Immunotherapy for Cancer: What It Is, Benefits, Side Effects and More

Introduction

After a cancer diagnosis, hearing that immunotherapy for cancer is an option may leave you wondering how it is different from chemotherapy and what the treatment will involve. Immunotherapy is a cancer treatment that helps the body’s immune system recognise and fight cancer cells¹.

Understanding how it works, which cancers it may treat, and the different types of immunotherapies can make the treatment easier to understand. Knowing how immunotherapy is given, along with its benefits, possible side effects, and when to consult a doctor, can also help patients and families make informed decisions about cancer care.

What Is Immunotherapy for Cancer?

Immunotherapy is a type of cancer treatment that supports the body’s immune system in finding and fighting cancer cells. The immune system normally protects the body from infections and other harmful substances. However, cancer cells can sometimes avoid or weaken the immune response, allowing them to continue growing. Immunotherapy aims to improve the body’s ability to respond to these abnormal cells¹.

How Does Immunotherapy Work?

Immunotherapy helps the immune system respond to cancer more effectively. It acts by modifying, enhancing, or redirecting immune responses against cancer.

The main ways immunotherapy may work include:

• Removing the Immune System’s “Brakes”: Some cancer cells use certain signals to stop immune cells from attacking them. Certain immunotherapies block these signals, allowing immune cells to stay active against cancer.
• Helping the Immune System Recognise Cancer: Some treatments make cancer cells easier for the immune system to identify and target.
• Strengthening Immune Activity: Certain immunotherapies boost the activity of immune cells or provide immune-related substances that help the body fight cancer.
• Bringing Immune Cells Closer to Cancer Cells: Some immunotherapies act as a bridge between immune cells and cancer cells, bringing them together so that the immune cells can attack the cancer more directly.
• Using Modified Viruses to Trigger an Immune Response: Some treatments use specially modified viruses that can infect and destroy certain cancer cells. This can also release signals that help the immune system recognise and attack other cancer cells³.

Which Cancers Can Immunotherapy Treat?

Immunotherapy is used for several types of cancer, but its use depends on the specific cancer, its stage and characteristics, and the treatment being considered. It may be used for cancers such as:

• Bladder Cancer: This type is commonly treated with immunotherapy.
• Breast Cancer: Used for certain types, such as triple-negative cancer (a type without oestrogen, progesterone, or HER2 receptors).
• Cervical Cancer: Used when the cancer is recurrent, persistent or has spread to other body parts or organs (metastatic).
• Colorectal Cancer: Used for certain tumours with certain DNA-repair changes.
• Oesophageal Cancer: Used during the advanced stage or before or after surgery.
• Head and Neck Cancers: Used along with surgery/radiation for certain advanced tumours, and for recurrent or metastatic tumours, specifically those positive for the biomarker PD-L1.
• Kidney Cancer: Given alone or alongside targeted therapy.
• Liver Cancer: Used especially during advanced stages in combination with targeted therapy.
• Lung Cancer: Used for some specific types, including non-small cell lung cancer.
• Blood Cancer: Used for certain types such as leukaemia, lymphoma, and multiple myeloma.
• Skin Cancer: Used for both pigment-producing (melanoma) and non-pigment-producing (non-melanoma) types⁴.
• Ovarian Cancer: May be useful in selected cases, such as recurrent cancer or when the tumour has certain biomarkers, such as MSI-H/dMMR or TMB-H^4,5.
• Pancreatic Cancer: May be useful for uncommon tumours/cancers that have DNA-repair biomarkers such as MSI-H, dMMR or TMB-H.
• Prostate Cancer: Particularly useful during advanced stages and for cancers with DNA-repair biomarkers or cancer cells that have a large number of DNA changes.
• Stomach/Gastroesophageal Cancer: Useful during advanced stages, especially when tumours have DNA-repair-related biomarkers or PD-L1 proteins on their surface.
• Uterine/Endometrial Cancer: Used for recurrent cancers or during advanced stages, especially if they have DNA-repair-related markers⁴.

Types of Immunotherapies for Cancer

Several types of immunotherapies can help the immune system fight cancer. The main types include:

• Immune Checkpoint Inhibitors: These medicines block certain pathways (immune checkpoints) that normally prevent immune cells from becoming too active. By blocking these signals, they can help immune cells stay active and attack cancer cells¹.
• T-Cell Transfer Therapy: In this treatment, doctors collect T cells (particularly the CAR-T cells), a type of immune cell, from the patient’s blood using a procedure called leukapheresis. The cells that can best fight the cancer may be selected or modified in a laboratory, multiplied, and then returned to the body to help attack cancer cells^1,6.
• Monoclonal Antibodies/Therapeutic Antibodies: These are laboratory-made proteins; some of these can help immune cells recognise and attack cancer cells.
• Cancer Treatment Vaccines: Unlike vaccines that prevent infections, these vaccines are designed to help the immune system recognise and respond to cancer cells.
• Immune System Modulators: These treatments change or strengthen the activity of the immune system. Some act on specific parts of the immune response, while others show a general effect¹.

