The use of biomarkers in predicting response to chemoradiation in locally advanced rectal cancer and prediction of complete response


Session type:

John McGrane1, Thomas Clarke2,3, David White2,3, Andrew Shaw4, Neil Smart3, Ian Daniels3,1, Melanie Osborne1
1Department of Oncology, Royal Devon & Exeter Hospital, Exeter, UK, 2University of Exeter Medical School, Exeter, UK, (HeSRU) Exeter Health Services Research Unit, 4College of Life and Environmental Sciences, University of Exeter, Exeter, UK


In locally advanced rectal cancer for surgery to be a viable treatment option it is necessary to induce clear surgical resection margins through tumour down-staging, using chemoradiotherapy (CRT). Recent publications have suggested that it may be possible to predict responses to CRT using biomarkers; however the predictive value of these biomarkers is unknown.


Aretrospective study of patients between January 2006 and December 2011 undergoing neo-adjuvant CRT for locally advanced rectal cancer was carried out. Receiver operating characteristic (ROC) analysis was undertaken to assess the predictive qualities of biomarkers in predicting a complete response to neo-adjuvant CRT.


Seventy three patients underwent neo-adjuvant CRT between January 2006 and December 2011 of which 9 patients experienced a clinical complete response (cCR) and an additional 10 patients had a pathological complete response (pCR). ROC analysis of pre- treatment Haemoglobin (Hb) concentration and post treatment lymphocyte concentration produced ROCAUC values of 0.673 and 0.618 respectively for cCR. Post treatment neutrophil concentration and pre-treatment Hb concentration produced values of 0.591 and 0.614 respectively for pCR.


There is an association between Hb concentration and response to CRT, which is independent of clinical T stage. However, no biomarkers offer a good prediction of response to neo-adjuvant CRT, and therefore it is not possible to predict response to CRT in locally advanced rectal cancer.