Immunotherapy is a treatment or intervention designed to help the body’s immune system fight cancer. It does not directly attack cancer cells but focuses instead on helping other cells – called immune cells – detect and destroy cancer cells.
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A definition of immunotherapy

Immunotherapy was first used as a cancer treatment about a century ago. A few early studies revealed that deliberately infecting certain cancer patients stimulated their immune system and positively impacted their cancer. As science progressed and effective and accessible treatments such as chemotherapy and radiotherapy were developed, immunotherapy was temporarily shelved. The first trials aimed at prompting the immune system to act on cancer tumors were performed in the 1950s, after which came immune system interventions such as bone marrow transplants.

Immune system stimulation as a means of destroying cancer tumors was thrust into the spotlight in the early 2000s, and quickly proved a promising avenue for scientific research.


Immunotherapy is now on the verge of becoming one of the cornerstones of modern-day oncology, with various parties speaking of advanced immunotherapy and personalized or precision medicine. But to better grasp the role of immunotherapy in an oncology setting, we need to first understand the workings of the human immune system.

The role of the immune system is to protect the body.

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It is a treatment that allows the body’s cells to fight cancer cells more effectively.

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Interferon alpha (Intron A, Wellferon), interleukin-2 (Proleukin), intravesical bacillus Calmette-Guérin (BCG) treatment, immune checkpoint inhibitors…

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Immunotherapy is a very active area of research. There are several types of treatments for the same cancer and for different cancers.

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With the recent development of many immunotherapies, including checkpoint inhibitors, several types of cancers are treated with immunotherapy.

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Immunotherapy treatments in oncology can have side effects that are significantly different from those of other cancer treatments such as chemotherapy or radiotherapy.

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Institut National du Cancer – Médecine de précision : thérapies ciblées et immunothérapie spécifique

InfoCancer – Immunothérapie 

Canadian Cancer Society – Immunotherapy 

American Cancer Society – Immunotherapy​ 

La ligue contre le cancer – L’immunothérapie 

National Cancer Institute – Immunotherapy to Treat Cancer​

Guides prepared for patients :

European Society for Medical Oncology – Les effets secondaires liés à l’immunothérapie

Société leucémie et lymphome Canada – L’immunothérapie 

CHUM – L’immunothérapie pour traiter le cancer 

All of the sources used to prepare this document can be consulted by communicating with the Quebec Cancer Foundation.

To find out more

To obtain more detailed information on immunotherapy and some tips on how to feel better, call the Info-cancer Hotline at 1-800-363-0063 to talk to a nurse or documentalist.

Borrow one or more books on the subject free of charge from our Info-cancer Library (available in French only).

Cancer treatments


Managing side effects of cancer and treatments

Cancer treatments are often accompanied by side effects, which manifest as symptoms of physical, and even psychological, discomfort.

Surgical Oncology

Surgical oncology is the branch of surgery concerned with the diagnosis and treatment of cancer. It is the oldest form of cancer treatment.

Precautions to take when one has cancer

While cancer treatments are essential to allow the patient to confront this health challenge, they can unfortunately result in a weakened immune system.


Radiation therapy involves the use of X-rays, gamma rays, electrons and other forms of high-energy radiation. The treatment is painless and does not last long, from one to five minutes. In fact, the waiting and preparation phases often take longer than the treatment itself, about 10 to 15 minutes.


Chemotherapy is a systemic treatment, that is to say, it can reach all parts of the body and destroy cancer cells, even microscopic ones, wherever it finds them.

Hormone therapy

Hormone therapy is a treatment that changes the level of hormones in the body.