One of the cancer treatments, immunotherapy, is fast gaining prominence, what with a range of new immunotherapeutic strategies being available. However, a large population is still unaware about how cancer immunotherapies differ from the conventional chemotherapy.¹

The immune system is made up of white blood cells, organs and tissues of the lymph system and helps the body fight infections and other diseases. Usually, the immune system by itself detects and destroys abnormal cells including cancer cells. However, many a times abnormal or cancer cells find the mechanism to escape the immune system . This escape mechanism can be due to genetic changes which make cancer cells less visible to the immune system or by presence of proteins on the surface which can turn off immune cells.

History

The introduction of immunotherapy can be traced to the nineteenth century wherein the thought of immune system to treat neoplastic disease originated. Willhelm Busch and Friedrich Fehleisen were the pioneers in this field when they described an epidemiological association between immune status and cancer.² Later, William Coley, who is also called the ‘Father of cancer immunotherapy’ treated cancer patients with extracts of heat-activated S.Pyogenes and Serratica marcescens to boost immunity. However, lack of scientific rigour and reproducibility along with the discovery of radiotherapy and chemotherapeutic agents came in the way of making it a standard practice. The concept of immunotherapy resurfaced in the twentieth century when a connection was established between productive immune responses following tumoural adoptive transfer in mice and clinical reports of spontaneous regression of melanoma in patients with concomitant autoimmune disease. Immunotherapy was first approved in the US in 1990.³ Today it is used for treating various types of cancers such as lung, bladder, brain, breast, cervical, colon, head and neck, kidney, lymphoma, liver, leukaemia, ovarian, prostrate and skin.

Types of immunotherapy

Immunotherapy is a cancer treatment wherein your immune system is strengthened to fight cancer. It is a biological therapy in which substances made from living organisms are used to fight cancer.⁴

The various types of immunotherapy are:

Immune checkpoint inhibitors – these drugs block immune checkpoints and hence releases the brakes of the immune system allowing immune cells to act more strongly against cancer.

T-cell transfer therapy – Also called adoptive cell therapy, it is a treatment which boosts the natural ability of patients own T-cells to fight cancer. Immune cells are extracted from patients own tumor, which then altered in the laboratory to act better against patient’s tumor.

Monoclonal antibodies – These are immune system proteins created in the lab which are designed to bind to specific targets on cancer cells. They are the type of targeted therapy but some of the monoclonal antibodies tag the cancer cells so that they can be easily recognized by immune cells and hence leads to cancer cell destruction.

Treatment vaccines⁴ – They boost immune system’s response to cancer cells.

Immune system modulators – They enhance the body’s immune system against cancer.

The Process

Immunotherapy can be administered through:

Intravenous – Here immunotherapy drugs are injected directly into the vein.

Oral – Immunotherapy is available in the form of pills and capsules to be consumed.

Topical – It comes in the form of a cream to rub into the skin which is usually recommended for early skin cancer.

Intravesical – Here it is delivered directly into the bladder.

Side-effects

Though immunotherapy has successfully helped in the treatment of cancers, they have side-effects which are fewer than the one in chemotherapy. One of the side-effects are that the immune system at times gets so activated against cancer that it also acts against healthy cells and tissues in your body. So, it is advisable to look into the pros and cons of immunotherapy before opting for it.

Riferimenti:

1. Awareness and understanding of cancer immunotherapy in Europe – PubMed (nih.gov)
2. A guide to cancer immunotherapy: from T cell basic science to clinical practice | Nature Reviews Immunology
3. immunotherapy: Immunotherapy is gaining wider acceptance for treatment of different types of cancer, Health News, ET HealthWorld (indiatimes.com)
4. Immunotherapy for Cancer – NCI