

The idea of adjuvant therapy is that treatments (like chemotherapy) applied to the entire body will be able to find and kill cancer cells that the original treatment may have missed. These individual cancer cells, sometimes called micrometastases, can give rise to new tumors.

Additional body-wide treatments may help prevent the cancer cells from growing and keep the tumor from coming back. These therapies are becoming more popular as new cancer treatments are developed with fewer side effects.

Your doctor may suggest these therapies at any time during your cancer treatment. They may already be included in your initial treatment plan or be added depending on how your cancer reacts to initial treatment attempts.

What Is Adjuvant Therapy?

The classic definition of adjuvant therapy is a treatment used after an initial primary therapy—either radiation or surgery—to help prevent cancer from returning.

Different terms you might hear related to adjuvant therapies include the following.

Combination Therapy

Combination therapy or multimodality treatment means that more than one approach is being used to treat your cancer. It is a general term to describe therapies that combine multiple treatment approaches.

Neoadjuvant Therapy

Neoadjuvant therapy, sometimes called induction therapy, is given before surgery or another primary treatment like radiation. These treatments may help reduce tumor size, make surgery easier, or even kill cancer cells that have already spread.

Adjunct Therapy

Adjunct therapy, or adjunctive therapy, is another approach to combination treatment. Adjunct therapies are used alongside the primary treatment method to make it work better.

Post-Remission Therapy

Therapy given after a patient goes into remission from cancer is called post-remission therapy. These treatments are used to kill any remaining cancer in the body. They’re sometimes called consolidation therapy or intensification therapy.

Maintenance Therapy

Maintenance therapy is another name for adjuvant therapies given after the original treatment to help reduce the risk that cancer will come back. However, maintenance therapy is a term more often used when doctors talk about the long-term use of treatments. The use of maintenance therapy can span 10 years or more.

Maintenance therapies aim to keep the patient in full remission (no signs of cancer and no symptoms) or to promote partial remission, which shrinks the tumors and lengthens lifespan.

Adjuvant Therapy Treatments

Many different treatments are used as adjuvant therapies. Depending on the type of cancer, these may be used as primary therapies. 

The efficacy of adjuvant therapy depends on your cancer, your stage, your general health and wellness, the types of therapies used, and the goals of the treatments. It does not work for all types of cancer, so make sure to talk to your doctor about the right approaches for your specific case.

Adjuvant Chemotherapy 

The most often used adjuvant therapy is chemotherapy delivered before or after surgery to shrink a tumor or kill remaining cancer cells. Adjuvant chemotherapy is usually given using just one drug (not a combination) and in lower doses to minimize side effects.


Immunotherapies are drugs that specifically prime the body’s own immune system to fight cancer. The immune system already finds and kills many of the cells that go rogue on their way to becoming cancerous, but as some cancers develop, they learn how to escape the immune system. 

Immunotherapies essentially work to unblind the body’s natural immune reaction, sending the body’s white blood cells on a quest to find and kill any cancer cells remaining after surgery or radiation.

Hormone Therapy

Hormone therapy, also called endocrine therapy, includes drugs that slow growth in specific types of cancers. These cancers typically rely on our body’s natural hormones to grow, so disrupting that pathway can slow the growth of these cancers, including prostate and breast cancer.

Studies have shown that extended hormone therapy with an aromatase inhibitor is a good choice for breast cancer types with hormone receptors.

These therapies can be used for 10 years, with lasting benefits for disease-free survival in people who have gone through menopause and have been diagnosed with early-stage hormone receptor-positive breast cancer. 

Patients undergoing extended adjuvant hormone therapy for breast cancer were more likely to be disease-free at five years and less likely to develop cancer in the other breast.


Radiation therapy uses high-energy waves to kill cancer cells by breaking apart their DNA. Unfortunately, this destructive action is nonspecific, so it can also damage normal cells.

It’s typically used locally in a spot in your body that your doctor knows contains cancer cells. It’s sometimes used as a primary treatment, but it may also be used as an adjuvant or neoadjuvant treatment, depending on your cancer and the goals of radiation in the treatment plan.

Targeted Therapy

Targeted therapies are drugs that specifically attack your cancer based on its characteristics. For example, some cancers make proteins on the outside of their cells that these drugs can find and label and sometimes kill the cancer cells remaining in your body.

