Cancer Immunotherapy — Part 1: The Basics

Cancer immunotherapy uses the immune system or the body’s defense system to fight cancer. Before learning more about immunotherapy, you may want to read a quick overview of how the immune system works.

Immune System Overview

The immune system protects the body against diseases. Immune system cells called antigen-presenting cells patrol the body. When antigen-presenting cells find foreign cells, such as viruses and bacteria, they send a signal to special cells called T-cells, which attack the foreign cells. After all foreign cells have been killed, an immune system regulator called a checkpoint sends a signal to T-cells to stop their attack. This prevents T-cells from killing healthy cells.

What is immunotherapy for cancer?

Cancer cells are different than viruses and bacteria because they disguise themselves as normal, healthy cells. Antigen-presenting cells are not able to detect cancer cells, so a signal is never sent to T-cells. Thus, cancer cells multiply and spread and cancer progresses into more serious stages.

Immunotherapy stops immune cells from being tricked. There are different types of cancer immunotherapy. Each helps the immune system recognize cancer cells and start an immune response against them. This treatment approach is new and promising because it uses the body’s own resources, rather than surgery, radiation, or chemotherapy, to treat cancer. In many cases, this means there may be less unwanted treatment side effects.

How effective is immunotherapy?

Cancer immunotherapy may help cancer go into remission, or even cure it in some cases.  It may not work for all patients and all cancers. And because it is a relatively new treatment option, more research needs to be done to determine exactly which patients can benefit.

Still, there are certain tests that doctors can perform that may help them decide if immunotherapy can help a patient. Protein level tests and genetic tests are the two most common. High protein levels and DNA changes in cancer cells may predict that cancer will respond well to immunotherapy.

What is the difference between immunotherapy and other types of cancer treatments?

Each cancer treatment option works differently. The five treatment options are:

  1. Surgery. Cancer tissue is surgically removed.
  2. Radiation therapy. X-rays break DNA in cancer cells, which prevents them from growing and spreading.
  3. Chemotherapy. Drugs destroy cancer cells.
  4. Targeted therapy. Drugs target cancer cells’ genes and proteins to stop them from working properly, which can stop cells from growing, or even kill them.
  5. Immunotherapy. Different types of treatments are used to start an immune response against cancer cells.

Certain treatments may be used for certain cancers. In some cases, multiple treatments may be used.

Distinguishing features of each type of cancer treatment are:

  • Surgery may be effective for some early stage cancers
  • Radiation therapy and chemotherapy destroy healthy cells, which may cause unpleasant side effects
  • Targeted therapy and immunotherapy may only be effective for some patients and some cancers

A board-certified and fellowship-trained oncologist works with patients to find the most appropriate treatment option(s).

What types of cancer can be treated with immunotherapy?

Cancer immunotherapy has been tested on many of the most common types of cancer. An oncologist may recommend immunotherapy to treat:

  • Bladder cancer
  • Breast cancer
  • Head and neck cancer
  • Kidney cancer
  • Lymphoma
  • Prostate cancer
  • Small cell lung cancer
  • Melanoma/ Skin cancer

Research is being done to test immunotherapy on other types of cancer.

How is immunotherapy treatment given?

Cancer immunotherapy treatment is given at an oncologist’s office or an outpatient hospital unit. An overnight hospital stay is not necessary. Treatment may be administered:

  • Intravenously
  • Orally
  • Topically (for skin cancers)
  • Intravesical (through the bladder)

The patient’s response to treatment is closely monitored. Physical exams, blood tests, and scans are performed to see if cancer cells are responding to treatment.

How long does it take for immunotherapy to work for cancer?

Depending on the type of immunotherapy, treatment may be given daily, weekly, or monthly. There may be a break in treatment to give cells a chance to rest. Another therapy cycle may start after the break. The number of cycles a patient receives depends on the type of treatment and the type of the cancer. In some cases, immunotherapy may be combined with other cancer treatments.

The amount of time it takes for cancer immunotherapy to work is different for every patient. As previously mentioned, each patient’s response to treatment is closely monitored. Patients visit their oncologist frequently while undergoing treatment. The oncologist asks the patient questions about their symptoms and health. Answers to the questions and the medical study results give the oncologist important information about how well the immunotherapy is working.

More about cancer immunotherapy

This article is the first of a three-article series on cancer immunotherapy. In the next article, you will learn more about different types of immunotherapy in detail.


National Cancer Institute: “Immunotherapy to Treat Cancer

Cleveland Clinic: “Immunotherapy: Is It Right for Your Cancer Type?

WebMD: “How Immunotherapy Works to Kill Cancer Cells

Dr. Kenneth Blankenstein, M.D.
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