Patients with rectal cancers, comprising approximately 30% of these cases, are known to have an increased rate of local recurrence Ponatinib chemical structure and decreased survival time compared with patients with tumours of the colon, a result due primarily to the surgical constraints imposed by the location of the rectum within the pelvis (Wolpin et al, 2007). As a consequence, the clinical management of patients with rectal cancer differs significantly from that of the colon in terms of surgical technique, the more frequent use of radiotherapy and method of chemotherapy administration. Evidence from randomised clinical trials, meta-analyses and epidemiologic studies strongly support the treatment of rectal cancer with preoperative modalities (Colorectal Cancer Collaborative Group, 2001; Wong et al, 2007).

The Swedish Rectal Cancer Trial was the first to demonstrate an independent survival benefit and significant improvement in local control with preoperative short-course radiotherapy (25Gy delivered in five fractions over 1 week) compared with surgery alone (Swedish Rectal Cancer Trial Group, 1997). Similar findings were derived from the Stockholm II Trial with the same fractionation regimen (Martling et al, 2001). Recently, short-course preoperative radiotherapy was found to decrease these rates even further in combination with total mesorectal excision (TME) (Kapiteijn et al, 2001). Short-course continuous, hyperfractionated, accelerated radiation therapy (CHART) and conformal high-dose-rate endorectal brachytherapy (HDREB) have demonstrated high rates of complete pathologic response as well as acceptable toxicity levels and tolerable side effects (Vuong et al, 2002, 2007; Brooks et al, 2006).

Several pathological features have been identified as prognostic factors in patients undergoing preoperative radiotherapy with or without chemotherapy. The circumferential resection margin status significantly affects prognosis with 5-year overall- and recurrence-free survival, decreasing substantially with increasing R-stage (den Dulk et al, 2007; Eriksen et al, 2007; Larsen et al, 2007). R?del and co-workers investigated the tumour regression grade (TRG) on 5-year disease-free survival in more than 350 patients (Rodel et al, 2005). An independent adverse prognostic effect was observed in patients with low TRG.

Kuo et al (2007) noted an improved survival in patients with complete pathologic response and a decreased prognosis in patients with more advanced post-treatment TNM stage. Das et al (2007) observed an association Carfilzomib between complete pathologic response and loco-regional control. In addition to these pathological prognostic factors, which can only be identified post-surgically, molecular characterisation is expected to improve the identification of more aggressive or treatment-resistant tumours before therapy.