Because they specifically target cancer cells, these types of therapies may have fewer side effects. However, the use of targeted therapies is very dependent on not just the cancer type, but also on your specific cancer’s genetic characteristics—the changes that made the cancer cells grow out of control.

Adjuvant Therapy Side Effects

Just like primary treatments, adjuvant cancer therapies come with side effects. The side effects of adjuvant therapy will vary based on the types of treatment and the doses being used. 

Doctors usually aim to keep the side effects of adjuvant therapies low, especially for maintenance therapies that may be used for years. 

When used as an adjuvant, chemotherapy is usually given at lower doses and as a single drug to minimize side effects. Typical side effects of chemotherapy include:

  • Fatigue
  • Pain
  • Mouth sores
  • Digestive distress, including nausea, vomiting, diarrhea, and constipation 

Side effects of immunotherapy treatments vary by the type of drug and how it is given. If the drug is injected or infused, there may be reactions at the site of administration. General flu-like symptoms are common, as well as digestive issues and an increased risk of infection.

The side effects of hormone therapy depend on the type of hormone being disrupted. For breast cancer adjuvant therapy with aromatase inhibitors, side effects may include bone loss, osteoporosis, and fractures.

Radiation can cause mild side effects, including fatigue and skin changes, as well as other side effects based on where the radiation is given.

Targeted therapy side effects depend on the drugs being used and their dosages. Common side effects of targeted therapies include digestive issues and liver problems.


Adjuvant therapy for cancer is a treatment done in addition to the treatment given to the primary tumor (such as surgery). It aims to kill any cancer cells remaining at the site or that have spread to other places in the body. Adjuvant therapy may be chemotherapy, immunotherapy, hormone therapy, targeted therapy, or radiation therapy.

A Word From Verywell

A cancer diagnosis is hard enough on its own, but there are additional challenges when faced with a whole new vocabulary and multiple treatment options. Adjuvant therapies can cause side effects, cost you more, and require additional visits to the doctor or clinic. But they can also reduce the risk of cancer returning or prolong your life. 

The benefits and effectiveness of adjuvant therapy depend highly on what type of cancer you have and how advanced it is. Likewise, the risks and costs depend on the types of treatment being considered.

As always, make sure to talk to your cancer doctor or oncologist to understand if adjuvant therapies are the right treatment for your cancer. Ask them any questions about your treatments if you’re worried about any part of the process.

Frequently Asked Questions 

What is the goal of adjunct therapy?

Adjunct therapies are used alongside the primary treatment method to make the primary treatment (such as surgery or radiation) work better.

Are neoadjuvant and adjuvant therapies used together?

Because they are administered at different phases of the treatment process, your doctor may suggest you get both neoadjuvant therapies and adjuvant therapies. Neoadjuvant therapies happen before the primary treatment, while adjuvant or maintenance therapies are used after addressing the original tumor with surgery or radiation.

Who shouldn’t do adjuvant chemotherapy?

Adjuvant therapies are not recommended for every cancer patient. Some types of cancer do not have good evidence supporting the use of neoadjuvant, adjuvant, or maintenance chemotherapies. Your cancer stage and the likelihood of remission are also important. If you’re not at high risk for cancer to come back, you may not be a good candidate for adjuvant therapies.

15 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  3. American Society of Clinical Oncology. Understanding maintenance therapy.

  4. National Cancer Institute. Dictionary of cancer terms: neoadjuvant therapy.

  5. National Cancer Institute. Dictionary of cancer terms: adjunct therapy.

  6. National Cancer Institute. Dictionary of cancer terms: postremission therapy.

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  8. National Cancer Institute. Hormone therapy to treat cancer.

  9. National Cancer Institute. Extended adjuvant therapy beneficial for some women with breast cancer.

  10. National Cancer Institute. Radiation therapy to treat cancer.

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  13. American Society of Clinical Oncology. Side effects of immunotherapy.

  14. American Society of Clinical Oncology. Side effects of radiation therapy.

  15. National Cancer Institute. Targeted therapy to treat cancer.

By Jennifer Welsh
Jennifer Welsh is a Connecticut-based science writer and editor with over ten years of experience under her belt. She’s previously worked and written for WIRED Science, The Scientist, Discover Magazine, LiveScience, and Business Insider.