Note: Immunotherapy works by changing or strengthening the body’s immune response. Because of this, some treatments may also cause the immune system to attack healthy cells or organs. For example, checkpoint inhibitors can sometimes affect normal organs, while CAR-T cells may attack healthy cells that carry the same target as the cancer cells.

How Is Immunotherapy Given?

The way immunotherapy is given depends on the specific medicine and the type of cancer being treated. The following explains how immunotherapy is done:

• Intravenous (IV) Infusion: The medicine is delivered directly into a vein^1,7. This is a common way of giving several immunotherapy medicines.
• Subcutaneous Injections: Some immunotherapy medicines can be given as an injection into the tissue just beneath the skin. This method may be used for certain kidney cancers⁸.
• Oral Treatment: Some immunotherapy medicines are available as tablets or capsules that are swallowed¹. Certain oral immune-based treatments, such as lenalidomide or pomalidomide,may be used in multiple myeloma⁹.
• Topical Treatment: Some immune-based treatments are applied directly to the skin as a cream for early skin cancers.
• Intravesical Treatment: Certain immunotherapies can be placed directly into the bladder through a catheter for bladder cancer¹.

Note: The choice of immunotherapy depends on the type, stage, and specific features of the cancer, as well as individual patient factors. The dose, timing, and number of treatment sessions also vary by immunotherapy and the individual’s cancer. Tests such as PD-L1 may help doctors decide whether certain treatments are suitable. The treating doctor will decide the most suitable method and schedule.      

Benefits of Immunotherapy

Immunotherapy cancer treatment can offer some benefits, although its effects vary depending on the cancer and individual condition. Some potential benefits include:

• Helps the Immune System Fight Cancer: Immunotherapy can help the body’s natural defence system recognise and attack cancer cells¹.
• May Provide Longer-Lasting Effects: According to some studies, the immune response against cancer continues even after treatment, which led to a lasting response. However, this may not occur in everyone and does not necessarily prevent the cancer from coming back.
• More Targeted Approach: Some immunotherapies are designed to recognise specific features of cancer cells. This may help the immune system focus its response on cancer cells, although nearby healthy cells can sometimes be affected.
• Useful for Many Types of Cancer: Immunotherapy has become a treatment option for several cancers, including melanoma, lung, kidney, bladder, and head and neck cancers, as well as some blood cancers.
• Fewer Side Effects: Although immunotherapy causes side effects, they are fewer compared to other approaches such as chemotherapy and radiation therapy¹⁰.
• May Help Extend Survival: For some people with advanced cancer, immunotherapy may help slow the disease and may contribute to longer survival. However, benefit varies depending on the type of cancer and how the person responds to treatment.
• Works as a Combination Therapy: Depending on the cancer, immunotherapy may be given alone or alongside treatments such as chemotherapy, radiation therapy, and targeted therapy. In some cases, they may be given before or after surgery as part of the overall cancer treatment¹¹.
• Can Be Tailored to Certain Cancer Features: Some immunotherapies are more suitable when a tumour has specific features or biomarkers that suggest it may respond to the treatment³.

Note: The benefits of immunotherapy can vary from person to person. It may not be suitable or effective for every type or stage of cancer. A doctor will consider the type and stage of cancer, tumour characteristics, overall health, and other factors before recommending immunotherapy.

Side Effects and Risks

Because immunotherapy changes immune activity, the immune system can sometimes affect healthy tissues as well as cancer cells. Cancer immunotherapy side effects vary depending on the treatment and the individual. They can occur during treatment and, in some cases, even after treatment has ended.

Possible side effects include:

• Nausea or vomiting
• Fever or chills
• Weakness, fatigue, or dizziness
• Headaches
• Breathing difficulties
• Allergic reactions at the injection site (pain, swelling, soreness, itchiness, rashes, or redness)¹²

Adverse Effects or Risks

While many side effects may be mild, immunotherapy can sometimes cause more serious reactions that require prompt medical attention. Those include the following:

• Lung inflammation/ pneumonitis
• Liver inflammation/ hepatitis
• Endocrine issues, such as thyroid problems or adrenal insufficiency (low adrenal hormone levels)
• Inflammation of the large intestine (colitis)
• Infections
• Mood changes/ difficulty concentrating
• Heart-related issues
• Cytokine release syndrome (CRS) (an immune condition that causes high temperature, breathing difficulty or blood pressure changes)
• Hemophagocytic lymphohistiocytosis (uncontrolled immune system activation which necessitates immediate medical care)
• Myocarditis (inflammation of the heart muscle), encephalitis (inflammation of the brain), or myasthenia-like syndromes (conditions that cause muscle weakness similar to myasthenia gravis, a neuromuscular disease) (rare)¹³

Note: Patients should not ignore new or unusual symptoms during or after immunotherapy. Promptly informing the cancer care team can help doctors identify and manage treatment-related problems.

