“Adjuvant” cancer treatment refers to any therapy you receive after your initial, primary cancer treatment. “Neoadjuvant therapy” refers to supplemental cancer treatment you receive before your primary treatment. 

Adjuvant therapies, also known as “helper therapies,” are the standard for some types of cancers, including breast, ovarian, colorectal, and lung. The term can apply to multiple types of specific therapies, including chemotherapy, radiation, hormone therapy, and immunotherapy.

The main goal of adjuvant cancer treatments is to reduce the risk of cancer recurrence. Receiving adjuvant therapy doesn’t guarantee that your cancer will never return, but you may be able to reduce your risk.

Oncologists are medical doctors who specialize in diagnosing and treating cancer. They use multiple different types of therapy as adjuvant treatments. Depending on the context, you might use one or more adjuvant treatments as part of your treatment plan following the initial intervention.

Adjuvant therapy typically follows an initial surgery, the primary (non-adjuvant) treatment. If surgery isn’t an option, the initial treatment might be radiation or another treatment considered adjuvant in other contexts.

The most promising adjuvant therapy depends on many factors, such as the organ affected by cancer (e.g., breast), how much the cancer has spread, additional cancer characteristics (e.g., presence of certain cancer mutations), overall health, and personal preferences. 

Chemotherapy

Chemotherapy is one of the most common forms of adjuvant therapy. You receive multiple doses of a drug that slows or stops the growth of cancer cells, often through an intravenous (IV) line given through your veins. 

After an initial surgery, you might receive one or more specific chemotherapy drugs over several months. 

For example, if you have stage 2 or stage 3 colorectal cancer (colon or rectal cancer) and specific factors that make your cancer high-risk, your healthcare provider might recommend a chemotherapy drug like Adrucil (fluorouracil) after you’ve had surgery.

Radiation Therapy

Radiation therapy uses high-energy electromagnetic waves to treat cancer. It’s applied specifically to areas where cancer cells might still be present. It kills or slows the growth of cancer cells by damaging their DNA.

Radiation can be given over several weeks after an initial surgery. For example, it’s sometimes given after you’ve had breast-conserving surgery for breast cancer to reduce recurrence risk.

Chemotherapy and radiation therapy might both be used as adjuvant therapies. This is known as chemoradiation. 

Hormone Therapy

Hormone therapy, also called endocrine therapy, is an adjuvant therapy that only works in cancers that respond to hormones. You might receive this kind of adjuvant therapy for several years after initial treatment.

For example, with some types of breast cancer, the hormone estrogen causes cancer cells with estrogen receptors (ER+) to grow more. Nolvadex (tamoxifen) is one example of a hormone therapy that can block these receptors and slow the growth of any remaining cancer. Oral therapy (taking medications by mouth) is often used in early-stage ER+ breast cancer.

Biologics: Molecularly Targeted Therapies and Immunotherapies

A variety of biologic therapies are available as adjuvant cancer therapy. Biologics are medications produced using living cells or organisms.

Adjuvant molecularly targeted therapies are biologics that can help treat some cancers with acquired specific mutations.

For example, some people with breast cancer develop a mutation that causes the cancer to make extra amounts of a protein called “HER2,” which promotes cancer growth. Herceptin (trastuzumab) is a molecularly targeted IV therapy that helps block cancer growth from HER2. You might take it for a year or so, often after receiving other adjuvant treatments like chemotherapy.

Immunotherapies are biologics that help prepare the immune system to fight cancer. For example, Keytruda (pembrolizumab) is an IV immunotherapy that binds and activates T cells (part of the immune system) to find and kill cancer cells.

Keytruda is approved as an adjuvant treatment for some people with stage 2 or stage 3 non-small cell lung cancer. Infusions are given every few weeks for months or up to several years. In this context, it is usually used after surgery in addition to chemotherapy treatment.

Adjuvant therapy is recommended for many different cancers when the benefits of such therapy seem to outweigh the risks. It is most commonly used for breast cancer, lung cancer, or colorectal cancer. However, it is sometimes used for other types of cancer, like prostate cancer. 

Specific characteristics of the cancer can help determine whether or not to use adjuvant therapy. For example, oncologists don’t usually recommend adjuvant chemotherapy for most people with stage 2 colorectal cancer unless their cancer qualifies as high risk (cancer extends through all layers of the colon wall).

In some cases, medical professionals strongly recommend adjuvant therapy. However, the medical consensus can be unclear due to gaps in the scientific literature. Other factors, like a person’s age, their other medical conditions and overall health, the cancer’s potential aggressiveness, and personal preferences, can help make the decision.

FDA Approval

Every year, the U.S. Food and Drug Administration (FDA) approves adjuvant therapies for new contexts—specific treatments for specific cancer types at specific stages). As a result, general recommendations change quickly.

A healthcare provider might also recommend an off-label adjuvant therapy, e.g., a chemotherapy drug that has been used in a slightly different setting. Off-label drugs are used to treat conditions other than those that the drug has been FDA-approved to treat. 

