Advances in cancer research have improved treatment outcomes for many cancers. However, most newly diagnosed cancers continue to be treated with conventional cancer therapies such as surgery, chemotherapy and radiation therapy. Immunotherapies are largely used to treat advanced cancers that have progressed after initial treatment.
Oncologists have differing views with regards to the impact of immunotherapy and other targeted therapies. While some oncologists vouch for their potential, others seem more or less uncertain of their benefits.
“[Immunotherapies are] of great promise. Responses are seen in hitherto unresponsive tumours. Long term outcomes are awaited,” says Prof Vaskar Saha, Senior Consultant at Department of Paediatric Haematology & Director of Tata Translational Cancer Research Centre, Kolkata.
Clinicians do endorse the benefits of immunotherapy in advanced cancers. “Immunotherapy is a relatively new treatment and many consider this as the 4th arm of cancer treatment — in addition to surgery, radiotherapy and conventional chemotherapy,” comments Dr Anil D’Cruz, Director- Oncology, Apollo Hospitals.
Many of these targeted agents have changed the landscape of cancer treatment, for example, Glivec (imatinib) for leukaemias and molecular targeted therapies in lung cancer. However a lot more needs to be done, including finding more accurate markers that can help triage patients who will benefit from this costly treatments, according to him.
“As of now, there is evidence only in the recurrent and metastatic cancers like head and neck, lung and many others. In this setting, it is beneficial in about 30% of patients. It is yet to be proven in the primary setting,” according to Dr Krishnakumar Thankappan, Professor, Head and Neck Surgery and Oncology, Amrita Institute of Medical Sciences, Kochi.
“Efficacy of immunotherapy is often unpredictable,” avers Dr Narayanankutty Warrier, Medical Director, MVR Cancer Centre and Research Institute, Kozhikode.
Various reasons have been proposed for the variability in patient response to cancer immunotherapies, including the need to identify additional biomarkers and cancer pathways, as well as tumour heterogeneity,
Listing the reasons, Warrier points to the variability in cancer type and stage and the underlying immunosuppressive biology of the cancer; difficulty in identifying clinically significant biomarkers; the need for more predictive biomarkers and identifying biomarkers that have predictive or prognostic value for use in selecting patients who will benefit from treatment with cancer immunotherapy. He points out that tumour heterogeneity impedes the efficacy, and leads to the development of resistance to drug treatment.
Today, a single type of cancer can be treated with chemo, targeted therapy and immunotherapy. Lung cancer is the best example. In the early 2000s, stage IV lung cancer patients would have been offered chemo alone, which would have given him 8 months of survival. Today, for some stage IV cancers, we can extend the survival for more than 2 years if we correctly sequence multiple modalities of therapy. That is really amazing, he adds.
Over and above, the prohibitive cost of immunotherapies is the foremost reason for not opting for treatment by most people. I-O is not covered by health insurers. They may sell insurance for Rs 50 lakh, but still immunotherapy is not covered, says Dr Warrier.
Dr R Sankaranarayanan, Senior Visiting Scientist, WHO-IARC, Lyon, France is also of the opinion that it is the cost factor that comes as a major hurdle in accessing treatment.
“At current costs, targeted therapies are unaffordable for most patients and public health services. The incremental increase in survival by a few weeks or months is not commensurate with their costs, toxicities and affordability,” he says. The key to improve survival rates is detecting cancer in early stages and effectively treating it with affordable and effective treatments. Targeted therapies are not cost-effective in most settings and the incremental benefit over and above standard treatment is negligible.
Meanwhile, Dr Warrier points to the paucity of awareness about these therapies as yet another hindrance. As far as primary care physicians are concerned, the concept of immunotherapy as a treatment modality is yet to reach them. Very often, patients go to them for an opinion when their oncologists suggest immunotherapy, and the primary care physician generally gives the answer that since it is stage IV cancer, there is not much hope. “A lot of awareness needs to be created among primary care physicians regarding immuno-oncology,” says Dr Warrier.