Management and imaging of low rectal carcinoma.

Large variations in recurrence rates have been reported with the best results following total mesorectal excision (TME) surgery for low and middle rectal cancers. However, the low rectal cancers still have higher rates of local recurrence (up to 30%) whether operated by low anterior resection or abdominoperineal excision (APE) due to high rates of circumferential margin involvement. The treatment of choice for low rectal cancers that encroach upon the potential circumferential resection margin is surgery combined with preoperative neoadjuvant treatment. Preoperative chemotherapy combined with long-term radiotherapy reduces recurrence rates and preoperative loco-regional staging can help to select the patients more likely to benefit from neo-adjuvant therapy. Surface coil MRI is the most promising modality for patient selection, which can provide good views of the circumferential resection margin especially the presence or absence of tumour encroaching the intersphincteric plane.