Chemotherapy vs Immunotherapy: What Every Cancer Patient should Know

Cancer treatment has changed significantly over the past two decades. While chemotherapy has long been one of the most widely used cancer treatments, newer approaches such as immunotherapy are now offering additional options for many patients. Both treatments are used to fight cancer, but they work in very different ways, are recommended for different situations, and can affect the body differently.

For many patients and families, understanding the difference between chemotherapy and immunotherapy can be confusing, especially at the time of diagnosis. Questions about effectiveness, side effects, treatment duration, and suitability are quite common. In this article, we’ll explain how chemotherapy and immunotherapy work, where they differ, their benefits and limitations, and what cancer patients and their families should know before starting treatment.

What is Chemotherapy?

Chemotherapy refers to the use of cytotoxic drugs that interfere with the ability of cells to divide and multiply. Cancer cells grow rapidly and uncontrollably, and chemotherapy targets this characteristic by disrupting the cellular processes required for replication.

How Chemotherapy Works

Most chemotherapy drugs work by damaging DNA within cells, interrupting the cell cycle, or blocking the proteins needed for cell division. Because cancer cells divide more frequently than most healthy cells, they are more vulnerable to these drugs. However, some normal cells that naturally grow and divide quickly, such as those in the hair follicles, gastrointestinal lining, and bone marrow, can also be affected. This is why chemotherapy is commonly associated with side effects such as hair loss, nausea, fatigue, and reduced blood cell counts.

Chemotherapy is considered a systemic treatment, meaning it travels throughout the body through the bloodstream. This allows it to reach cancer cells wherever they may be present, including microscopic disease that may not yet be visible on scans or imaging.

Types of Chemotherapy

Chemotherapy is not a single medicine but a broad category of drugs with different mechanisms of action. Different chemotherapy agents are selected depending on the type, stage of disease, and treatment goals.

The main categories include some agents like:-

• Alkylating agents
• Antimetabolites
• Taxanes
• Anthracyclines
• Topoisomerase inhibitors

When Is Chemotherapy Used?

Chemotherapy is used in several different clinical settings depending on the cancer type and stage.

• Before surgery (neoadjuvant chemotherapy): To shrink a tumour and make surgery more effective or less extensive.
• After surgery (adjuvant chemotherapy): To destroy microscopic cancer cells that may remain after tumour removal and reduce the risk of recurrence.
• As primary treatment: For cancers that cannot be removed surgically or are highly responsive to chemotherapy.
• For advanced or metastatic cancer: To slow disease progression, control symptoms, and improve quality of life when cure may not be possible.

What Is Immunotherapy?

Immunotherapy works very differently from chemotherapy. Instead of attacking cancer cells directly with cytotoxic drugs, immunotherapy helps the body’s own immune system recognise and fight cancer more effectively.

How Immunotherapy Works

The immune system is designed to identify and destroy abnormal cells. However, cancer cells can develop ways to escape immune detection. They may hide from immune cells, suppress immune responses, or create conditions that prevent the immune system from functioning properly. Immunotherapy is designed to overcome these defence mechanisms.

Different forms of immunotherapy work in different ways. Some block the signals cancer cells use to switch off immune cells, while others help the immune system recognise tumour cells more clearly. Certain therapies genetically modify immune cells to improve their ability to target cancer, while others stimulate a broader immune response against the tumour.

One of the most important features of immunotherapy is its potential for long-term disease control. In some patients, the immune system develops a lasting memory of the cancer cells it has been trained to recognise, allowing it to continue suppressing the disease even after treatment ends.

Types of Immunotherapy

Several types of immunotherapy are now used in modern cancer care, depending on the cancer type and the patient’s molecular profile.

