KOCHI: hen diagnosed with cancer, Achuthan (name changed) from Palakkad district in Kerala learnt about immunotherapy, a new immunity boosting facility to cure the ailment, and decided to try a hand. Having undergone a cycle of treatment, the septuagenarian now finds it much comfortable. “I was comfortable after the injection. There was no pain, tiredness, nor any other difficulty that people who undergo chemotherapy experience. I felt the treatment was safer and after the blood test, I am waiting for the next cycle,” says Achuthan, who is undergoing treatment for the third stage of lung cancer.
The immune system in every human body comprises special cells that constantly patrol the body for intruders. When they come across a damaged or cancerous cell, they destroy it. This keeps cancerous tumours under check from growing. However, cancerous cells constantly look for ways to dodge immune system defences. Through immunotherapy, one can strengthen the immune system’s ability to fight cancer cells, apart from targeting and destroying specific proteins or receptors on cancer cells to prevent them from outsmarting immune system.
Immunotherapy has been a landmark discovery in cancer therapeutics, according to Dr Arun Philip, senior consultant, medical and hemato-oncology at Rajagiri Hospital, Ernakulam. “It has changed the way we treat many advanced cancers. These drugs are designed to stimulate the body’s anti-tumour immune response and thereby causing tumour kill,” he said. Dr Raghunath SK, senior consultant and director of uro-oncology and robotic surgery at HCG Cancer Centre in Bengaluru, said immunotherapy was a revolutionary approach to combat cancer by leveraging the body’s immune defences.
“Unlike conventional treatments like surgery or radiation, which directly target cancer cells, immunotherapy works by enhancing the immune system’s ability to identify and eradicate threats. It is akin to providing specialised training and advanced weaponry to bolster the immune army’s efforts in the fight against cancer,” he said.
In comparison with chemotherapy
Chemotherapy is the most common type of treatment that comes to one’s mind for cancer, in which drugs are used to kill the cancer cells in the body. In comparison, immunotherapy uses the body’s immune system to stop and kill cancer cells, and also has the potential to prevent and cure cancer.
Developed in the late 1800s by William Bradley Coley, an American surgeon and oncologist, immunotherapy, also known as immune checkpoint inhibitors, works by targeting the tumour by using the immune system. Earlier attempts to modulate patients’ immune systems to cancer are attributed to two German physicians - Feheleien and Busch.
Chemotherapy drugs can be used alone or in combination to treat a wide variety of cancers. Though chemotherapy is an effective way to treat many types of cancer, it also carries risk of side effects which can range from mild and treatable, to serious complications.
How the remedy works
Dr Jaisankar P, consultant in medical oncology at Lisie Cancer Centre, said immunotherapy is more biological. “It mainly belongs to three categories - anti-PD1, anti-PDL1, and anti-CTLA4. The basis of modern immunotherapy is the identification of PD1, PDL1 and CTLA receptors, and their role in immune evasion by tumour cells. In PD1, PDL1 interaction, multiple drugs that block CTLA receptors were developed. The drugs which bind to these receptors and block their activity are broadly termed immune checkpoint inhibitors,” he said.
Immune evasion or antigenic escape is a process by which a pathogen can bypass or evade the immunogenic response of a host’s cells and continue its growth and transmission. “In comparison to conventional chemotherapy drugs, they do not directly destroy cancer cells and do not have much toxic effects on the normal healthy cells, hence are supposed to be safer,” added Dr Arun.
This mostly works in tumours which produce the most number of tumour antigens, according to Dr Jaisankar. Though the therapy was not familiar to people earlier, with increased awareness, the popularity of the treatment has increased and it is used to treat tumours in several people. “Earlier, immunotherapy was not widely used as the indications were limited and the cost was high. But now with increased awareness and reduction in cost, the use has gone up. Immunotherapy can be used even in patients who are not fit to receive chemotherapy as side effects are much lower,” he said. (With inputs from Rishita Khanna @ Bengaluru)