Mid- or upper rectal tumours (>= 6 - 15 cm): T3 or T4 adenocarcinoma that is fixed or partially fixed or tethered and is potentially resectable; or Low rectal tumours (<6cm): T3 or T4 adenocarcinoma: or Node positive rectal tumours (<= 15cm): T1-4N2 or T1-4N+ where pelvic nodes approach or invade the mesorectum.