If you are undergoing targeted therapies for desmoid tumors, such as nirogacestat (Ogsiveo) — the only FDA-approved treatment option for desmoid tumors — or tyrosine kinase inhibitors (TKIs), you may wonder whether supplements could interact with these treatment options. Unlike chemotherapy, which attacks rapidly dividing cells, targeted therapies work by interfering with specific molecules that drive tumor growth. While these treatments are highly effective for desmoid tumors, they can also be sensitive to outside influences, including supplements.

Desmoid tumors, also known as aggressive fibromatosis, are noncancerous but locally aggressive tumors that form in connective tissues. While they don’t spread to other parts of the body, desmoid tumors can cause significant complications if they grow, impacting nearby organs, muscles, and other tissues. In addition to targeted therapies and chemotherapy, treatments for desmoid tumors may also include surgery or radiation therapy.

It’s important to support your body as best you can during treatment, and using supplements might seem like a good way to do that. However, before adding any vitamins, herbs, or other supplements to your regimen, it’s important to understand how they might interact with your treatment.

The Role of Supplements in Targeted Therapy and Chemotherapy

Supplements are often seen as a way to boost health by providing nutrients that may be lacking in your diet. For people with conditions like cancer or tumors, the main goals of taking supplements can vary. Some may take them to improve immune function, reduce side effects from medications, or help with recovery after surgery or radiation. However, when it comes to desmoid tumors, the use of supplements must be approached with caution.

The American Cancer Society emphasizes that while dietary supplements can have some benefits, they may also interfere with conventional cancer treatments. This is especially true for treatments that rely on specific chemical reactions or medications that target tumor cells.

Let’s take a look at some common supplements and their potential effects on desmoid tumor treatment.

Antioxidants (Vitamin C, Vitamin E)

Antioxidants are popular supplements because of their ability to neutralize free radicals — unstable molecules that can cause cell damage. Some studies suggest that antioxidants can protect normal cells from the damage caused by treatments like radiation or chemotherapy. However, antioxidants might also protect tumor cells, reducing the effectiveness of these treatments.

Taking large doses of antioxidants could make certain treatments, including chemotherapy and radiation, less effective. This is because therapies like radiation generate free radicals to kill tumor cells, and antioxidants may interfere with this process. Because oncologists are still debating this topic and more study is needed, it’s best to discuss any plans to take antioxidants with your health care team.

Herbal Supplements

Herbs like turmeric (curcumin) and green tea extract are often promoted for their anti-inflammatory and anticancer properties. Curcumin, for example, has shown promise in laboratory studies for its potential to stop tumor growth. However, these effects have not been consistently demonstrated in human clinical trials.

Additionally, herbal supplements can interfere with prescribed medications. Some herbs may affect how your body processes drugs used in desmoid tumor treatment, leading to reduced effectiveness or increased side effects. Always check with your oncologist before using herbal supplements, as some may interact with your treatment.

Vitamin D

Vitamin D is essential for bone health and immune function, and many people are deficient in it. Some research suggests that having enough vitamin D may lower the risk of certain cancers, although the evidence is not strong enough to recommend it for everyone.

For people with desmoid tumors, keeping enough vitamin D may support overall health, especially if treatment makes it hard to spend time outdoors. However, avoid taking very high doses unless your health care provider prescribes them.

Omega-3 Fatty Acids

Omega-3 fatty acids, found in fish oil supplements, have anti-inflammatory properties. Because inflammation is a key factor in many types of tumor growth, including desmoid tumors, reducing inflammation could be beneficial.

That said, omega-3 supplements could increase the risk of bleeding, particularly for people having surgery, although this is still debated. If you are scheduled for surgery or taking blood-thinning medications, speak to your doctor before taking omega-3 supplements.

Possible Risks of Supplements During Treatment

Taking supplements during desmoid tumor treatment comes with some risks. Some potential concerns include:

Interference With Medications

Many supplements, especially herbs, can change how your body processes targeted therapies or chemotherapy. For example, St. John’s Wort, often used for depression, can make some cancer medications less effective.

Overloading the Liver and Kidneys

Your liver and kidneys are responsible for filtering toxins, including those from medications and supplements. Taking high doses of certain supplements can put extra stress on these organs, leading to problems.

Unknown Long-Term Effects

While some supplements may seem beneficial, there is a lack of long-term studies on their effects in people undergoing cancer treatments. What seems helpful in the short term might have unpredictable consequences.

Supplements That May Be Safe During Treatment

While many supplements can interfere with treatment, a few might be safe or even helpful. Always check with your health care team before starting any supplement.

Probiotics

Keeping your gut healthy is important, especially during treatments that can upset digestion or weaken the immune system. Probiotics can help balance your gut microbiome, improving digestion and potentially supporting the immune system.

However, if your immune system is weakened (like during chemotherapy), talk to your doctor before using probiotics. Some probiotics could increase the risk of infection in people with weakened immune systems.

Magnesium

Magnesium is essential for muscle function and bone health. Some types of chemotherapy can lower your magnesium levels, leading to headaches or muscle cramps. If your magnesium is low, supplementation might help, but you should take it with your doctor’s guidance.

B Vitamins

B vitamins, especially B12 and folic acid, are important for keeping your energy up and supporting your nervous system. They may help manage fatigue, which is a common side effect of cancer treatments. As with other supplements, it’s best to check with your doctor before starting vitamin B supplements to make sure they won’t interfere with your treatment.

The Role of Diet in Supporting Desmoid Tumor Treatment

In addition to carefully considering supplements, you should also think about your overall diet. What you eat plays a crucial role in supporting your treatment for desmoid tumors. Focus on whole foods like vegetables, fruits, lean proteins, and whole grains. These foods provide essential nutrients without the risks of high-dose supplements. Fruits and vegetables have natural compounds called phytonutrients, which can help with digestion and energy levels.

It's also a good idea to limit processed foods, refined sugars, and alcohol, which can increase inflammation and stress your body during treatment. A nutrient-dense diet, rich in natural foods, can better support immune function and overall recovery. If you’re unsure how to improve your diet during treatment, think about consulting with a registered dietitian who specializes in cancer care for personalized advice.

Talk With Others Who Understand

MyDesmoidTumorTeam is the social network for people with desmoid tumors and their loved ones. On MyDesmoidTumorTeam, more than 400 members come together to ask questions, give advice, and share their stories with others who understand life with desmoid tumors.

Are you living with desmoid tumors and thinking about taking a supplement? Have you had open discussions about supplements with your oncology team? Share your experience in the comments below, or start a conversation by posting on your Activities page.