Chemotherapy vs PARP inhibitor therapy

Chemotherapy uses medicines that interfere with the growth or division of cancer cells and may affect healthy fast-growing cells too. PARP inhibitors block a DNA-repair protein; in cancers already less able to repair DNA, this can make tumour cells more vulnerable. PARP treatment is usually an oral medicine, while chemotherapy may be given through a vein or by mouth, depending on the drug.

Chemotherapy may be considered when the cancer is responsive to a particular drug or combination, when a broad systemic effect is needed, or when treatment is intended before or after local therapy. It can also be selected when biomarker testing does not identify a suitable PARP target, when a rapid change in tumour burden is a priority, or when prior treatment history favours a known chemotherapy option.

A PARP inhibitor may be considered when tumour testing or inherited-risk assessment shows a relevant DNA-repair weakness and the cancer type has an established role for this treatment. The team checks previous platinum treatment or other therapies where relevant, current medicines, blood counts, kidney function, and whether swallowing or taking tablets reliably is practical.

Chemotherapy may lead to nausea, tiredness, mouth changes, hair loss, reduced blood counts, and infection risk, depending on the medicine. PARP inhibitors can also lower blood counts and may cause nausea, tiredness, appetite change, or digestive symptoms. Kidney function and blood counts matter for dosing. Tell the team about fever, unusual bruising, breathlessness, persistent vomiting, or worsening weakness rather than waiting for the next appointment.

Other choices may include surgery, radiotherapy, hormone treatment, immunotherapy, targeted treatment, another systemic medicine, or supportive care. A PARP inhibitor is not selected from a family history alone without the appropriate clinical and tumour context. If the cancer progresses, repeating molecular testing or reviewing stored tissue may help identify a different treatment route.

The recommendation brings together cancer type, stage, tumour DNA-repair results, inherited-risk information when relevant, previous medicines, current symptoms, and organ function. The team also considers how treatment is delivered, other medicines, work or caregiving demands, and your goals. Ask whether the decision is based on a tumour test, an inherited test, or both; how often blood tests are needed; and what change would prompt a switch.