Background: In a prospective multicenter observational study (OCUM) neoadjuvant chemoradiotherapy (nRCT) was selectively administered depending on the risk of local recurrence and based on the distance between tumor and mesorectal fascia in pretherapeutic high-resolution magnetic resonance imaging (MRI).
Objective: Frequency and quality of abdominoperineal excision (APE) and sphincter preserving operations.
Patients and methods: Of 642 patients treated in 13 hospitals 389 received surgery alone and 253 nRCT followed by surgery. By univariate and multivariate analysis risk factors for APE were determined. Quality parameters were the quality grade of mesorectal excision, the pathohistological involvement of the circumferential resection margin and intraoperative local dissemination of tumor cells.
Results and discussion: In 12.8 % of the patients APE was performed. Independent risk factors for APE were tumor location in the lower third of the rectum and the individual hospitals, where APE varied between 0 and 32 %. This variation was chiefly caused by the different case mix. Hospitals with a high APE rate (> 30 %) treated significantly more patients with very low lying carcinomas (< 3 cm above the anal verge) and more advanced tumors. The median height of the tumor in cases of APE was nearly equal in all participating hospitals. Independent on the number of cases the quality of rectal surgery was high. Within the patient groups of primary surgery and nRCT the oncological quality parameter did not significantly differ between sphincter preservation and APE. As far as sphincter preservation is concerned the results justify a selective application of nRCT in patients with rectal carcinoma. The long-term results still have to be awaited.
Keywords: Abdominoperineal resection; Neoadjuvant chemoradiotherapy; OCUM study; Rectal carcinoma; Sphincter preservation.