Cancer and the Immune System

The immune system protects the body from foreign invaders, such as bacteria, viruses, fungi and toxins. However, the immune system struggles to defend the body against cancer – especially on its own.

Cancer cells have the ability to infiltrate the immune system by avoiding its defensive line of cells. This will compromise the immune system and cause it to stop functioning properly.

This blog explains what the immune system is, how cancer diminishes its impact, and what medicines like immunotherapy do to empower the immune system against cancers like mesothelioma.

 

What Is the Immune System?

The immune system is a strong and complex network of cells, organs, blood vessels, lymph nodes and more. There are five cells in the immune system responsible for fighting off cancer and infection: macrophages, dendritic cells, natural killer (NK) cells, B-cells and T-cells.

The immune system is also made up of the lymphatic system, which is a network of vessels and lymph nodes. These nodes help produce T cells to fight infections and diseases, and the vessels speed up the immune response.

Although there is a substantial defense team within the immune system, it seems to fall short when facing cancer cells.

 

How Does Cancer Impact the Immune System?

The immune system is always on high alert for any signs of danger, like bacteria and viruses. Tumors, however, can often bypass the immune system and expand uncontrollably. When the immune system becomes overpowered by a malignant tumor, it can no longer accurately identify and respond to threats. 

 

Subduing Our T cells

In order to combat intrusive cells and tumors, the immune system relies on specialized cells known as T cells, which are responsible for recognizing and attacking invaders. The immune response begins when these T cells encounter antigens – molecules on the surface of foreign invaders such as bacteria or viruses. Once an antigen has been identified, a series of chemical signals are sent out by T cells, activating other immune cells to respond and eradicate the pathogen.

Just as the immune system is smart and powerful, cancer cells are, too. For example, they may produce a molecule that masks the presence of an antigen, preventing it from being recognized by T-cells. Sometimes, cancer cells may produce chemicals or proteins posing as an almost “invisibility cloak” for themselves, hiding them from T cells, so they can continue to grow and divide unimpeded.

 

Cancer and Immunoediting

While evading the immune system’s detection is one aspect, cancerous tumors can also actively suppress it. This is called immunoediting, a process in which the tumor releases molecules that both inhibit the function of certain immune cells and activate others that can be beneficial to its growth and survival. In some instances, cancer cells may release a protein stimulating the activity of regulatory T cells, which prevents other immune cells from recognizing and attacking tumor cells.

Just as current therapies, like chemotherapy, can temporarily disrupt some of these defense mechanisms, cancer has also found ways around these treatments. Tumors may develop resistance to chemotherapy by increasing the expression of a gene called P-glycoprotein (Pgp), which pumps chemotherapeutics out of the cell before they have time to have any effect.

 

Can Cancer Treatment Weaken the Immune System?

The effects of cancer alone can be detrimental to the body, but cancer treatment can also have long-lasting effects on the body and the immune system.

There are many forms of cancer treatment, all with different approaches. Each type of treatment has different effects on the body and the immune system. 

Chemotherapy drugs kill fast-growing cells, such as cancer cells, but chemotherapy may also kill fast-growing healthy cells. The body’s bone marrow contains fast-growing healthy cells, which produces immune cells. If chemotherapy attacks the healthy bone marrow cells, the immune system will not be able to perform to the best of its ability, leaving you susceptible to illness, bacteria and other threats.

Surgery, especially major cancer surgery, can negatively affect the immune system. Cancer surgeries are often aggressive approaches to cancer treatment and require extensive recovery time, specifically for preventing infection and proper healing of wounds and incisions.

Radiation therapy exposes cancer cells to energy waves that can kill or stunt the cells growth. Radiation will kill cancer cells, but it may also damage healthy cells that could affect the rest of the body’s functionality.

 

Immunotherapy Treatment Supports the Immune System Against Cancer 

Although most cancer treatments can negatively affect the immune system, immunotherapy treatment enables the immune system to properly fight off foreign invaders, like cancer cells. Immunotherapy works with the immune system to increase functionality and fight off cancer cells.

Here are some ways immunotherapy drugs fight cancer: 

• Attach to or kill cancer cells, which releases previously hidden proteins and alarms the immune system
• Helps the patient’s immune cells recognize cancerous antigens and target cells with similar antigens
• Attaches to proteins on cancer cells and signals to the immune system to respond
• Creates more effective immune cells to fight cancer

Immunotherapy has similar side effects to chemotherapy, but they often present themselves less often and as less severe. Some side effects of immunotherapy may be fatigue, nausea, dizziness, weakness, body aches and skin rashes. 

Cancer specialists, such as doctors specializing in treating mesothelioma, often compare immunotherapy and chemotherapy to determine the best treatment plan. Most studies show patients respond better to immunotherapy treatments versus chemotherapy.

 

How To Boost the Immune System After Cancer Treatment

It is important to maintain a healthy lifestyle during and after cancer treatment. By eating a balanced diet, resting well, and exercising regularly, you can improve your chances of recovery and potentially speed up your recovery time. 

A few ways to boost the immune system after cancer are: 

• Eating a balanced diet 
• Exercising regularly 
• Staying hydrated
• Minimizing stress
• Maintaining a healthy sleep schedule
• Reducing alcohol consumption 
• Eliminating a smoking habit   

Cancer can have long-lasting effects on the body and the immune system. It is an aggressive illness composed of intelligent cells that know how to survive in the body.

Treatments for cancer can take a toll on the immune system, causing it to lose functionality. Not all cancer treatments will damage the immune system, but there are risks. Maintaining a healthy lifestyle will help improve your immune system after cancer treatment.