Immunotherapy vs Chemotherapy in Cancer Treatment

Immunotherapy and Chemotherapy in Cancer Treatment

How They Work, Their Advantages, Disadvantages, Challenges and Long-Term Outcomes

By:  lim ju boo - Chinese name:   lin ru wu (林 如 武)

 

On March 1, 2026 I wrote an article together with Professor P. Sage here:

Technical Paper on Immunotherapy for Cancers vs Cancer Vaccines

 

https://scientificlogic.blogspot.com/search?q=immunotherapy

But I  thought that article we wrote together  may be too technical for ordinary readers to understand. So I decided that I should rewrite it here  in a slightly different way with additional information  using very simple language for the lay public, general readers and also for doctors who may not be conversant with molecular immunology.

 

Introduction:

Cancer has long been one of the greatest medical challenges faced by humanity. For decades, the main weapons against cancer were surgery, radiotherapy, and chemotherapy. In recent years, however, a newer form of treatment called immunotherapy has brought fresh hope to many cancer patients around the world.

Some people even describe immunotherapy as a “revolution” in cancer treatment because instead of directly attacking cancer cells with drugs or radiation, it helps the body’s own immune system fight the cancer naturally.

 Some history between the two therapeutic modalities. 

Chemotherapy was established decades before modern immunotherapy became the standard of care. Here is some history between chemotherapy and immunotherapy. 

 Chemotherapy Began in the 1940s: Modern chemotherapy started during World War II when scientists discovered that nitrogen mustard could treat lymphoma. The US FDA approved the first chemotherapeutic drug in 1949. By the 1960s and 1970s, it had become the cornerstone of cancer care.

Immunotherapy’s Long Road (1890s to 2010s): The conceptual framework dates back to 1891 when Dr. William Coley used bacterial toxins to trigger immune system responses against tumors. However, it remained a niche or experimental field for over a century. Modern immunotherapy only went mainstream in 2011 with the FDA approval of the first immune checkpoint inhibitor (Ipilimumab), revolutionizing cancer care.

Immunotherapy is not universally more effective than chemotherapy. Effectiveness is highly specific to the type, stage, and genetic markers of the cancer. 

Here is the pharmacology between the two

Chemotherapy targets all rapidly dividing cells indiscriminately. This kills cancer cells but also heavily damages fast-growing normal cells (such as hair follicles, the gut lining, and bone marrow). This bone marrow suppression severely depletes white blood cells, temporarily weakening the immune system and increasing infection risks.

Immunotherapy does not directly kill cells. Instead, it unmasks or stimulates the body’s own T-cells to recognize and attack the tumor. While it preserves bone marrow function, it carries a completely different risk: it can over-activate the immune system, causing it to attack healthy organs (resulting in autoimmune side effects like colitis, pneumonitis, or skin rashes)

Traditional chemotherapy drugs (like cisplatin, carboplatin, or paclitaxel) are small chemical molecules. Because their patents expired decades ago, cheap generic versions dominate the market worldwide. 

Conversely, modern immunotherapies (like Pembrolizumab) are complex, large-molecule biologics. Because they are relatively recent breakthroughs, they remain heavily protected by patents. 

Furthermore, even when these patents expire, manufacturing the generic equivalents (called biosimilars) requires complex, highly expensive live cell cultures, meaning prices drop much more slowly than chemical drugs. This is why is immunotherapy so expensive?

We shall talk more about this price difference between chemotherapy and immunotherapy later. 

What are the advantages and disadvantages of both methods?

 

Understanding the Immune System

Before understanding immunotherapy, we must first understand the immune system.

The immune system is the body’s natural defense army against infections and abnormal cells. It consists of many types of cells, organs, proteins, and chemical messengers working together to protect the body.

Among the most important immune cells are:

1. White Blood Cells

These are the “soldiers” of the body that fight infections and abnormal cells.

2. T-Cells

(T-cells are special white blood cells that recognize and destroy infected or abnormal cells, including cancer cells.)

3. B-Cells

(B-cells produce antibodies — proteins that attach to germs or abnormal cells so they can be destroyed.)

Normally, our immune system can detect and destroy abnormal cells before they become cancerous. Unfortunately, cancer cells are clever. They develop ways to hide from the immune system or “switch off” immune attacks.

Immunotherapy attempts to overcome this problem.

 

What is Immunotherapy?

Immunotherapy is a type of cancer treatment that stimulates or strengthens the body’s own immune system to recognize and destroy cancer cells.

Instead of directly poisoning cancer cells like chemotherapy, immunotherapy helps the body defend itself more effectively.

In simple terms:

1. Chemotherapy attacks the cancer directly.

 

2. Immunotherapy helps the body attack the cancer.

 

What is Chemotherapy?

Chemotherapy uses powerful drugs to kill rapidly dividing cells.