Who Can Get Immunotherapy?

Not every person with cancer can receive immunotherapy. Doctors consider the type and stage of cancer, specific cancer features, certain biomarkers, how advanced the disease is, and the person’s overall health when deciding whether immunotherapy may be appropriate. The following are some cases where the doctor usually suggests immunotherapy for cancer:

• Approved cancer types, such as lung, kidney, or bladder cancer
• Diagnosed cancer with certain tumour markers, such as PD-L1, dMMR, or MSI-high
• Advanced stages of certain cancers or cancers that have metastasised
• Cancer that has returned⁴
• Healthy enough to receive the treatment

Also Read: ESR Level in Cancer Patients: Normal Range, Causes, Diagnosis & Treatment

When to Consult a Doctor?

Inform your cancer care team of any new, unusual, or worsening symptoms during or after immunotherapy, even if they appear mild. Some side effects may develop several weeks or months after treatment begins and can sometimes occur even after treatment has finished.

Seek medical help promptly if you experience severe diarrhoea, ongoing fever, a new or worsening cough, difficulty breathing, chest pain, severe weakness, unusual skin changes, confusion, or any sudden change in your health while receiving or after receiving the treatment¹³. Informing your doctor early can help them assess the problem and provide appropriate treatment before it becomes more serious.         

Conclusion

Immunotherapy has become an important treatment option for some people with cancer. It works by helping the body’s immune system recognise and fight cancer cells in different ways. However, its benefits and possible side effects can vary depending on the cancer and the individual.

Understanding the treatment and its possible benefits and risks, and discussing suitable options with a doctor, can help patients make informed decisions about their cancer care.

Frequently Asked Questions (FAQs)

References

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2. Immunotherapy: What you need to know. Harvard Health. 2019. Available from: https://www.health.harvard.edu/blog/immunotherapy-what-you-need-to-know-2019012215818

3. Types of cancer immunotherapy. Cancer Research Institute. Available from: https://www.cancerresearch.org/immunotherapy-by-treatment-types

4. Immunotherapy for your cancer type. Cancer Research Institute. Available from: https://www.cancerresearch.org/immunotherapy-by-cancer-type

5. Immunotherapy for ovarian cancer. Cancer Research Institute. Available from: https://www.cancerresearch.org/immunotherapy-by-cancer-type/ovarian-cancer

6. Pessach I, Nagler A. Leukapheresis for CAR-T cell production and therapy. Transfus Apher Sci. 2023;62(6):103828. doi:10.1016/j.transci.2023.103828. Available from: https://www.sciencedirect.com/science/article/abs/pii/S1473050223002434

7. Cancer immunotherapy. MedlinePlus. 2025. Available from: https://medlineplus.gov/cancerimmunotherapy.html

8. George S, Bourlon MT, Chacon MR, et al. Nivolumab injections could make treatment easier for more people with cancer. JCO. 2024;42(4_suppl):LBA360-LBA360. doi:10.1200/JCO.2024.42.4_suppl.LBA360. Available from: https://flasco.org/wp-content/uploads/18028492-FLASCO-Encore-Poster-36x48inch-v5.pdf

9.  Revlimid (Lenalidomide). International Myeloma Foundation. 2026. Available from: https://www.myeloma.org/revlimid-lenalidomide

10. Saxena T, Zaman S, Dhanda H, et al. Immunotherapy for cancer: Current advances and future directions. Int J Mol Sci. 2026;27(16):7216. doi:10.3390/ijms27167216. Available from: https://www.mdpi.com/1422-0067/27/16/7216

11. Immunotherapy for cancer: How it works, benefits and what’s next. American Institute for Cancer Research. Available from: https://www.aicr.org/resources/blog/immunotherapy-for-cancer-how-it-works-benefits-and-whats-next/

12. Immunotherapy side effects. NCI. 2023. Available from: https://www.cancer.gov/about-cancer/treatment/types/immunotherapy/side-effects

13. Immunotherapy side effects. Cancer Research Institute. Available from: https://www.cancerresearch.org/immunotherapy-side-effects

14. Park M, Suh S, Kincaid C, Yale K, Atanaskova Mesinkovska N. Alopecia as an adverse event of immune checkpoint inhibitor therapies: Clinical evidence and outcomes. J Drugs Dermatol. 2025;24(3):255-260. doi:10.36849/JDD.7828. Available from: https://pubmed.ncbi.nlm.nih.gov/40043266/

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