Total mesorectal excision in the treatment of rectal cancer: a view from the USA.

Abstract

The technique of total mesorectal excision (TME) has sparked much controversy in the surgical community with its reported advantages of reduced local recurrence, improved survival, and reduced need for adjuvant therapy. TME is the total excision of the tumor with precise, sharp dissection to include midrectum and integral mesentery of the hindgut which envelopes the midrectum. In a compiled series of over 10,000 patients treated for rectal cancer, the local recurrence rate for surgery alone was 18.5%. Proponents of TME report local recurrence rates from 3.5% to 7.3% and survival rates greater than 80% at 5 years. Histopathological studies suggest that a proportion of patients will be at increased risk of local recurrence if adequate circumferential and distal mesorectal margins are not achieved as proposed in TME. Unlike any other cancers, there appears to be a great deal of surgeon variability in the treatment of rectal cancer, and local recurrence rates range from 5% to 30%. There is an unanswered question about the high rate of recurrence with the abdominoperineal resection where the principals of TME are followed and a wide excision is performed. Further questions concerning TME include clinical function, anastomotic dehiscence, sexual function, and adjuvant therapy. There are also detrimental functional costs of more distal anastomoses as required by TME, and further, more distal anastomoses are associated with increased leak rates and potentially increased morbidity and mortality. In the hands of its proponents, TME has commendable results and achieves outcomes superior to others that use combined surgery and adjuvant therapy. Unfortunately, experienced surgeons using apparently similar dissection techniques have not been able to reproduce such good results. Potential explanations include variations in technical expertise, patient and tumor selection bias, and differences in the extent of follow-up. The functional costs, increased anastomotic leak rates, and increased need for diversion must be weighed against potential reduced local recurrence rates in patients with mid and upper rectal cancers.