17 July 2014
A study published recently in Nature Genetics reported that patients with variations in the TANC1 gene showed greater risk of side effects from late radiation-induced damage after radiotherapy for prostate cancer.
Although radiotherapy is one of the main treatments for prostate cancer (the predominant cancer in men in the developed world), it can result in clinically relevant side effects in up to 40% of patients in the short term, and 7.7% of patients in the longer term.
The increased risk of side-effects caused by variants in the TANC1 gene was identified from a three stage genome wide association study. The international collaborative study was performed on an initial 741 individuals who were treated with external beam radiotherapy for prostate cancer along with two replication cohorts of 633 and 368 individuals.
Notably, the study marks the path towards a predictive genomic test which could be used to personalise treatment for prostate cancer patients.
Currently, long-term side effects not only reduce survivors’ quality of life, but also limit the standard treatment intensity for all patients. This reduces the risk of adverse effects, but also decreases the probability of successful tumour control. A genomic test could optimise treatment for all, allowing stronger radiotherapy in patients with suitable genetic profiles and giving others the option of alternative treatments such as chemotherapy.
Catherine West, Professor of Radiation at the University of Manchester who also led the establishment of the International Radiogenomics Consortium that gave rise to this study said that the paper was “an exciting first step” but cautioned that more work was needed, explaining: “We now need to study perhaps 50,000 patients to identify enough genetic variants for a test that can be used clinically”.