• Immune checkpoint inhibitors: These are the most widely used immunotherapy drugs. They block proteins such as PD-1, PD-L1, or CTLA-4 that cancer cells use to suppress immune activity. Examples include pembrolizumab, nivolumab, atezolizumab, and ipilimumab.
• CAR-T cell therapy: In this treatment, a patient’s own T-cells are collected, genetically modified to recognise cancer cells, and then returned to the body. CAR-T therapy has shown significant success in certain blood cancers.
• Cancer vaccines: These vaccines help train the immune system to recognise tumour-specific antigens, including mutations unique to an individual patient’s cancer.
• Cytokine therapy: This approach uses immune signalling proteins such as interleukins and interferons to stimulate immune cell activity against cancer cells.

When is Immunotherapy Used?

Immunotherapy may be used as a primary treatment, alongside chemotherapy, or after other treatments have stopped working as a maintenance therapy. Its effectiveness depends heavily on the type of cancer and the tumour’s molecular characteristics.

Doctors often evaluate biomarkers such as PD-L1 expression, microsatellite instability (MSI) status, and tumour mutational burden (TMB) before recommending immunotherapy. These markers help identify patients who are more likely to benefit from treatment.

Immunotherapy is now a standard treatment option for several cancers, including lung cancer, melanoma, head and neck cancers, bladder cancer, kidney cancer, certain colorectal cancers, triple-negative breast cancer, and cervical cancer.

Chemotherapy vs Immunotherapy: How They Differ

Although chemotherapy and immunotherapy are both used to treat cancer, they work through entirely different mechanisms and are recommended for different clinical reasons. The choice between them depends on the type of cancer, stage of disease, molecular characteristics of the tumour, treatment goals, and the patient’s overall health.

Understanding how these treatments differ across the areas that matter most to patients can make treatment discussions clearer and more meaningful. It also explains why oncologists may recommend one approach over the other, or in many cases, use both together as part of a personalised cancer treatment plan.

Side Effects: Chemotherapy vs Immunotherapy

Both chemotherapy and immunotherapy can cause side effects, but they do so through very different biological mechanisms. Understanding these differences helps patients recognise symptoms early and seek timely medical attention when needed.

Chemotherapy Side Effects

Chemotherapy side effects occur because the drugs affect not only cancer cells but also healthy cells that naturally divide quickly, such as those in the hair follicles, bone marrow, mouth, and digestive tract.

Common chemotherapy side effects include:

• Nausea and vomiting
• Hair loss (alopecia
• Fatigue
• Immune suppression (neutropenia)
• Mucositis or mouth ulcer
• Peripheral neuropathy
• Anaemia

Most chemotherapy-related side effects improve after treatment ends, although some effects, particularly neuropathy, may persist for longer in certain patients.

Immunotherapy Side Effects>

Immunotherapy side effects are different because they result from increased immune activity. In some cases, the immune system may begin attacking healthy tissues and organs. These are known as immune-related adverse events (irAEs).

Common and clinically important immunotherapy side effects include:

• Skin reactions
• Colitis
• Pneumonitis
• Hepatitis
• Endocrine dysfunction
• Inflammatory arthritis

A key feature of immunotherapy side effects is that they can affect almost any organ system and may develop weeks or even months after treatment has started. Their management is also different from chemotherapy-related side effects and may involve immunosuppressive medications such as corticosteroids rather than supportive care alone.

Early reporting of new symptoms is extremely important during immunotherapy treatment.

At RGCIRC: All patients receiving chemotherapy or immunotherapy undergo regular clinical monitoring throughout their treatment journey. Blood tests, imaging, and ongoing clinical assessments help identify side effects early so they can be managed promptly and effectively. The medical oncology and supportive care teams work closely together to help patients continue treatment as safely and comfortably as possible.

Can Chemotherapy and Immunotherapy Be Used Together?

Yes. In many cancers today, combining chemotherapy and immunotherapy has become a standard treatment approach rather than an exception.

The scientific basis for combining these treatments is strong. As chemotherapy destroys cancer cells, those cells release tumour antigens that make the cancer more visible to the immune system. This process can improve the body’s ability to recognise and attack remaining cancer cells. Immunotherapy then helps strengthen that immune response by blocking the mechanisms tumours use to suppress immune activity.

Together, these treatments can work synergistically, allowing chemotherapy to expose the tumour and immunotherapy to enhance the immune system’s ability to respond.

