Immunotherapy Explained: How It Helps the Immune System Fight Cancer

What Is Immune Therapy?

Immunotherapy is an area of cancer treatment that uses your immune system against your cancer. The body has its own immune system to identify and destroy harmful things inside the body, such as bacteria, viruses and abnormal cells. Sometimes, cancer cells develop ways to hide from the immune system or suppress its activity. Immunotherapy works by helping your body overcome these obstacles by improving, redirecting, or restoring the immune system's ability to recognise and destroy cancer cells.

According to studies, "Cancer immunotherapy harnesses the body's immune system to fight cancer and achieves an average 30% objective response rate across solid tumors. In Stage 4 melanoma, combination therapies deliver a 52% 5-year survival rate, with over 40% surviving beyond 10 years. For advanced NSCLC, pembrolizumab provides a 23% 5-year survival rate, while combination approaches achieve up to 25% pCR rates. Durable remission occurs in 15-20% of patients and can reach 80% in cancers with biomarkers such as dMMR."

Immunotherapy will not directly attack the tumour; instead, it will help to enhance your body's own defence mechanisms against the tumor so that your immune system can work more efficiently in killing it.

How does the Immune System Usually Defends Against Cancer?

The immune system continually scans the body for abnormal cells, and specialised immune cells, such as T-cells, can identify and destroy them.

However, cancer cells can change quickly. They can do this by:

Camouflaging themselves to look like normal cells
Making signals to turn off the immune system
Making a shield to protect the tumor
Hiding from the immune system

Because of this, tumors grow and spread even when the immune system is working. Immunotherapy works to remove these barriers, allowing the immune system to recognize cancer as a threat again.

Types of Immunotherapy Used to Treat Cancer

Checkpoint Inhibitors

One of the most commonly used types of immunotherapy is checkpoint inhibitors. The immune system has "checkpoints" that help control its activity and protect healthy cells. Some cancer cells exploit these immune checkpoints to evade immune attack.

Checkpoint inhibitors block checkpoints, allowing the immune system to recognise and kill cancer cells more easily. These therapies have become important treatment options for many different types of cancer.

Monoclonal Antibodies

Monoclonal antibodies are laboratory-produced protein molecules designed to bind a specific target. When these antibodies attach themselves to cancer cells, they can:

Flag the cancer cell to be killed by the immune system
Block signals that cause cancer cells to grow
Send therapies targeted at killing cancer cells directly to the affected area

Immunotherapies like this have proven to help the immune system identify cancer cells more quickly.

CAR T-Cell therapy

CAR T-Cell therapy represents an advanced approach to personalised immunotherapy. In CAR T-Cell therapy:

T-cells from a patient will be collected from their bloodstream (using apheresis), modified with CARs in the laboratory to better recognise the patient's cancer cells, and expanded before the engineered T-cells are returned to the patient's body.
These CAR T-cells will be able to target and attack the patient's cancer with greater efficacy than unmodified T-cells.
CAR T-cell therapy is most successful for certain blood cancers like leukaemias, lymphomas, and multiple myelomas.

Cancer Vaccines

Therapeutic Cancer Vaccines can be given to patients to stimulate the immune system against certain cancer targets. They help the immune system recognise and attack cancer cells, whereas most preventive vaccines protect the host against infectious disease.

Research continues to develop new immunotaxonomies based on vaccine technology for a variety of cancers. Immunotherapy is now being used or approved for use in the following cancer types:

Melanoma
Lung
Kidney
Bladder
Head and neck
Hodgkin Lymphoma
Certain gastrointestinal cancers
Some blood cancers

Not every individual or cancer will respond well to using an immune system modulator (immunotherapy). There are many different factors used to help make decisions about treatments for patients, including things like: how many times the tumor grew; what treatments have been included so far; and what specific type of biomarker is present.

Benefits of Immunotherapy

Immunotherapy has significant benefits compared with traditional approaches to treating cancer. These benefits may include:

A more targeted response of the immune system
The potential for a longer-lasting effect of the treatment after completion of treatment
Ability to treat advanced forms of the disease
Possible improved prognosis in some patients
Decreased destruction of certain healthy tissue types

In addition, it may be possible for the immune system to continue working against the cancer even after treatment has been completed due to the presence of "memory" of the cancerous cells in the immune system.

Side Effects

Although many patients tolerate immunotherapies well, they can also cause side effects. As the immune system is activated by the treatments, there is potential for immune cells to damage other tissues in the body. Side effects from immunotherapies may include:

Fatigue
Rashes
Diarrhea
Joint pain
Fever
Inflammation in organs (lungs, liver, or thyroid)

Most side effects can be managed effectively when identified early in treatment, which is why it is important that patients are monitored regularly throughout their course of treatment.

Future of Immunotherapy

Immunotherapy is currently one of the fastest-growing fields in cancer research. Researchers are exploring:

New checkpoint inhibitors
Individualized vaccines for cancer
Combination therapies
Enhanced CAR T-cell technologies
Biomarkers that predict response to treatment

Researchers are also exploring ways to combine immunotherapy with chemotherapy, radiation therapy, targeted therapy, and surgery to further improve outcomes. As understanding of the immune system grows, immunotherapy is expected to play an increasingly important role in cancer care.

Conclusion

Immunotherapy represents a major advancement in the fight against cancer. By helping the immune system recognise and attack cancer cells, these treatments offer a different approach from traditional therapies. From checkpoint inhibitors and monoclonal antibodies to CAR T-cell therapy and cancer vaccines, immunotherapy has transformed treatment options for many patients.

While it may not be suitable for every cancer type, ongoing research continues to expand its potential. As innovations emerge, immunotherapy is expected to remain a cornerstone of personalised and effective cancer treatment.

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Frequently Asked Questions

Immunotherapy is commonly used to treat melanoma, lung cancer, kidney cancer, bladder cancer, head and neck cancers, Hodgkin lymphoma, multiple myeloma, leukaemia, and certain gastrointestinal cancers.

The cost of immunotherapy in India varies depending on the medication, cancer type, and treatment duration. Costs typically range from USD 3,000 to USD 5,000 per cycle.

Treatment duration varies from a few months to several years. Some patients receive immunotherapy every 2-6 weeks, while others continue treatment until the cancer stops responding or side effects become significant.

Success rates vary by cancer type. Studies show that immunotherapy achieves an objective response rate of 30% to 50% across many solid tumors, with significantly higher responses in selected patients with favourable biomarkers.