You might also be able to receive an adjuvant treatment as part of a clinical trial, even if it is not currently the standard treatment for your particular diagnosis and situation.

The primary purpose of adjuvant therapies is to help reduce the risk that your cancer will return. Even if you’re in remission—meaning your cancer appears to have been completely removed—cancer cells too small to see can remain in the body. If that happens, these cells may reproduce, and your cancer might return.

The goal of adjuvant cancer therapy is to destroy any of these remaining cells, working as an extra preventative measure to reduce the risk of recurrence.

Adjuvant therapy is not focused on relieving symptoms, at least not in the short term. This contrasts with palliative treatments, which might be given to someone with advanced disease, even if the cancer can’t be cured, to help reduce symptoms.

Certain therapy classes (e.g., chemotherapy) might be discussed as adjuvant or palliative, depending on when they are given and the specific intention.

Adjuvant therapies for cancer come with many different potential side effects. These differ based on the type of adjuvant therapy you receive as well as factors like the cancer stage, so ask your healthcare provider what to expect based on your situation. 

Side effects and potential risks vary based on the overall category (e.g., chemotherapy vs. immunotherapy) and the specific treatment in that class (e.g., type of chemotherapy drug). 

Chemotherapy

Potential side effects of chemotherapy include:

• Fatigue
• Hair loss
• Nausea and vomiting
• Mouth sores
• Nerve pain

Other symptoms, such as poor concentration, mood changes, shortness of breath, increased bruising and risk of infection, bladder and kidney problems, osteoporosis (bone thinning and weakening), and heart-related complications, can also occur.

Most symptoms are the most severe the day after you have your treatment, but others may be delayed or more long-lasting.

Radiation

Radiation can also cause symptoms like fatigue, hair loss, skin changes, and nausea. Depending on the specific site of radiation, additional symptoms might include:

• Headache
• Dysphagia (difficulty swallowing)
• Edema (swelling)
• Pain from scarred areas of skin and muscle
• Sexual and fertility challenges
• Urinary and bladder conditions

Other Adjuvant Therapy Types

Other adjuvant therapies can cause other risks of side effects. Examples include:

• Nausea, headache, fatigue, joint pain, diarrhea, or fever for targeted therapy (targets specific cancer cells) like Herceptin (trastuzumab)
• Menopause-like symptoms, such as hot flashes, mood changes, vaginal dryness or discharge, or night sweats for a hormone-blocking drug like Nolvadex (tamoxifen)
• Skin rash, joint pain, low thyroid hormones, or increased risk of infection for an immunotherapy drug like Keytruda (pembrolizumab)

Long-Term Side Effects

Many side effects resolve after your adjuvant therapy is complete, but some might not. You might experience side effects months or years later vs. during the treatment, including:

• Fatigue
• Sleep challenges
• Muscle, bone, or joint pain
• Depression symptoms
• Difficulty concentrating
• Peripheral neuropathy (numbness or tingling in hands, arms, feet, legs)
• Hair or nail changes

Managing Side Effects

Your treatment team can help you find ways to manage your specific side effects. Strategies might include the following:

• Prioritize rest and limit unnecessary activities to address fatigue
• Eat smaller meals more frequently, consume foods like milkshakes instead of solid foods, and consider taking an anti-nausea medication
• Wash your hands often and avoid contact with sick people to help prevent infection
• Use compression garments or diuretic medications for edema (swelling)
• Keep your mouth moist and eat soft foods if you have mouth sores
• Try treatments like acupuncture, antidepressants, and vaginal lubricants to address some menopause-like symptoms
• Use pain medications or relaxation techniques for pain

Given adjuvant therapy’s potential side effects, time, and costs, you’ll want to choose thoughtfully. Considerations include prognosis effects, what to expect, and benefits of a recommended approach. 

How It Affects Prognosis

If your oncologist recommends one or more adjuvant therapies as a treatment option, ask specific questions about the potential benefits for your particular situation. Perhaps most importantly, ask for evidence showing how the therapy might affect your prognosis (recovery).

Some adjuvant therapies, even those the FDA has approved, don’t necessarily affect a cancer’s prognosis, even though they may slightly increase the amount of time before a cancer returns.

Other Questions To Ask

Ask questions and research the potential drawbacks of each potential therapy, including:

• Length of treatment
• Side effects
• How to manage potential side effects if they occur
• Costs

Ask how strongly your healthcare provider recommends the therapy and why, and ask if other potential adjuvant therapies are available.

Ultimately, all cancer treatment decisions are personal, and the right choice for you might differ from someone else’s. 

Adjuvant cancer therapy is treatment given after an initial, primary cancer treatment. It is an additional treatment that helps destroy remaining cancer cells in case the primary treatment doesn’t completely remove them.

Adjuvant therapy is recommended for some people with cancer, but it might not be appropriate for everyone. Always weigh the potential risks and benefits of all cancer treatment, including specific adjuvant therapies, with your healthcare provider.