What are the side effects of immunotherapy for Breast Cancer

Side Effects of Immunotherapy for Breast Cancer

Immunotherapy works differently than traditional chemotherapy, which means the side effects can be quite different too. Let me explain what you might experience and how they're managed.

How Immunotherapy Side Effects Differ

According to the NCCN Guidelines for Management of Immunotherapy-Related Toxicities, immunotherapy uses your immune system to fight cancer cells. However, this can sometimes cause your immune system to attack healthy cells in your body—creating what doctors call "immune-related adverse events" (irAEs). These are distinct from the side effects of traditional chemotherapy.

Common Immunotherapy Side Effects

Skin and Allergy Reactions:

• Rashes and skin inflammation
• Hives and welts
• Hypersensitivity reactions (exaggerated immune responses to the drug)

Gastrointestinal Issues:

• Diarrhea (frequent, watery bowel movements)
• Nausea and loss of appetite
• Inflammation of the digestive tract

Systemic (Whole-Body) Effects:

• Fatigue (extreme tiredness and lack of energy)
• Fever and flu-like symptoms
• Muscle aches

Serious but Less Common:

• Pneumonitis (lung inflammation) - can cause trouble breathing
• Myocarditis (heart inflammation)
• Cytokine release syndrome (CRS) - a condition where immune cells release large amounts of signaling molecules, causing fever, muscle aches, nausea, headache, rash, fast heartbeat, low blood pressure, and trouble breathing

Endocrine (Hormone) System Effects

One important difference with immunotherapy is that it can affect your hormone-producing glands:

• Thyroid dysfunction (hypothyroidism)
• Adrenal insufficiency (when your adrenal glands don't produce enough hormones)
• New-onset Type 1 diabetes
• Pituitary gland problems

According to the NCCN Guidelines, healthcare providers should screen for and manage these endocrine dysfunctions in patients treated with immune checkpoint inhibitors.

Blood-Related Side Effects

• Blood clots - cancer and its treatment can cause clots that block blood flow and oxygen in the body. These clots can travel and cause stroke or breathing problems
• Low white blood cell counts, which can increase infection risk

Managing Side Effects

The good news is that most immunotherapy side effects can be managed:

• Diarrhea: Staying well-hydrated is important; your care team will provide specific management strategies
• Fatigue: A balanced diet, exercise, yoga, acupuncture, and massage therapy can help. You may be referred to a nutritionist
• Skin reactions: Moisturizers and protective measures help
• Serious reactions: Your doctor may need to pause or stop immunotherapy temporarily or permanently, depending on severity

Important Monitoring

According to NCCN Guidelines, patients receiving immunotherapy should have:

• Regular screening for immune-related side effects
• Monitoring for endocrine dysfunction (thyroid, adrenal, and blood sugar issues)
• Cardiac monitoring if you're also receiving certain other treatments

Questions to Ask Your Oncology Team

1. Which specific immunotherapy drug(s) will I receive, and what are the most common side effects I should watch for?

2. How will you monitor me for endocrine problems like thyroid issues or diabetes during treatment?

3. What symptoms should I report immediately versus those I can manage at home?

4. If I develop a serious side effect, what's the plan—will we pause treatment, switch drugs, or add supportive medications?

5. Are there any supplements, foods, or activities I should avoid while on immunotherapy? (For example, according to integrative oncology guidelines, patients on immunotherapy should avoid medicinal mushrooms and alcohol)

6. How long do these side effects typically last after treatment ends?

Key Takeaway

While immunotherapy side effects can be serious, they're often manageable with proper monitoring and support. The difference from chemotherapy is that immunotherapy side effects tend to be immune-related rather than from direct cell toxicity. Your care team should actively monitor you and adjust your treatment plan if needed to keep you safe while fighting your cancer.

---

This information is for educational purposes only. Always consult your healthcare team for personalized medical advice and decisions.