Factors that influence the adequacy of total mesorectal excision for rectal cancer

In 1997 with the start of CRO7 trial it was agreed that adequacy of surgical resection of rectal cancer would be determined by a pathologically determined grading of the mesorectum the so called total mesorectal excision score (TME score). Scores ranged from 1-3 with 3 being a perfect specimen. The aim of this study was to investigate factors which may influence TME scores and establish if local recurrence is related to them.

Data on all patients undergoing resectional surgery for rectal cancer in our unit are entered prospectively onto a database. Pathology reports of those patients who underwent total mesorectal excision were examined and the TME scores added to the database. Categorical variables were analysed using the chi2 test, continuous variables using ANOVA. Statistical significance was taken as P < 0.05.

Between January 2000 and June 2005, 518 patients underwent surgery for adenocarcinoma of the rectum, of these, 287 patients had a total mesorectal excision for mid or lower third tumours under the care of seven colorectal surgeons. All resected specimens were scored by a Consultant GI pathologist. Two hundred and fourteen patients underwent anterior resection and 73 underwent abdomino-perineal resection. The median age of the patients was 73 years (range 38-95 years). One hundred and ninety-four patients were male. Seventy-eight patients were treated with preoperative radiotherapy, 59 short course and 19 long course. TME scores were TME1 n = 30, TME2 n = 99, TME3 n = 158. Fifteen patients developed local pelvic recurrence at 2 years. Total mesorectal excision scores were not statistically influenced by Dukes' stage, width of tumour, preoperative radiotherapy or grade of surgeon. Male patients were statistically more likely to have a TME score of 2 or 3 compared with female P = 0.04. Patients undergoing an anterior resection were statistically more likely to have a TME score of 2 or 3 compared with abdomino-perineal resection P = 0.0001. Tumours with a circumferential resection margin (CRM) of more than 1 mm were more likely to have a TME score of 2 or 3 score (P = 0.0001). There was no relationship between TME and local recurrence (P = 0.966).

There is no relationship between the TME score in patients undergoing resectional surgery for adenocarcinoma of the rectum and the development of local recurrence at 2 years. Other factors such as CRM involvement are more likely to have an impact on local recurrence. The factors that influence the quality of TME are the operative procedure of anterior resection, male gender and CRM positivity. There appear to be no deleterious effects on the TME score by Specialist Registrars performing the operation under Consultant supervision. While TME scores may be an index of a technical performance, they appear to have little role in predicting future outcomes.