Who Is a Good Candidate for Immunotherapy?

For some patients, it can produce meaningful and sometimes long-lasting responses by helping the immune system mount a more effective response against cancer cells.

But being diagnosed with a cancer that can respond to immunotherapy does not automatically mean the treatment is suitable. The decision depends on the type and stage of cancer, tumour biology, previous treatments, general health and the potential risks of activating the immune system.

What Makes Someone Suitable for Immunotherapy?

There is no single test that determines whether someone is a good candidate.

The first question is whether immunotherapy has an established role for the particular cancer and treatment setting. It may be used for certain cancers before surgery, after surgery to reduce the risk of recurrence, or for locally advanced or metastatic disease.

The aim also varies. Immunotherapy may be used on its own or alongside other cancer treatments, depending on the diagnosis.

This is why decisions about immunotherapy treatment need to be based on the individual cancer rather than simply whether a patient is generally fit enough to receive treatment.

Several factors are considered together, and no single one necessarily provides the entire answer.

The Type and Stage of Cancer Come First

Immunotherapy is not effective against every type of cancer.

Checkpoint inhibitors, one of the most widely used forms of immunotherapy, have established roles in cancers including melanoma and several types of lung cancer. Even within these cancers, however, the way they are used can differ considerably.

Someone with an earlier-stage cancer may receive immunotherapy before or after surgery in a particular treatment pathway. Another patient with advanced disease may receive it as their main systemic treatment, either alone or in combination with another therapy.

For example, immunotherapy for melanoma can be used in selected patients with higher-risk or advanced disease, while surgery remains central to the treatment of many earlier melanomas.

The diagnosis therefore needs to be considered in its full clinical context.

Biomarkers Can Help Guide the Decision

Modern cancer treatment increasingly relies on information about the tumour itself.

One biomarker commonly discussed in lung cancer is PD-L1. This protein can be measured in tumour tissue and may help indicate whether certain checkpoint inhibitors are appropriate.

In some forms of advanced or metastatic non-small cell lung cancer, higher PD-L1 expression can support the use of immunotherapy alone, although the relevant threshold and treatment options depend on the specific clinical setting.

Immunotherapy can also be used in combination with chemotherapy in some situations where PD-L1 expression is lower. A low PD-L1 result therefore does not automatically mean that immunotherapy cannot be used. Equally, a high result does not guarantee that treatment will work.

Other molecular findings matter too. Molecular testing in non-small cell lung cancer may identify alterations such as EGFR or ALK that can substantially change the treatment pathway. In advanced disease, an appropriate targeted therapy may take priority over immunotherapy for certain actionable alterations, while molecular findings can also influence eligibility for immunotherapy in earlier-stage treatment pathways.

This is why biomarker results need to be interpreted together rather than in isolation.

General Health Matters, but Fitness Is Not the Whole Story

Before immunotherapy is recommended, the oncology team will consider whether the patient is well enough for treatment and whether there are medical conditions that could make it less safe.

This assessment may include symptoms, day-to-day functioning, previous cancer treatments and the health of organs such as the liver, kidneys and lungs. Blood tests are commonly performed before and during treatment.

Age alone does not determine whether someone can receive immunotherapy.

An older patient who is otherwise reasonably fit may still be considered for treatment, while a younger person with particular medical problems may require much more careful assessment.

The question is therefore not simply, "Am I healthy enough?" It is whether the likely benefit of treatment is reasonable when weighed against the potential risks for that individual.

Why Autoimmune Conditions Need Careful Consideration

Immunotherapy works by increasing or restoring immune activity against cancer. The same mechanism that makes treatment effective can also cause the immune system to attack healthy tissues.

These are known as immune-related adverse effects.

They can affect different parts of the body, including the skin, bowel, liver, lungs and hormone-producing glands. Many immune-related side effects can be managed when recognised and treated promptly, but some can become serious or, rarely, life-threatening.

For this reason, a pre-existing autoimmune condition such as rheumatoid arthritis, inflammatory bowel disease or lupus may make treatment decisions more complicated.

