What chemotherapy drugs target

Different medicines interfere at different points. A drug may damage genetic material, prevent a cell from copying it, or disrupt the machinery used during cell division. Because chemotherapy circulates through the bloodstream, it can reach cancer cells beyond the place where a tumour began.

Chemotherapy does not identify cancer by location alone. Healthy cells that renew quickly—including cells in bone marrow, hair follicles, the mouth and the digestive tract—can be affected too. This helps explain possible tiredness, infection risk, mouth soreness, nausea, bowel changes and hair loss.

The effects depend on the medicine, dose, schedule and your health. Your oncology team chooses a regimen for the cancer type and treatment goal, then uses symptoms, examinations, blood tests and scans as appropriate to judge its effect and adjust care.

Keep an up-to-date list of medicines, supplements and allergies, and share it before treatment. Follow the team’s instructions for blood tests, hydration, food, contraception and handling tablets at home. Do not start vitamins, herbal products or over-the-counter medicines without checking for interactions.

Record new symptoms and when they occur within each treatment cycle. Contact details for daytime and out-of-hours oncology support should be easy to find; use them rather than waiting for the next appointment when symptoms are worsening.

Contact your cancer team immediately for a temperature at or above the threshold they gave you, shaking chills, new breathlessness, confusion, uncontrolled vomiting, severe diarrhoea, unusual bleeding, or an allergic-type reaction such as facial swelling or trouble breathing. Chemotherapy can reduce infection-fighting blood cells, so fever or feeling suddenly very unwell needs prompt assessment.

Use emergency services for severe breathing difficulty, collapse, chest pain or rapidly worsening symptoms. Do not take a fever-reducing medicine first unless your oncology team has instructed you to do so, because it may hide a warning sign.

Ask which drugs are planned, what part of cancer-cell growth they affect, and whether the aim is cure, disease control, reducing recurrence risk or symptom relief. Clarify how response will be checked, which side effects require an urgent call, and who to contact outside clinic hours.