Genetic predictors of normal tissue response to radiotherapy

Radiogenomics is the study of the genetic variation that underlies how a cancer patient responds to radiotherapy. Almost half of all cancer patients undergo radiotherapy at some point in their treatment, many in combination with chemotherapy. It may be necessary, therefore, to consider genetic variation involved in both chemotherapy and radiotherapy toxicity, as well as in tumour response, to provide a comprehensive personalisation of cancer treatment. There is evidence for a genetic basis for individual variation in sensitivity to radiation and in the development of radiotherapy toxicity. Genes linked with the development of toxicity include ATM, XRCC1, and TFGB1. Although a number of studies have investigated associations between single nucleotide polymorphisms in selected genes and a patient’s probability of developing radiotherapy toxicity, results are inconclusive due to small sample sizes. Large studies are now underway collecting several thousands of samples.