Having an autoimmune condition does not necessarily mean immunotherapy is impossible. The type of condition, how active it is, the treatment needed to control it and the expected benefit from immunotherapy all need to be considered carefully.

Organ Transplants Can Change the Risk

A history of organ transplantation is particularly important when considering checkpoint inhibitor immunotherapy.

Someone who has received a transplanted organ usually takes medication that suppresses the immune system to reduce the risk of rejection. Because checkpoint inhibitors stimulate immune activity, treatment may create a risk that the immune system attacks the transplanted organ.

This does not lend itself to a simple rule that applies to every patient. The type of transplant, cancer, available alternatives and potential consequences of rejection all matter.

Cases of this kind require particularly careful specialist assessment and discussion of the balance between potential benefit and risk.

Previous Treatment Can Influence What Comes Next

Immunotherapy may be considered at different points in the cancer pathway, so what a patient has already received can affect whether it is appropriate.

Previous surgery, chemotherapy, radiotherapy, targeted therapy or immunotherapy can all influence the next decision. The cancer's response to previous treatment and any significant side effects also matter.

For patients with advanced non-small cell lung cancer, for example, the treatment pathway can depend heavily on molecular results and PD-L1 expression. Metastatic non-small cell lung cancer treatment may involve immunotherapy alone, immunotherapy combined with chemotherapy, targeted therapy or another approach depending on the biology of the tumour.

The best candidate for immunotherapy is therefore not necessarily someone who has exhausted every other treatment. In several cancers, immunotherapy now appears much earlier in the treatment pathway.

Being Eligible Does Not Mean Immunotherapy Will Definitely Work

This is an important distinction.

Biomarkers and clinical characteristics help identify patients who may be more likely to benefit, but they cannot predict an individual's response with certainty.

Some cancers respond very well. Others may remain stable for a period, while some do not respond despite apparently favourable characteristics.

The possibility of a long-lasting response is one reason immunotherapy has become such an important part of modern oncology, but treatment decisions still need to balance expected benefit against possible toxicity.

The wider development of new cancer treatments also means that the role of immunotherapy continues to evolve, including how it is combined with other treatments and when it is introduced.

What Should Be Reviewed Before Starting?

Before treatment begins, the oncology team needs a clear picture of both the cancer and the patient's health.

That may include reviewing the pathology, stage, molecular and biomarker results, previous treatment and current medication. Existing autoimmune disease, previous organ transplantation and significant lung, liver or other medical problems should also be discussed.

Baseline blood tests are usually needed, and further assessments may be appropriate depending on the treatment and individual medical history. A private oncology consultant can help interpret these findings in the context of the proposed treatment and the patient's individual circumstances.

This initial assessment also provides a reference point for monitoring once immunotherapy begins. Because immune-related side effects can sometimes resemble other illnesses or cancer-related symptoms, recognising a change from the patient's normal health can be important.

The Right Candidate Is Defined by More Than One Test

There is rarely a simple "yes" or "no" characteristic that determines who should receive immunotherapy.

A good candidate is someone whose cancer has an established indication for the treatment and for whom the expected benefits are considered appropriate in relation to the risks. Cancer type, stage, biomarkers, molecular findings, previous treatments and medical history all contribute to that judgement.

Sometimes the treatment recommendation is straightforward. In other cases, there may be reasonable questions about immunotherapy alone, combination treatment or an entirely different approach.

If the proposed treatment is difficult to interpret, a second opinion can provide another specialist review of the diagnosis, tumour results and recommended treatment without assuming that the original plan needs to change.

About Dr James Wilson

Immunotherapy has created important new treatment possibilities, but selecting it appropriately requires careful consideration of both the cancer and the individual patient.

Dr James Wilson is a consultant clinical oncologist in full-time private practice in Central London, specialising in lung cancer, melanoma and advanced radiotherapy. His work includes systemic cancer treatments such as immunotherapy, with a focus on helping patients understand why a treatment has been recommended and how it fits into the wider plan for their care.