Combination treatment can lead to higher rates of side effects compared to using either treatment alone, particularly moderate to severe treatment-related adverse events, But studies have shown that these combinations can significantly improve outcomes in selected patients when carefully monitored and appropriately managed.

Chemotherapy and immunotherapy combinations are now commonly used as first-line treatment in several cancers, including:

• Non-small cell lung cancer
• Triple-negative breast cancer
• Gastric and gastro-oesophageal junction cancers
• Biliary tract cancer
• Cervical cancer

The decision to use combined treatment is always individualised. Oncologists consider several factors, including the cancer type, stage, biomarker profile, overall health, expected treatment benefits, and the patient’s treatment goals before recommending a combined approach.

How Do Oncologists Choose Between the Two?

For most patients, the question is not simply “chemotherapy or immunotherapy.” The real question is which treatment, or combination of treatments, is most appropriate for a specific cancer, at a specific stage, in a specific patient. To answer that, oncologists evaluate several important clinical factors before recommending a treatment plan.

Cancer Type and Stage

The type of cancer and how far it has spread are the starting points of treatment planning.

Chemotherapy remains effective across a very broad range of cancers and disease stages. Immunotherapy, while increasingly important, is currently effective only in selected cancers and in patients whose tumours show certain biological characteristics or biomarkers.

The stage of cancer also influences treatment intensity, treatment combinations, and whether the goal is cure, long-term control, or symptom management.

Molecular and Biomarker Profile

Biomarker testing plays a central role in deciding whether immunotherapy is likely to work.

Tests for markers such as PD-L1 expression, microsatellite instability (MSI), tumour mutational burden (TMB), and specific genetic mutations help oncologists identify patients who may benefit from immunotherapy and select the most appropriate treatment.

At RGCIRC, advanced molecular testing and next-generation sequencing are used for patients with advanced cancers to support more personalised treatment planning.

Patient Health and Fitness

A patient’s overall health is equally important in treatment selection.

Factors such as age, nutritional status, heart function, kidney function, liver function, and existing medical conditions influence which treatments can be given safely. For example:

• Patients with autoimmune diseases may have a higher risk of complications from immunotherapy.
• Patients with reduced kidney or cardiac function may require chemotherapy dose adjustments or alternative regimens.

Performance status, which reflects how well a patient is able to carry out daily activities, is also carefully assessed before treatment begins.

Treatment Goals

The purpose of treatment significantly affects the treatment strategy.

• Curative treatment: Aims to eliminate all detectable cancer and may involve more intensive treatment combinations.
• Palliative treatment: Focuses on slowing disease progression, controlling symptoms, and maintaining quality of life when cure is not possible.

Previous Treatment History

For patients who have already received cancer treatment, oncologists also consider what therapies have been used before and how the cancer responded.

Some immunotherapy drugs are most effective when used as first-line treatment, while others are approved after progression on chemotherapy or targeted therapy. Prior side effects, resistance patterns, and remaining treatment options all influence future treatment decisions.

Why Choose RGCIRC for Cancer Treatment?

RGCIRC is the largest standalone cancer centre in northern India. It requires confidence in the expertise guiding every treatment decision, the technology supporting diagnosis and monitoring, and the multidisciplinary systems that ensure care remains personalised at every stage. We offer:

Medical Oncology Expertise

The Medical Oncology team at RGCIRC has extensive experience in delivering chemotherapy, immunotherapy, targeted therapy, and combination treatment regimens across a wide range of cancers. Treatments are administered in dedicated oncology daycare facilities under the supervision of experienced specialists trained to monitor and manage treatment-related side effects promptly and effectively.

Multidisciplinary Treatment Planning

Patients undergoes evaluation through a multidisciplinary tumour board before treatment begins. Medical oncologists, surgical oncologists, radiation oncologists, radiologists, pathologists, and other specialists collaborate to review the diagnosis, stage, molecular findings, and overall treatment strategy. This ensures that decisions regarding chemotherapy, immunotherapy, or combined treatment are evidence-based and tailored to the patient’s individual clinical profile.