Cancer cells grow and divide very quickly. Chemotherapy targets these fast-growing cells.

Unfortunately, many normal healthy cells in the body also divide rapidly, such as:

1. Hair follicle cells

2. Cells lining the mouth and intestines

3. Bone marrow cells (which produce blood cells)

 

Because chemotherapy damages these healthy cells too, side effects commonly occur.

 

Common Side Effects of Chemotherapy

These include:

1. Hair loss

2. Nausea and vomiting

3. Mouth ulcers

3. Loss of appetite

4. Fatigue

5. Increased risk of infections

6. Anaemia

7. Bleeding problems

1. 

Chemotherapy can sometimes save lives, but it may also weaken the body significantly.

Types of Immunotherapy

There are several forms of immunotherapy.

 

1. Immune Checkpoint Inhibitors

This is one of the most important breakthroughs in modern cancer treatment.

Cancer cells sometimes use certain proteins called checkpoints to stop immune cells from attacking them.

What are “checkpoints”?

Checkpoints are like “brakes” in the immune system.

Normally, these brakes prevent the immune system from becoming overactive and attacking normal tissues.

Cancer cells exploit these brakes to protect themselves.

Immunotherapy drugs called checkpoint inhibitors block these brakes, allowing immune cells to attack cancer more aggressively.

Examples include:

1. Pembrolizumab

2. Nivolumab

3. Ipilimumab

These drugs have shown remarkable success in some cancers such as:

1. Melanoma (skin cancer)

2. Lung cancer

3. Kidney cancer

4. Hodgkin lymphoma

Some patients with advanced cancer have survived for many years after treatment — something rarely seen previously.

2. Monoclonal Antibodies

Monoclonal antibodies are man-made proteins designed to attach to specific targets on cancer cells.

Think of them as “guided missiles.”

Once attached to cancer cells, they help the immune system recognize and destroy those cells.

Examples include:

1. Rituximab

2. Trastuzumab

What is HER2-positive breast cancer?

HER2 is a protein found on some breast cancer cells.

In certain patients, the cancer cells produce excessive HER2 proteins, causing the cancer to grow faster and behave more aggressively.

This is called HER2-positive breast cancer.

Trastuzumab specifically targets HER2 proteins, helping slow or stop the cancer.

 

3. CAR T-Cell Therapy

CAR T-cell therapy is among the most advanced and fascinating forms of immunotherapy.

How does it work?

1. Doctors remove some of the patient’s T-cells from the blood.

2.  In the laboratory, these T-cells are genetically modified to better recognize cancer cells. 

3. The modified cells are multiplied into millions.

4. The new “supercharged” T-cells are infused back into the patient.

These engineered cells can then attack cancer more effectively.

This treatment has shown dramatic success in some blood cancers such as leukemia and lymphoma.

However, it is extremely expensive and technically complex.

 

4. Cancer Vaccines

Cancer vaccines train the immune system to recognize cancer-related proteins.

These vaccines differ from ordinary vaccines.

Traditional vaccines prevent diseases before they occur. Cancer vaccines usually help the body fight cancers that already exist.

Some vaccines may also help prevent certain cancers indirectly.

For example:

1) The HPV vaccine reduces the risk of cervical cancer.

b) The Hepatitis B vaccine reduces the risk of liver cancer.

 

5. Immune System Modulators

These drugs generally strengthen the immune system overall.

Examples include:

  1. Interferons

(Proteins naturally produced by the body to fight viruses and abnormal cells.)

2. Interleukins

(Chemical messengers that help immune cells communicate.)

3. Thalidomide

(A drug that affects immune activity and blood vessel growth in cancers such as multiple myeloma.)

Advantages of Immunotherapy

1. More Targeted Treatment

Immunotherapy often targets cancer cells more specifically than chemotherapy.

This may reduce damage to normal healthy cells.

 2. Long-Term Immune Memory

One remarkable feature is that the immune system may “remember” cancer cells.

This means some patients continue benefiting even after treatment stops.

A few patients achieve very long survival.

3. Fewer Traditional Side Effects

Many patients do not experience severe hair loss, severe nausea, or severe vomiting seen with chemotherapy.

 4. Useful for Advanced Cancers

Some advanced cancers that respond poorly to chemotherapy may respond dramatically to immunotherapy.

 

Disadvantages of Immunotherapy

1. Not All Patients Respond

This is one of the biggest limitations.

Some patients respond extremely well, while others show little or no improvement.

Doctors are still trying to understand why.

2. Immune System Overreaction

Sometimes the activated immune system attacks normal organs.

This may cause:

1. Lung inflammation

2. Liver inflammation

3. Colitis (inflammation of the intestines)

4. Skin rashes

5. Hormonal disorders

 

In severe cases, these reactions can become life-threatening. 

