The use of biomarkers in predicting response to chemoradiation in locally advanced rectal cancer and prediction of complete response
Session type: Poster / e-Poster / Silent Theatre session
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.