Biomarkers of normal tissue toxicity after pelvic radiotherapy

To review the evidence for candidate biomarkers of gastrointestinal toxicity following pelvic radiotherapy to highlight recent findings of potential interest to those involved in the treatment of pelvic malignancies or the management of gastrointestinal consequences of cancer treatments.

Multiple serum and faecal biomarkers have been studied for use in the detection of gastrointestinal toxicity following pelvic radiotherapy. There is no single biomarker that has been shown to be useful and studies have been hampered by the lack of a 'gold standard' test to confirm the presence of toxicity. Given the complex effects of pelvic radiotherapy on the gastrointestinal tract, it is likely that a panel of biomarkers would be necessary in clinical practice.

Biomarkers for gastrointestinal toxicity have a potential role in determining the outcomes of current and evolving radiotherapy techniques, identifying those patients at risk of greater degrees of toxicity to facilitate individualized treatment and determining whether symptoms that develop following treatment are related to the previous radiotherapy. Outcome measurement of pelvic radiotherapy has been plagued by inaccurate terminology and crude outcome measures. An accurate and acceptable biomarker or panel of biomarkers has the potential to revolutionize cancer management from treatment planning to posttreatment care. Several candidate biomarkers show promising results, but further robust research is required to clearly identify reliable biomarkers that can be translated into clinical practice.