The treatment of all MRI-defined low rectal cancers in a single expert centre over a 5-year period: is there room for improvement?

Aim: Outcomes following treatment for low rectal cancer still remain inferior to those for upper rectal cancer. A clear definition of ‘low’ rectal cancer is lacking and consensus is more likely using a definition based on MRI criteria. This study aimed to determine disease presentation and treatment outcome of low rectal cancer based on a strict anatomical definition. Method: A low rectal cancer was defined as one with a lower border below the pelvic attachment of the levator muscles on sagittal MRI. One hundred and eighty consecutive patients with tumours defined by this criterion between 2006 and 2011 were identified from a prospectively managed departmental database. Results: One hundred and eighteen patients (66%) underwent curative resection and 12 (7%) palliative resection. Eleven patients (6%) were entered into a ‘watch and wait’ (W&W) protocol; 10 others (5%) were not fit to undergo any operation. Some 26 patients (14%) had nonresectable local or metastatic disease. An R0 resection was the most important factor influencing survival after curative surgery. R+ resections occurred in 12% of non-abdominoperineal excisions, 11% of abdominoperineal excisions and 47% of extended resections. Overall survival was similar in the curative resections compared with the W&W patients. In 23 of the 96 (24%) treated with neoadjuvant chemoradiotherapy there was a persistent clinical or a pathological complete response. Conclusion: In curative resections, a clear margin is the most important determinant of survival. In 24% of the patients treated with neoadjuvant chemoradiotherapy, surgery could potentially have been avoided. There is scope for improvement in the treatment of locally advanced rectal cancers.