Cancer of the cervix is the most important female malignancy in the developing world and is mainly treated by radiotherapy. Treatment results may improve following the application of evolving laboratory techniques. Measurement of tumour radiosensitivity already seems possible using the Courtney-Mills assay. Unfortunately this requires about 5 weeks to produce clinically useful data. More rapid techniques such as the CAM assay and tests for DNA double strand breaks as predictors of radiosensitivity are being evaluated. Radiation dosage is limited by the probability of late normal tissue damage. The identification of individuals who may suffer excessive damage such as ataxia-telangiectasia hetorozygotes may enable higher doses to be given to the 'normal' majority. Cell kinetic studies have shown that repopulation is an important source of radioresistance and some tumours may respond better to accelerated hyperfractionated radiation schedules. Repair, proliferation capacity and radioresistance are all factors under genetic control. The search for the genes responsible remains a high priority.

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