IMMUNOTHERAPY IN CANCER TREATMENT

Dr Rahul Kulkarni - Medical Oncologist

What is Immunotherapy?
 
Cancer immunotherapy is the artificial stimulation of the immune system to treat cancer. It helps in improving the immune system's natural ability to destroy the cancer cells.In 2018,researchers Dr.james P.Allison of University of Texas MD Anderson Cancer Centre,and Dr.Tasuku Honjo of Kyoto university Japan, were awarded Nobel Prize for revolutionary discovery of Immunotherapy
 
How does Immunotherapy work?
 
Even though the immune system can prevent or slow cancer growth, cancer cells have ways to avoid destruction by the immune system. This generally happens because cancer cells :

     1) Have genetic changes that make them less visible to the immune system.
     2) Have proteins on their surface that turn off immune cells.
     3) Change the normal cells around the tumor so they interfere with how the immune system responds to the cancer cells.

Immunotherapy helps to block these mechanisms of evading the immune system and inturn stimulates immune system to mount an attack on cancer cells.
 
What kind of cancers can be treated with Immunotherapy?
 
Currently immunotherapy is approved for use with strong evidence in Lung cancer, Melanoma, Kidney cancer, Bladder cancer, Breast Cancer, Head and neck Cancers and Gastrointestinal Cancers. Further trials are ongoing  for its use in many other cancers.
 
When is immunotherapy recommended in cancer treatment?
 
Currently Immunotherapy is only recommended in advanced /metastatic cancers and that too in selected indications and patients.Immunotherapy is not a substitute for definitive modalities of treatment like Curative Surgery,radiation or curative chemotherapy.
 
How is Immunotherapy administered?
 
Immunotherapy is administered via intravenous route in the form of infusion. It is recommended to be administered under guidance and supervision of trained Medical Oncologist who is expert in handling the drug and assessing the response and manage the effects/side effects.
 
Can immunotherapy work in all Cancers?
 
There are certain biomarkers for predicting response to immunotherapy like testing for PDL1 receptor expression, Microsatellite instability testing etc. Hence use of immunotherapy is not recommended blindly for all. Please consult your Medical Oncologist before going for immunotherapy to understand the likelihood of benefit.
 
Is Immunotherapy always better than Chemotherapy?
 
This is not true in all patients. In properly selected patients and after proper testing of biomarkers as described above, Immunotherapy may be better either alone or in combination with chemotherapy in terms of response rates or overall survival. However in other situations of advanced cancers still chemotherapy remains the backbone of systemic treatment. In other situations, targeted therapy may be more beneficial if suitable targetable mutation is present in the tumor cell.
 
Is Immunotherapy free of side effects?
 
Immunotherapy does not have typical side effects like that of chemotherapy like hair loss, vomiting, low blood counts. As a general rule immunotherapy is very well tolerated. However immunotherapy has its own set of side effects due to its effect on immune system and in some patients it can lead to flare of autoimmune diseases, Pneumonitis, diarrhoea, autoimmune anemia, endocrine dysfuctions etc. Hence always consult your medical Oncologist and discuss about the same before opting for immunotherapy.
 
How do we know immunotherapy is working?
 
Generally immunotherapy takes 3-4 months before the responses can be seen. The response can be assessed by CT/PETCT scans. Sometimes in the initial period there may be radiological increase in tumour but the patient may feel subjectively well. This phenomenon is called ‘Pseudoprogression’ which can be seen with immunotherapy. However it has to be properly analysed by your treating medical Oncologist.
 
How many cycles of immunotherapy does patient need?
 
Generally we need to give minimum 3-4 cycles of immunotherapy before we can expect any response. If there is response to treatment then ideally we need to continue immunotherapy till the patient is getting benefit and tumour is responding. However there are some reports which state that the benefit of immunotherapy may continue for sometime even after stopping after prolonged treatment. This decision should be taken after consultation with your Medical Oncologist.
 
Can Immunotherapy Cure cancer?
 
Currently there is no evidence that immunotherapy can cure cancer. Since immunotherapy is used in advanced and metastatic cancers, complete eradication of cancer cells from the body to call it as cure is not possible. However if immunotherapy works well then it can provide long term progression free and overall survival to cancer patients with good quality of life.
 
What is the cost of Immunotherapy?
 
At present immunotherapy is an expensive treatment option with approximate cost of treatment ranges from 1 to 4 lakhs per cycle. Hence proper selection of patient and use of immunotherapy in right indication and right patient is of utmost importance.
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Disclaimer: The information provided here should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. The information is provided solely for educational purpose and should not be considered a substitute for medical advice.