Targeted therapies

Drugs aimed at one specific mechanism the tumour relies on — and which only work when that target is genuinely present.

What it is

Targeted therapies are drugs designed to recognise a specific molecule or mechanism that a tumour relies on to grow. Rather than acting on every rapidly dividing cell, as classical chemotherapy does, they address one particular address.

That has an immediate consequence: they only work when the target is present. This is why molecular testing of the tumour always comes first.

How they work

The mechanisms differ, but the main families are few:

Kinase inhibitors — block an enzyme that carries the “divide” signal inside the cell. Usually taken by mouth.
Monoclonal antibodies — attach to a receptor on the cell surface and block its function.
Antibody-drug conjugates — an antibody acting as a delivery vehicle, carrying a cytotoxic payload directly to the cells bearing the target.
DNA repair inhibitors — exploit a weakness already present in certain tumours, such as those with a BRCA variant.

Who they are for

Patients whose tumour carries the corresponding target. In non-small cell lung cancer, for example, EGFR alterations or ALK rearrangements open specific options; in breast cancer, HER2 overexpression.

No target does not mean no treatment — it means the best option is a different one from those available.

What to expect

Many targeted therapies are taken as tablets at home, with regular monitoring visits. Others are given intravenously in a day unit. Most continue for as long as they are working and are tolerated.

Side effects and management

Side effects usually differ from those of chemotherapy and relate to the target itself — for instance skin rash, diarrhoea, raised blood pressure or fatigue, depending on the agent.

Most are managed effectively when reported early. Raising a symptom early almost always means simpler management and fewer treatment interruptions.

How the treatment is chosen

None of these treatments is “better” than the others in the abstract. The choice comes from the biology of the specific tumour, the stage, previous treatment, other conditions and — not least — what matters to you.

You will be told why this treatment is proposed rather than another, what it is expected to achieve, and what it will mean in practice for your daily life. If something is unclear, asking is always welcome — and so is a second opinion.

Frequently asked questions

Are targeted therapies “gentler” than chemotherapy?

Different, not necessarily gentler. They do not usually cause hair loss or marked bone marrow suppression, but they have their own side-effect profile that needs regular monitoring.

What happens if the treatment stops working?

Tumours can develop resistance over time. In many cases a next-generation drug exists for the same target, or a repeat biopsy and retesting reveals a different mechanism that can be addressed.