As I promised earlier, we shall now talk about the price  differences in between the older chemotherapy and the more recent immunotherapy. 

Immunotherapy can cost half a million ringgit  for the whole course per patient 

Reasons include:

a) Complex Research and Development

Developing immunotherapy drugs requires years of advanced scientific research, biotechnology, and clinical trials.

b) Scientists in research and development need to be very highly paid - one of the highest professions in the world working on them. They may take many years to study them with many failures in trials and errors, and this is very, very costly. Scientists also need to carry out numerous clinical trials to evaluate their clinical efficacy and safety before allowing doctors to use them. That added to the cost. The pharmaceutical companies that employs them then patent their products and jack up the price. 

 See my detailed explanation here in this link later. 

From Molecule to Medicine: The Hidden Army of Scientists Behind Every New Drug

https://scientificlogic.blogspot.com/search?q=drug+development 

 

c) Genetic Engineering

Treatments like CAR T-cell therapy involve sophisticated genetic manipulation of living cells.

This requires highly specialized laboratories and equipment.

 

d) Personalized Treatment

Some immunotherapies are customized for individual patients, greatly increasing costs.

e) Manufacturing Complexity

Unlike ordinary chemical drugs, many immunotherapy agents are biological products produced from living cells.

Manufacturing them is technically difficult and expensive. Not just that alone. Scientists working in cancer research meet many failures and challenges and they are very, very costly before they can offer a promising drug or a treatment to doctors

 

f) Patent and Commercial Costs

Many immunotherapy drugs are still under patent protection, limiting cheaper generic competition.

 

Advantages of Chemotherapy

1. Works Quickly

Chemotherapy can rapidly shrink tumors.

This is important when cancer is growing aggressively.

 

2. Effective for Many Types of Cancer

Chemotherapy remains highly useful in:

1.  Leukemia

2. Lymphoma

3. Breast cancer

4. Testicular cancer

5. Childhood cancers

 

Some cancers can even be cured with chemotherapy alone.

 

3. More Widely Available

Chemotherapy is available in most hospitals worldwide and is generally cheaper than immunotherapy.

Disadvantages of Chemotherapy

1. Damages Healthy Cells

Because chemotherapy attacks rapidly dividing cells, many normal tissues are affected.

 

2. Severe Side Effects

Patients may become weak, nauseated, anaemic, and vulnerable to infections.

 

3. Drug Resistance

Some cancers eventually become resistant to chemotherapy drugs.

The cancer may return despite treatment.

 

Which Has Better Outcomes?

This is a very important question.

The answer is not simple.

Chemotherapy

Chemotherapy may produce rapid tumor shrinkage and remains lifesaving for many cancers.

However, in some advanced cancers, the benefit may be temporary because the cancer eventually returns.

Immunotherapy

Immunotherapy may not work for everyone, but when it works well, the responses can sometimes be remarkably durable.

Some patients with advanced cancers have survived for many years after immunotherapy.

This is one reason immunotherapy has generated enormous excitement worldwide.

Why Does Immunotherapy Sometimes Produce Better Long-Term Results?

The main reason is immune memory.

Once the immune system learns to recognize cancer cells, it may continue monitoring and suppressing them long after treatment ends.

Chemotherapy usually works only while the drugs are being administered.

 

Can Chemotherapy and Immunotherapy Be Combined?

Yes.

Doctors often combine:

1.  Surgery

2. Radiotherapy

3. Chemotherapy

4. Immunotherapy

Different combinations may improve outcomes depending on the type and stage of cancer.

In some cases, chemotherapy may even help immunotherapy work better by exposing cancer cells more clearly to the immune system.

The Future of Cancer Treatment

Cancer treatment is advancing rapidly.

Scientists are now exploring:

1. Personalized cancer vaccines

2. Gene therapy

3. Combination immunotherapy

4. Artificial intelligence-guided treatments

5. Precision medicine

(Treatment tailored specifically to an individual patient’s genetic profile.)

The future may involve treatments that are more precise, more effective, and less harmful to healthy tissues.

Immunotherapy represents one of the most exciting developments in modern medicine. Instead of merely poisoning cancer cells, it harnesses the extraordinary power of the body’s own immune defenses.

Nevertheless, immunotherapy is not a miracle cure for all cancers. Some patients respond dramatically while others do not. It also carries risks, limitations, and extremely high costs.

Chemotherapy, despite its side effects, still remains one of the most important and lifesaving weapons against cancer.

Rather than viewing chemotherapy and immunotherapy as enemies, modern medicine increasingly sees them as complementary partners working together against cancer.

The ultimate hope of medical science is not only to prolong life, but also to improve the quality of life while reducing suffering for cancer patients around the world. I hope this simplified article helps just to share freely, and that I have not left out anything as I have tried my level best. 

- jb lim