Cancer immunotherapy has fundamentally changed what is possible in oncology. Where chemotherapy attacks both cancerous and healthy cells indiscriminately, immunotherapy works differently — it activates, enhances, or redirects the body's own immune system to recognise and destroy cancer cells. The results have been remarkable, offering long-term remission in cancers that were once considered untreatable.
But this power comes with a particular set of challenges. When the immune system is amplified, it does not always limit its attack to cancer cells. It can turn on healthy organs and tissues — a phenomenon known as immune-related adverse events (irAEs). Understanding these side effects, recognising them early, and managing them properly is essential for anyone undergoing immunotherapy.
How Immunotherapy Works — And Why Side Effects Happen
Most modern immunotherapy drugs are checkpoint inhibitors — medications that block proteins like PD-1, PD-L1, or CTLA-4 that cancer cells use to "hide" from immune detection. By releasing these brakes on the immune system, checkpoint inhibitors allow T-cells to attack tumours more aggressively.
The problem is that these same brakes also prevent the immune system from attacking the body's own healthy tissue. When those brakes are removed, the immune system can become overactive and begin targeting normal organs — the skin, lungs, liver, intestines, endocrine glands, and more.
This is fundamentally different from chemotherapy side effects, which are caused by toxicity. Immune-related side effects are caused by inflammation, and they require a completely different approach to management.
Common Immune-Related Side Effects
Skin Reactions
Skin is the most commonly affected organ, occurring in up to 50% of patients on checkpoint inhibitors. Symptoms include rash, redness, itching, and in rare but serious cases, blistering conditions like Stevens-Johnson syndrome.
Management: Mild rashes are treated with topical corticosteroids and antihistamines. Severe or widespread rashes may require systemic steroids and temporary suspension of immunotherapy.
Colitis — Gut Inflammation
Immune-related colitis presents as persistent diarrhoea, abdominal cramping, and in severe cases, blood in the stool. It is more common with CTLA-4 inhibitors like ipilimumab. Left unmanaged, it can progress to bowel perforation — a medical emergency.
Management: Mild cases are managed with hydration and dietary adjustments. Moderate to severe colitis requires high-dose corticosteroids and, in refractory cases, infliximab or vedolizumab — biologics that suppress specific immune pathways.
Patients receiving the best immunotherapy treatment in Mysore are carefully monitored for early gastrointestinal symptoms so that colitis can be addressed before it escalates.
Pneumonitis — Lung Inflammation
Immune-related pneumonitis is less common but potentially life-threatening. It presents as a new or worsening cough, shortness of breath, chest discomfort, or reduced exercise tolerance. It can be difficult to distinguish between infection and tumour progression on imaging alone.
Management: Mild pneumonitis may require only a temporary hold on therapy and close monitoring. Grades 3 and 4 pneumonitis demand immediate high-dose corticosteroids, hospitalisation, and permanent discontinuation of the offending drug.
Residents of JP Nagar, Vijayanagar, and Saraswathipuram in Mysore who are on active immunotherapy should report any new respiratory symptoms promptly to the best medical oncologist in Mysore without waiting for their next scheduled appointment.
Hepatitis — Liver Inflammation
Immune-mediated hepatitis is often asymptomatic in its early stages, discovered only through routine blood tests showing elevated liver enzymes (AST/ALT). In later stages, it may cause fatigue, jaundice, and abdominal pain.
Management: This is why regular liver function monitoring during immunotherapy is non-negotiable. Treatment involves corticosteroids, and severe cases may require mycophenolate mofetil if steroids alone are insufficient.
Endocrine Disorders
The immune system can attack endocrine glands — particularly the thyroid, pituitary, and adrenal glands — disrupting hormone production. Hypothyroidism is the most common endocrine irAE, causing fatigue, weight gain, and cold intolerance. Hypophysitis (pituitary inflammation) can cause severe headaches, vision changes, and hormonal collapse.
Management: Most endocrine side effects are managed with hormone replacement rather than immunosuppression, and many patients require lifelong thyroid or adrenal supplementation.
Less Common but Serious Side Effects
Beyond the organs above, immunotherapy can occasionally trigger inflammation in the heart (myocarditis), kidneys (nephritis), nervous system (neuropathy, encephalitis), eyes (uveitis), and joints (arthritis). Though rare, these conditions can be rapidly life-threatening if missed.
Myocarditis, for instance, has a mortality rate of over 40% if not diagnosed and treated urgently. Any chest pain, palpitations, or sudden breathlessness in a patient on immunotherapy must be investigated immediately.
Patients seeking the best cancer specialist in Mysore benefit from a multidisciplinary team approach — where oncologists, cardiologists, pulmonologists, gastroenterologists, and endocrinologists collaborate to monitor and manage the full spectrum of possible iraes.
The Role of Steroids and Immunosuppression
The cornerstone of managing most immune-related side effects is corticosteroids — typically prednisone or methylprednisolone. These broadly suppress the immune response, driving inflammation. For severe or steroid-refractory cases, targeted biologics such as infliximab, vedolizumab, or mycophenolate are used.
A critical concern is whether immunosuppression interferes with the anti-tumour benefit of immunotherapy. Current evidence suggests that corticosteroids used for irAE management do not significantly compromise treatment efficacy — reassuring for patients who worry that managing side effects means compromising their cancer treatment.
Prevention, Monitoring, and Patient Education
There is no reliable way to predict who will develop irAEs — they can occur at any time, from the first infusion to months after treatment has ended. However, the risk can be mitigated significantly through:
Baseline organ function testing before starting immunotherapy
Regular blood work — liver enzymes, thyroid function, kidney panels, cortisol levels
Patient education — empowering patients to recognise and report early warning signs
Prompt communication with the oncology team when new symptoms arise
Patients across Mysore city, Hebbal, and Nanjangud Road undergoing immunotherapy should maintain close follow-up with the best medical oncologist in Mysore to ensure that any emerging irAE is caught early and treated appropriately before it becomes a crisis.
Conclusion: Power and Responsibility
Immunotherapy represents one of the most exciting frontiers in cancer medicine — offering hope where little existed before. But that power demands respect. Immune-related side effects are real, sometimes severe, and occasionally fatal if ignored. The key is vigilance: regular monitoring, open communication with your oncology team, and an understanding that a new symptom during immunotherapy is never "just a coincidence" until proven otherwise.
With the right specialist support and timely intervention, the vast majority of irAEs are manageable — allowing patients to continue benefiting from one of oncology's most transformative treatments.
FAQs
Q1. Are immunotherapy side effects the same as chemotherapy side effects?
No. Chemo side effects stem from toxicity; immunotherapy side effects are caused by immune overactivation and inflammation in healthy organs.
Q2. How soon do immune-related side effects appear?
They can appear anytime — from the first infusion to several months after completing treatment. Vigilance is required throughout and beyond the treatment period.
Q3. Will I have to stop immunotherapy if side effects occur?
Not always. Mild side effects are managed without stopping treatment. Moderate to severe cases may require a temporary hold or permanent discontinuation, depending on severity.
Q4. Can immune-related side effects be permanent?
Most resolve with treatment. However, some endocrine effects — like hypothyroidism or adrenal insufficiency — may require lifelong hormone replacement.
Q5. Is immunotherapy available for all types of cancer?
No. Immunotherapy is approved for specific cancer types and stages. A consultation with a specialist will determine if it is appropriate for your diagnosis.