Molecular Testing and Precision Oncology

Advanced cancer treatment increasingly depends on understanding the biology of the tumour itself. RGCIRC established one of India’s earliest dedicated in house molecular laboratories for oncology and offers comprehensive biomarker and next-generation sequencing (NGS) testing.

These tests help identify patients who are most likely to benefit from immunotherapy and support more precise treatment selection.

Accreditation and National Recognition

RGCIRC holds NABH accreditation (5th Edition), NABL accreditation, Green OT certification, and Nursing Excellence certification. The institute has also received several national and international recognitions, including:

• Recognition among the World’s Best Specialised Hospitals by Newsweek (2024 and 2025)
• Ranked No. 1 in North India among single-speciality hospitals by The Times of India (2025)
• Awarded Best Oncology Hospital of the Year 2026 by the IHW Council

Commitment to Accessible Cancer Care

As a not-for-profit institution, RGCIRC remains committed to making advanced cancer care accessible to more patients. Through its Philanthropy Department, financial assistance and subsidised treatment support are provided to eligible patients, helping ensure that access to cancer treatment is guided by clinical need rather than financial limitations.

Book a Consultation at RGCIRC

If you or a loved one has been diagnosed with cancer and would like to understand which treatment approach may be most suitable, the Medical Oncology team at RGCIRC is available for consultation. Whether you are beginning treatment or seeking a second opinion, our specialists provide evidence-based guidance and personalised cancer care tailored to your diagnosis and clinical needs.

To book a consultation with a specialist at RGCIRC, simply Call +91-11-4702 2222 (Rohini) / +91-11-4582 2222 (Niti Bagh, South Delhi) Book online at care.rgcirc.org | Download the RGCI Care app on iOS and Android.

OPD Hours: Monday to Saturday, 9:00 AM to 5:00 PM | Emergency Services: 24×7 at both campuses

Frequently Asked Questions (FAQs)

Is immunotherapy better than chemotherapy?

Neither treatment is universally better. Chemotherapy works across a broad range of cancers, while immunotherapy is most effective in cancers with specific biomarkers. In many cases, both treatments are used together for better outcomes.

Can chemotherapy and immunotherapy be used together?

Yes. Combining chemotherapy and immunotherapy is now a standard treatment approach for several cancers, including lung, triple-negative breast, gastric, and biliary tract cancers. The combination can improve outcomes in selected patients.

How do doctors choose the right treatment?

Oncologists consider the cancer type, stage, biomarker profile, overall health, organ function, previous treatments, and treatment goals before recommending chemotherapy, immunotherapy, or both.

Is immunotherapy suitable for all patients?

No. Immunotherapy works best in cancers with specific biomarkers such as PD-L1 expression or MSI-H status. Patients with autoimmune conditions may excluded from this.

In which stage of cancer is chemotherapy used?

Chemotherapy may be used in early-stage, locally advanced, and metastatic cancers. It can be given before surgery, after surgery, or as the main treatment depending on the cancer type and treatment goals.

How long does immunotherapy treatment last?

Treatment duration varies depending on the stage, cancer type, drug used, and patient response. Some patients receive fixed treatment cycles, while others continue treatment as long as it remains effective and well tolerated.

Is taking chemotherapy painful?

Chemotherapy infusions themselves are usually not painful. However, side effects such as nausea, fatigue, mouth sores, or neuropathy can cause discomfort. Modern supportive care helps manage these side effects more effectively.

Can cancer be cured with immunotherapy?

In some cancers, immunotherapy has produced long-term remission and durable disease control. However, outcomes vary depending on the cancer type, stage, and individual response to treatment.

Can cancer be cured with chemotherapy?

Yes, chemotherapy can be curative in early cancers stages. In advanced cancers, it is more commonly used to control disease and extend survival, quality of life of the pateint

How many rounds of chemotherapy are usually needed?

Most chemotherapy regimens involve around four to eight cycles, although this varies depending on the cancer type, treatment plan, and patient response. Your oncologist will review progress throughout treatment and adjust the plan if needed.