The emerging role of immunotherapy in head and neck squamous cell carcinoma (HNSCC) is the most common cancer in our country comprising more than one third cases of all cancers in India. Each year nearly 12 lakh new cases of cancer are diagnosed in our country – majority presenting in advanced stage 3-4. HNSCC includes a wide variety of tumours originating in the lip/oral cavity, hypopharynx, oropharynx, nasopharynx or larynx. It is the sixth most common malignancy worldwide, accounting for approximately 6 per cent of all cases and is responsible for an estimated 1–2 per cent of all cancer deaths.
HNSCC is caused by extensive use of tobacco ( gutka, khaini etc) and alcohol; however, more recently infection with high-risk human papillomaviruses (HPV) and especially type 16 has also been implicated in oropharyngeal cancer.
Evolving treatments
Most patients in our country present advanced stage of their disease and in such cases survival rates are low and associated with significant toxicities caused by currently available treatment strategies that include cancer chemotherapy and local radiotherapy. This underlines the urgent need for better treatment options.
It has been widely accepted that the immune system plays a crucial role in cancer development. Tumour cells evade immunosurveillance and proliferate even in the presence of immune cells around them. This occurs by exploiting inhibitory checkpoint pathways that suppress antitumour T-cell responses. If one is able to put brakes on these pathways, then the immune cells will get activated and thus kill the surrounding cancer cells. These immune drugs are called immune check point inhibitors. Following the increasing understanding of the underlying mechanisms behind control of malignancies by the immune system, the establishment of immune-based therapies has emerged as a promising approach for the treatment. immunotherapies are designed to target and harness the patient’s own immune system directly to fight cancer.
Immunotherapy in head and neck cancer can offer a better alternative to salvage chemotherapy options as the latter can be a very morbid treatment. When compared between each other, overall survival was significantly longer with immunotherapy and around double than that with standard therapy. The response rate is around 14 per cent with immunotherapy and treatment-related adverse events are also less with immunotherapies. There is no nausea, vomiting, bone marrow suppression and hair loss with immune drugs compared to standard-therapy.
To date, conventional treatment has mediocre results and prognosis in patients with advanced disease is dismal. There is a growing body of evidence that the immune system plays a pivotal role in oncogenesis and tumour evolution .Our better understanding of the mechanisms of immune escape has led to the development of novel immunotherapies that has shown initial promising results in many solid tumours including HNSCC.