Medically Verified By: Dr. Kapil Goyal
Targeted Therapy vs Immunotherapy: What's the Difference and Which Cancer Treatment Is Right for You?
For many years, the commonly used treatment modalities for cancer were surgery, chemotherapy and radiation therapy. While these continue to remain important in cancer care, now we also have more advanced treatments that are more specific in the way they act. Two such approaches are 'targeted therapy' and 'immunotherapy'. Many patients hear these terms during consultation but aren't quite sure about the differences. While both are advanced cancer treatments and may be used in several types of cancer, they work in very different ways. Today, we'll take a closer look at both of these therapies, while highlighting the key differences.
In this article, Dr Kapil Goyal, DM (Medical Oncology, AIIMS), MD (Medicine), MBBS, Consultant Medical Oncology, helps us better understand targeted therapy.
Targeted therapy is a form of cancer treatment that focuses on specific changes within cancer cells. These changes may involve genes, proteins or signalling pathways that help cancer cells grow, multiply, repair themselves, or spread. Unlike chemotherapy, which mainly affects rapidly dividing cells, targeted therapy is designed to interfere with particular cancer-driving mechanisms. For example, if a tumour has a specific mutation that is helping it grow, a targeted drug may be used to block that mutation or pathway.
This is why biomarker testing or molecular testing is often important before starting targeted therapy. A sample of the tumour, and sometimes blood, may be tested to look for specific mutations or markers. If the relevant target is present, the patient may benefit from a drug designed for that target. If the target is absent, that same drug may not work.
Targeted therapy is commonly used in several cancers, including certain types of lung cancer, breast cancer, colorectal cancer, kidney cancer, gastrointestinal stromal tumours, blood cancers and some other solid tumours. It may be used alone or in combination with chemotherapy, immunotherapy, hormone therapy or radiation, depending on the disease.
Immunotherapy works differently. Instead of directly attacking a cancer-driving mutation, it helps the body's own immune system recognise and attack cancer cells.
Normally, the immune system identifies and destroys abnormal cells. However, cancer cells can sometimes hide from the immune system or switch off immune responses. Some immunotherapy medicines, such as immune checkpoint inhibitors, help release these "brakes" so that immune cells can detect and fight cancer more effectively.
Immunotherapy has changed the treatment landscape for several cancers, including melanoma, lung cancer, kidney cancer, bladder cancer, head and neck cancers, certain gastrointestinal cancers, and some lymphomas. However, it does not work for every patient or every cancer type. Its success depends on tumour biology, immune activity, biomarkers and overall patient condition.
In some patients, immunotherapy may produce long-lasting responses. In others, the cancer may not respond, or the benefit may be limited. This is why careful selection and monitoring are essential.
The simplest way to understand the difference is this: targeted therapy acts mainly on specific cancer cell pathways, while immunotherapy works by helping the immune system recognise and attack cancer cells. Here are the key differences:
Point of Difference Targeted Therapy Immunotherapy
Main action Blocks specific mutations, proteins or growth signals that help cancer cells grow and spread. Helps activate or strengthen the immune system's ability to identify and fight cancer cells.
What it targets Specific changes within the cancer cell or tumour pathway. The immune response against cancer, including immune checkpoints or escape mechanisms.
Need for testing Often requires molecular or genetic testing to confirm whether a suitable target is present. May require biomarker testing such as PD-L1, MSI-H, dMMR or tumour mutational burden in selected cancers.
Speed of response May produce quicker tumour shrinkage when the right target is present. May take longer to show response, but some patients can experience long-lasting benefits.
Use in cancer care Commonly used in selected lung, breast, colorectal, kidney, blood and other cancers with targetable changes. Used in selected cancers such as lung cancer, melanoma, kidney cancer, bladder cancer, head and neck cancers and some lymphomas.
Resistance Cancer cells may develop alternate pathways and stop responding over time. Resistance can also occur, often due to complex interactions between cancer cells and the immune system.
Common side effects May include rash, diarrhoea, high blood pressure, liver changes, mouth ulcers, fatigue or bleeding risk, depending on the drug. May cause immune-related inflammation in organs such as the skin, lungs, liver, thyroid, intestines or kidneys.
Treatment approach Often chosen when a clear molecular target is found. Often chosen when the tumour and immune markers suggest the patient may benefit.
It is important not to think of modern treatments as simply "better" or "worse" than chemotherapy. Each treatment has a role. Chemotherapy remains highly effective in many cancers and is often used with targeted therapy or immunotherapy. The best treatment depends on the cancer type, stage, molecular profile, patient's fitness, prior treatment, symptoms, urgency of disease control and treatment goals. For example, a patient with a targetable mutation may benefit significantly from targeted therapy. Another patient with a tumour that shows immune-sensitive features may be considered for immunotherapy. In some cases, a combination approach may be recommended.
Myth 1: Targeted therapy has no side effects.
It may be more specific than chemotherapy, but it can still cause side effects that require monitoring.
Myth 2: Immunotherapy works for all cancers.
Immunotherapy has shown impressive results in some cancers, but it is not suitable or effective for every patient.
Myth 3: If one modern therapy fails, there are no options left.
Cancer treatment often has multiple lines of therapy. A change in treatment may be possible based on response, resistance pattern and patient condition.
Myth 4: Molecular testing is optional in all cases.
For many cancers, molecular testing is now an important part of treatment planning because it can identify therapies that may work better for selected patients.
Questions Patients Should Ask Their Doctor
Patients should feel comfortable asking: Do I need biomarker or molecular testing? Is there a targetable mutation in my cancer? Am I eligible for immunotherapy? What benefits can I realistically expect? What side effects should I watch for? How will we know if the treatment is working?
These questions help create a clearer treatment roadmap and reduce confusion.
Targeted therapy and immunotherapy are two important pillars of modern cancer treatment, but they are not the same. Targeted therapy aims at specific cancer cell changes, while immunotherapy helps the immune system fight cancer. Both require careful patient selection, scientific testing, close monitoring and realistic counselling. For patients, the most important message is that cancer treatment is becoming more personalised. The right treatment is not chosen only by the name of the cancer, but also by its stage, biology, molecular profile and the patient's overall health. A detailed discussion with a medical oncologist can help patients understand which option is appropriate, when it should be used, and how it fits into the larger treatment plan.
