Chemotherapy uses medicines to destroy cancer cells or slow their growth. It may be recommended as the main treatment for certain cancers or combined with surgery or radiation therapy. Chemotherapy given before surgery may help shrink a tumour, while treatment after surgery can help destroy remaining cancer cells and reduce the risk of recurrence. It may also be used when cancer has spread to control the disease and relieve symptoms. Whether chemotherapy is appropriate depends on the cancer type, stage and treatment goals.

Immunotherapy helps the body's immune system recognize and fight cancer cells, while targeted therapy works on specific molecules or genetic changes that help cancer cells grow and survive. These treatments can be used for selected cancers when testing shows that the tumour has characteristics likely to respond. They may be given alone or alongside other treatments. Because their effectiveness depends on the biology of the cancer, biomarker or molecular testing may help determine whether a patient is likely to benefit.

An individualized treatment plan begins with understanding the cancer in detail. The oncologist considers the cancer type, stage, grade and location, whether it has spread, previous treatments and the patient's overall health. Molecular or biomarker findings may identify therapies that are more likely to work. The oncologist also considers potential benefits, side effects, practical factors and the patient's goals and preferences. Treatment may involve one therapy or a combination of approaches, with the plan adjusted according to how the cancer responds.

Along with tests that establish the cancer type and stage, specialists may recommend biomarker or molecular testing of tumour tissue. These tests can identify particular genes, proteins or other characteristics that may influence how a cancer behaves or responds to specific treatments. Depending on the cancer, testing may help identify patients who could benefit from targeted therapy or immunotherapy. Blood tests and imaging may also be used to assess overall health and monitor treatment response. The appropriate tests depend on the specific cancer.

Cancer medicines can cause different side effects depending on the treatment and individual patient. Oncologists monitor patients throughout treatment and may use medicines, dose adjustments, treatment breaks or supportive care to manage symptoms. For example, nausea, pain, fatigue and changes in blood counts can often be addressed with appropriate medical support. Patients should report new or worsening symptoms rather than stopping treatment on their own. Prompt communication allows the cancer team to determine whether a side effect needs treatment or further evaluation.

Ask what type and stage of cancer you have, what the goal of treatment is and why a particular therapy is being recommended. It is also useful to ask about alternatives, expected benefits, possible side effects and how they will be managed. Find out how treatment will be given, how long it may continue and how it could affect your daily activities. Ask whether biomarker testing or a clinical trial is appropriate and whom to contact if you experience concerning symptoms during treatment.