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Difference between Chemotherapy and Immunotherapy: Which Therapy is Better for You?

Difference between Chemotherapy and Immunotherapy: Which Therapy is Better for You?




Chemotherapy and immunotherapy are commonly used treatment methods for different types of cancers. Both therapies act differently to control the growth and spread of cancer cells.

This article covers the major differences between chemotherapy and immunotherapy. We will cover aspects such as their effectiveness, side effects, the type of cancers they act upon, and the expenses involved.




Chemotherapy is a chemical treatment that uses drugs and directly affects cancer cells. The medications in chemotherapy decrease the cell division of cancer cells. Hence, it helps control cancer growth and prevent the spread of cancer cells to other body parts.

Immunotherapy acts indirectly on cancer cells. Some cancer cells can escape the immune system due to genetic modifications. Due to these changes, the cancer cells can replicate uncontrollably without getting attacked by the immune system.

But immunotherapy for cancer helps to improve the immune system.

The immune system can recognize cancer cells and synthesize specific T cells. The T cells are part of the immune system that protects our body from foreign particles. They can play a significant role in the action of the immune system against tumours.


Differences between Chemotherapy and Immunotherapy


Immunotherapy vs chemotherapy depends on various factors.


Duration of Action


Chemotherapy can act on cancer cells as long as it is present in the body. It directly affects the cancer cells and starts to work immediately after administration.

On the other hand, immunotherapy stimulates the immune system, taking longer to begin its action. It remains effective even after stopping the active treatment.




The effectiveness of chemotherapy lasts as long as the patient continues the drugs. At the same time, immunotherapy is effective even after stopping the treatment.

Immunotherapy increases the immune memory against cancer cells and prevents recurrence. This memory makes immunotherapy more durable and practical in the long term.

Suppose the patient undergoes immunotherapy and chemotherapy in tandem. In that case, the overall outcome is more favourable and stays for a longer duration.


Side Effects


Chemotherapy attacks the cancer cells that divide in an uncontrolled manner. But it also affects the rapidly dividing body cells like hair, skin, blood cells, and intestinal cells. It consequently leads to side effects like hair loss, nausea, skin infections, sores, and dry skin.

Side effects associated with immunotherapy occur due to over activation of the immune system. It includes nausea, flu, fever, dizziness, muscle aches, joint pain, and reaction at the injection site.


Cancer Type


Doctors prefer using chemotherapy to shrink cancer before surgery. It also helps prevent the recurrence of most cancer cells. It is also helpful to slow down the progress of last stage cancers.

Immunotherapy works by enhancing the immune system and is beneficial for all cancers. Medical professionals explicitly use it in cancers that are resistant to chemotherapy.


Mode of Administration


One can administer drugs used in immunotherapy through an intravenous route. Medical professionals inject immunotherapy drugs under the skin or muscles in a few cases. In cases of skin cancers, doctors use a topical cream to deliver immunotherapy medication to the skin. For bladder cancer, doctors inject the immunotherapy directly into the bladder with the help of a catheter.

Chemotherapy can be given directly into the bloodstream using catheter or IV infusion pumps. Chemotherapy drugs can also be delivered to the spinal cord using a catheter. It can reach directly into the surrounding fluid brain and spinal cord.

One can also inject the chemo drugs into the main artery that supplies the tumour site.

In some instances, the tumour involves organs in enclosed areas of the body like the chest, abdomen, or bladder. The medical technician delivers the chemotherapy drug directly into these cavities using a catheter in such situations.

In addition, chemo drugs can also be delivered to the muscles or injected directly into the tumour.


Type of Drugs


Chemotherapy includes drugs like alkylating agents that act on the DNA of cells, kill the cancer cells, and prevent their multiplication.

Alkylating agents can affect the bone marrow, hampering blood cells' formation if used for a prolonged duration at higher doses. Antimetabolites are drugs that interact with the DNA and RNA of cells preventing their multiplication.

Antitumor antibiotics are extracted from micro-organisms. These drugs affect DNA synthesis and also break down the DNA strands.

Mitotic and Topoisomerase inhibitors are chemotherapy drugs arresting cell division by damaging the enzymes needed for cellular proliferation. At higher doses, mitotic inhibitors can cause nerve damage.

Immunotherapy drugs include monoclonal antibodies that combine with the surface protein of cancer cells and destroy cancer.

Immunotherapy also employs cancer vaccines. These vaccinations are produced using dead cancer cells or their proteins and help activate the immune system against cancer. Immune system modulators like interleukins and interferons help to boost the immune system to fight against tumour cells.

In T cell transfer therapy, the cells are extracted from the patient's body. They are modified and grown in the laboratory. These cells are then transferred back into the body to enhance the overall immune response. This process can take 2-8 weeks.




The overall cost of treatment depends on various factors like the type of cancer, stage of cancer, and type of treatment. Immunotherapy for cancer is generally given for longer durations, costing more than chemotherapy.


Biochemical Markers Affecting Treatment Decision:


Biochemical markers are commonly used to choose the treatment modality that will be effective for particular cancer. The biochemical markers are biochemical compounds like hormones, enzymes, proteins, antigens, or antibodies produced or altered during the initiation or progression of the disease.

The biochemical markers associated with different types of cancers include:

  • PL-1: This protein in tumour cells prevents the immune system's attack on these cells. More PL-1 protein indicates that immunotherapy will be more effective.
  • Microsatellite Instability-High: This biomarker reflects the inability of the body to repair any damage in DNA. It leads to the formation of abnormal proteins and abnormal cell division. Immunotherapy is the only effective treatment for these cancers.
  • Tumour Mutation Burden: This test analyses the density of tumour mutations with the help of genome sequence. These mutations make immunotherapy the preferable treatment option.




Immunotherapy and chemotherapy are two different drug therapies used to treat different cancers. While chemotherapy acts directly on cancer cells, immunotherapy works by boosting the immune system to fight against cancer cells. Always consult the oncologist and discuss the best treatment options available for you.

If you have been diagnosed with cancer and want the best treatment integrated with advanced technology, book an appointment with oncologists in Medanta.

Dr. Harshvardhan Atreya
Cancer Care
Meet The Doctor
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