Prateek Tanmay
Television actor Dipika Kakar’s recent disclosure about experiencing side effects during immunotherapy has once again drawn public attention to a treatment that has transformed cancer care over the past decade. Unlike chemotherapy, which attacks rapidly dividing cancer cells, immunotherapy works by harnessing the body’s own immune system to identify and destroy tumours.
It has significantly improved survival for many patients with cancers such as lung, kidney, melanoma, bladder, head and neck, and certain gastrointestinal cancers. But because the treatment works by stimulating the immune system, it can sometimes trigger inflammation in healthy organs as well. While most side effects are mild and manageable, some can become serious if not recognised early, making regular monitoring throughout treatment essential.
“My immunotherapy procedure is going smoothly. The second cycle is done. This whole month has been crazy. After the first immunotherapy cycle, my body has been adjusting to the new chemotherapy cycles. There are side effects. After the first cycle, I got a viral fever, and I felt too low. After the second cycle, I am getting body rashes, and there is itching. I am getting used to this new normal. It has been 3-4 days since the second cycle, and I am dealing with the side effects,” said Kakar.
“Unlike chemotherapy, immunotherapy does not directly kill cancer cells. Instead, it empowers the patient’s own immune system to fight the cancer,” Dr Dipanjan Panda, Senior Consultant, Medical Oncology, Indraprastha Apollo Hospital, Delhi, told The Indian Express. Excerpts:
How does immunotherapy work?
Immunotherapy refers to a group of treatments that helps the immune system recognise and attack cancer cells more effectively. The most widely used drugs today are immune checkpoint inhibitors, which are molecular brakes. Think of the immune system as a car with brakes. Some cancers exploit these brakes to avoid being attacked. These drugs release the brakes, enabling immune cells to go after the cancer.
However, immunotherapy is not suitable for every patient or every cancer. Its effectiveness depends on the type and stage of cancer, tumour biology, biomarkers, overall health and how an individual’s immune system responds to treatment.
Why are the side effects different?
Because immunotherapy activates the immune system rather than directly damaging rapidly dividing cells, its side effects differ from those associated with chemotherapy. Instead of hair loss or severe suppression of blood counts, patients are more likely to develop what doctors call immune-related adverse events. These are conditions in which the activated immune system mistakenly attacks normal tissues.
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The most common side effects include fatigue, skin rash or itching, fever, joint and muscle pain, nausea, diarrhoea and reduced appetite. These are usually mild and respond well to supportive treatment.
Which organs can be affected?
In some patients, the immune system may begin attacking healthy organs, leading to inflammation in different parts of the body. The lungs may develop pneumonitis, causing persistent cough and breathlessness. The liver may become inflamed, resulting in abnormal liver function tests or jaundice. The intestines may develop colitis with severe diarrhoea, while the thyroid, adrenal glands and pancreas may be affected, leading to hormonal disturbances. Less commonly, the kidneys, heart, brain or nerves may also be involved.
Most patients tolerate immunotherapy well, and the majority of side effects are mild to moderate. Severe immune-related complications occur in only a small proportion of patients, but they require prompt recognition and treatment.
Why monitoring is crucial
Unlike chemotherapy, whose side effects usually follow a predictable timeline, immune-related reactions can occur at any stage — within weeks of starting treatment, several months later, or even after immunotherapy has been completed.
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We advise patients not to ignore persistent cough, breathlessness, severe diarrhoea, yellowing of the eyes or skin, unusual fatigue, severe headaches, blurred vision, new skin rashes or any unexplained symptoms. Early reporting allows doctors to identify whether the immune system is attacking healthy organs before permanent damage occurs.
Can these side effects be treated?
The reassuring news is that most immunotherapy-related side effects are reversible when detected early. Depending on their severity, doctors may temporarily pause treatment and prescribe corticosteroids or other immunosuppressive medicines to calm the immune response. Once the inflammation settles, many patients can safely resume immunotherapy, although some may need a different treatment strategy if severe toxicity develops.
Experiencing side effects does not necessarily mean the treatment is working better, nor does the absence of side effects mean it is ineffective. Every patient’s immune response is unique.
Immunotherapy has revolutionised cancer treatment and has helped many patients live longer with a better quality of life. With timely intervention, most side effects can be controlled, allowing patients to continue benefiting from one of the biggest advances in modern oncology.
