Principles of gynaecological chemotherapy and radiotherapy

The reasons why tumours are destroyed and normal tissues recover after radiotherapy are complex and poorly understood. Therapeutic effects depend on differences in intrinsic radiosensitivity and the ability to repair and repopulate between normal and malignant tissue. Some tumours contain hypoxic cells which are a source of radioresistance. At present, most treatments are carried out using a linear accelerator, which produces ‘skin-sparing’ radiation and can treat deep-seated tumours. Brachytherapy (short-distance treatment) with implanted or inserted internal radiation sources is an essential part of the radiation treatment of cervical carcinoma.

Chemotherapeutic agents currently in use are cytotoxic and affect both normal and malignant cells. Side effects include bone marrow suppression, nausea and vomiting, epilation, and renal, cardio- and neurotoxicity. Ideally, agents with different mechanisms of action should be given in combination to overcome potential drug resistance. Multiple drugs should have differing patterns of toxicity so the highest tolerable doses can be given. As most gynaecological chemotherapy treatments are palliative, patients should be selected with great care. The palliative value of treatment must be balanced against the risk of side effects.