By Victoria Sahadevan Fossland, MD
Medical Writer

The Frontiers in Medicine series examines advances shaping the future of medicine. This post is the first of 2 about immunotherapy.

Approximately 40% of Americans will develop cancer during their lifetime. However, the risk of dying from cancer in America is roughly half of that (18% for women; 21% for men).1 Increased screening over the last 50 years has helped us identify and treat cancer at earlier stages so that one can now expect to outlive most malignancies. And as our understanding of cancer’s biology has deepened, treatment approaches have expanded, revolutionizing cancer treatment. Immunotherapy is one such approach.

What is immunotherapy?

The immune system continuously surveys the body for abnormal cells and substances to prevent infection, fight disease, and inhibit the proliferation of damaged or malfunctioning cells that can lead to cancerous growths. In fact, immune system cells are sometimes found around and within tumors.2 Cancer cells can evade and outsmart the immune system by sending signals to decrease immune system activity and create a microenvironment that favors their growth.2-4

Biologic therapies use live substances from living organisms. Immunotherapy is a type of biologic therapy that prevents, slows, or eliminates cancer growth and spread by using patients’ own immune system cells and pathways to their advantage.2-4

For example, allergy shots are a type of immunotherapy: a tiny amount of a substance that triggers a person’s allergic reaction is given to the patient to teach their immune system to reduce its response.5

When is immunotherapy used?

Doctors use immunotherapy with traditional cancer treatment strategies to improve clinical outcomes.6 Traditional cancer treatments target malignant cells themselves: surgery removes solid tumors; chemotherapy disrupts cancer cell replication; and radiation therapy damages the DNA of cancer cells. In contrast, immunotherapy augments the immune system’s ability to fight and destroy cancer cells. By combining treatment methods, tumors can be weakened and the immune system boosted to potentially eliminate cancer.7

Is targeted therapy the same as immunotherapy?

No. Targeted approaches use drugs designed to interrupt molecular pathways critical to tumor growth and maintenance. For example, monoclonal antibodies and small-molecule drugs are targeted therapies, typically lasting a few months.8 Like immunotherapy, targeted therapies can slow down biological pathways by interfering with proteins and receptors critical to tumor growth, maintenance, and spread.6 They can increase the immune response to tumors or “mark” cancer cells to enhance their detection and subsequent destruction.2,6,8

Immunotherapy carries these approaches further by teaching the immune system to develop enduring responses to cancerous growths well after the treatment period has ended.6

How has immunotherapy changed cancer treatment?

Immunotherapy provides an additional weapon against tumors that prove difficult to treat. In some cases, immunotherapy has enabled patients with metastatic cancer to be cured.7,9,10 To date, at least 15 different types of cancer have been successfully treated with immunotherapy.11

Immunotherapy is considered so promising that more than 70 immunotherapy drugs are being developed and more than 1000 immunotherapy clinical trials are underway across the US.11

In our next Frontiers in Medicine post, we’ll take a closer look at how immunotherapy works and consider additional disease candidates for immunotherapy treatment, future immunotherapy applications, and potential adverse effects that can occur when immunotherapy is used.


  1. Lifetime risk of developing or dying from cancer. American Cancer Society. May 12, 2022. Accessed June 22, 2022.
  2. Immunotherapy to treat cancer. National Cancer Institute. September 24, 2019. Accessed June 21, 2022.
  3. Immunotherapy. MD Anderson Cancer Center. Accessed June 21, 2022.
  4. Igarashi Y, Sasada T. Cancer vaccines: toward the next breakthrough in cancer immunotherapy. J Immunol Res. 2020.
  5. Allergy shots. Mayo Clinic. Accessed June 21, 2022.
  6. Immunotherapy for cancer treatment. Moffitt Cancer Center. Accessed June 21, 2022.
  7. Sharma P. What is the future of immunotherapy? MD Anderson Cancer Center. March 24, 2022. Accessed June 21, 2022.
  8. Targeted therapy to treat cancer. National Cancer Institute. May 31, 2022. Accessed June 21, 2022.
  9. Lesch S, Gill S. The promise and perils of immunotherapy. Blood Adv. 2021;5(18):3709-3725. doi:10.1182/bloodadvances.2021004453
  10. Study tests immunotherapy in people with cancer and autoimmune diseases. National Cancer Institute. August 26, 2019. Accessed June 21, 2022.
  11. Immunotherapy: precision medicine in action. Johns Hopkins inHealth. Accessed June 21, 2022.


Victoria Sahadevan Fossland, MD, is a general surgeon and medical writer of print-based, interactive learning, and multimedia projects. She writes clinical education pieces about a wide variety of diseases. Her work explains disease pathophysiology, treatment, clinical trial research details, and concerns that can arise from both physician and patient perspectives. Victoria has used her expertise in distilling medical knowledge into readily comprehensible and accessible learning solutions to write many valuable communications, learning modules, and workshops for Encompass, including the script for an award-winning video.