Immunotherapy for Cancer Treatment Side Effects, Risks & Benefits

The immune system plays a crucial role in safeguarding the body against harmful germs and combating diseases. When an infection or disease occurs, the immune system is activated. Immunotherapy refers to a biological treatment method that harnesses the body's immune system to fight diseases. In the realm of cancer treatment, immunotherapy is increasingly favoured over traditional approaches like chemotherapy or radiation therapy.

It assists the immune system in recognizing and targeting cancer cells specifically, resulting in their destruction while minimizing harm to healthy cells in the body.

Types of Immunotherapy

Healthcare providers may use different types of immunotherapies to treat varied cancer types. Each type of immunotherapy targets different elements of the immune system.

Cancer immunotherapy types include:

• Checkpoint inhibitors
• Monoclonal antibodies
• Cancer vaccines
• Adoptive cell therapy
• Immune system modulators

Checkpoint Inhibitors

Checkpoint inhibitors therapy is a type of cancer immunotherapy. The therapy targets immune checkpoint proteins (the critical regulators of the immune system) from binding with their protein partners. This prevents the signal from being sent and, thus, subsequent attack on foreign cancer cells by the immune cells (T-cells). This therapy is effectively used to treat advanced stages of cancer where chemotherapy or surgery failed.

CAR-T Cell Therapy

Chimeric antigen receptor (CAR) T-cell therapy is an adoptive cell therapy that boosts the immune system’s ability to destroy cancerous cells. This therapy turns the T-lymphocytes or T-cells into more efficient cancer-fighting machines. Many CAR-T cells are grown in the laboratory and then injected back into the patient’s body to kill cancer cells.

This is effectively used to treat blood cancer.

Tumor-Infiltrating Lymphocytes (TILs)

Tumour-infiltrating lymphocytes are immune cells that can recognize and kill cancer cells. In cancer therapy, tumour-infiltrating lymphocytes are removed from a patient's tumour, grown in large numbers in laboratories, and then given back to the patient to help the immune system more effectively kill the cancer cells. FDA approves this therapy as a standard immunotherapy cancer treatment method.

Immune Checkpoint Inhibitor Antibodies

Immune checkpoint inhibitor antibodies are drugs that block checkpoint proteins synthesized by immune cells like T cells and some cancer cells. This inactivates the checkpoint proteins and facilitates the destruction of cancer cells by the T cells.

Immunotherapy for Cancer Treatment

Immunotherapy uses the body’s immune system to discover and destroy cancerous cells. The therapy may help some cancer patients live longer than expected with only radiation therapy or chemotherapy. It works by:

• Training the immune system to find and kill cancer cells.
• Helping the body to synthesize cancer-fighting immune cells and thus provide early recovery from cancer

Immunotherapy can be combined with other cancer therapies to efficiently treat metastatic cancer in the lung, breasts, skin, blood etc. When a tumour responds to immunotherapy, the remission tends to last for a long time (a year or more), contrasting to a response in chemotherapy (weeks or months). Also, with immunotherapy, tumours initially may swell due to engagement with the cancer cells; however, later, they shrink as cancer cells die. Thus, although immunotherapy is quite an effective treatment, certain cancers like pancreatic cancer, prostate cancer and glioblastoma are resistant to this approach.

Benefits of Immunotherapy for Cancer Treatment

Cancer immunotherapyoffers the likelihood of long-term cancer control in patients. The therapy trains the immune system to remember the cancer cells. This “immunomemory” provides long-lasting and permanent protection against cancer recurrence.

• Enhanced immune response: Immune checkpoint inhibitors mostly provide an enhanced immune response. The immune checkpoints are a normal part of the immune system and keep immune responses from being too overactive. However, blocking them with immune drugs bypasses the inhibition, allowing the immune cells to respond more strongly to cancer.
• Potential for long-lasting responses: The potential long-lasting response is observed in patients following immunotherapy compared to other treatments for two reasons.
• Firstly, some immunotherapy treatments help the immune system to stop or slow down the growth of cancer cells.
• Secondly, others facilitate the destruction of cancer cells by the immune system, thus stopping metastasis.
• Improved survival rates: Improved survival rates are observed following immunotherapy because:
• Immunotherapy targets only the immune system and not the healthy cells in the body.
• Cancer is less likely to return as the immune system memorises the cancer cells and attacks them if they ever reappear.
• It has lower side effects than other therapies.
• Personalized treatment approach: Cancer immunotherapy is personalised due to two reasons:
• In adoptive cell therapy, a person’s immune cells are isolated, grown in large numbers, and infused into the bloodstream to eliminate cancer.
• The discovery of personalised neoantigen cancer vaccines provides a highly specific immunotherapy cancer treatment by inducing cytotoxic T-cells to attack the patient’s cancer antigen.

Side Effects Immunotherapy for Cancer Treatment

Cancer immunotherapy has numerous side effects like fever, chills, fatigue, headache, etc., as the body’s immune system gets modified, thus causing enhanced responses.

Immunotherapy side effects are:

• Infection: Infections usually occur after CAR-T cell therapy. They occur soon after the infusion as infection-fighting immune cells may be weakened and exposed to other microbes when grown outside.
• Organ inflammation: Organ inflammation is quite common post-cancer immunotherapy. This occurs because the immune system gets boosted. Thus, they attack the healthy cells in the body, causing tissue inflammation. This response is called immune-related adverse effects experienced by 3.5% of the population post immune checkpoint inhibitor therapy.
• Fatigue: The precise biological mechanism by which cancer immunotherapy can cause fatigue remains unclear. However, certain inflammatory cytokines released aggressively post-immunotherapy have been shown to induce a sense of tiredness and fatigue. The cytokines modulate the signalling processes in the CNS and thus cause tiredness or fatigue.
• Nausea or vomiting: Immune checkpoint inhibitors often affect the gastrointestinal tract causing side effects like nausea and vomiting. It also causes inflammation of the colon, a condition called colitis, resulting in diarrhoea.

Risks of Immunotherapy for Cancer Treatment

Cancer immunotherapy doesn’t work on all kinds of cancer and for everyone receiving treatment. Alongside, most immunotherapy treatments can have many associated risks due to overactive immune responses.

• Immune-related adverse events (IRAEs): Immune-related adverse events are the inflammatory and auto-immune complications affecting different body parts due to cancer immunotherapy. Frequent IRAEs include gastrointestinal, endocrine and dermatologic toxicities.
• Infusion reactions: An infusion reaction is a hypersensitivity reaction that develops shortly after drug administration. Cancer immunotherapy like CAR-T cell therapy may lead to mild to moderate infusion reactions like chills, fever, hypotension, etc., as the body has a strong immune response to the immunotherapy cancer treatment that is given intravenously.
• Respiratory problems (cough, shortness of breath): Cancer immunotherapy, especially the immune checkpoint inhibitors, may cause pneumonitis, which is inflammation of the lungs in patients. This can induce cough, shortness of breath or breathing trouble in them.
• Liver inflammation (hepatitis): Cancer immunotherapy can trigger an immune response, leading to liver enzyme elevations that signal liver inflammation. These elevations are generally observed for two to three months after starting therapy.

Conclusion

Immunotherapy is a cancer treatment that uses the body’s immune system to identify and destroy cancer cells. It slows down cancer growth and encourages longer life expectancy in patients. However, not everyone with cancer responds to immunotherapy. Additionally, therapy has numerous side effects. Thus proper consultation with a healthcare provider can help anyone get the best cancer therapy their body needs.

Frequently Asked Questions

1. What stage of cancer is immunotherapy used?

Immunotherapy is usually recommended for patients with advanced cancer. However, it cannot completely cure cancer, but it definitely improves the quality and longevity of a patient's life.

2. Can immunotherapy cure stage 4 cancer?

Stage 4 cancer usually resembles metastasis or the spread of cancer throughout the body. Thus it is unlikely for any treatment to cure the cancer completely. However, patients receiving immunotherapy have a prolonged survival rate and improved quality of life.

3. Can cancer return after immunotherapy?

Immunotherapy highly reduces the risk of cancer recurrence. However, some cancerous cells may be left in the body, which might start growing back when the therapy stops.

4. Is immunotherapy better than chemo?

Cancer immunotherapy provides long-term protection against cancer by employing the immune system's ability to recognize and destroy cancer cells while minimally harming the healthy cells. However, chemotherapy treatments are harmful to healthy cells and are effective till the drugs remain in the body.

5. Can immunotherapy shrink cancer?

Immunotherapy causes initial swelling of cancer cells as the immune cells engage with them during the therapy. However, later they kill and destroy the cancer cells, thus inducing the shrinkage of cells or tumours.

6. Why does immunotherapy cause side effects?

Immunotherapy may cause the immune system to attack the healthy cells and thus induce changes in the body or how a person feels. These are called immunotherapy side effects which are different for everyone and depend on the specific type of immunotherapy they receive.