Background: Treatment of early stage rectal cancer has excellent oncological results. To reduce treatment-related mortality and morbidity and improve functional results, a focus on local resections is increasingly important.
Objective: The purpose of this study was to compare outcomes after transanal endoscopic microsurgery and total mesorectal excision for early stage rectal cancer (T1 + T2) in Norway.
Design: This was an observational study based on prospective data from the Norwegian Colorectal Cancer Registry.
Settings: The study was conducted as a national, population-based study.
Patients: All 543 patients with T1 and 1593 patients with T2 rectal cancer without distant metastases that was treated by transanal endoscopic microsurgery or total mesorectal excision without radiochemotherapy during 2000-2009 were included.
Main outcome measures: The primary outcomes were 5-year relative survival and 5-year local recurrence rate.
Results: Among 543 patients with T1 cancer, the 5-year overall survival rate was 65.3% after transanal endoscopic microsurgery versus 81.5% after total mesorectal excision (p = 0.012). Adjusted for age and sex there was no excess mortality for transanal endoscopic microsurgery (HR = 1.28 (95% CI, 0.8-1.9); p = 0.22). The 5-year relative survival rate was 96.8% after transanal endoscopic microsurgery versus 98.2% after total mesorectal excision (p = 0.603), and the 5-year local recurrence rate was 14.5% versus 1.4% (p < 0.001). Among 1593 patients with T2 cancer, 5-year overall survival was 42.1% versus 76.1% (p < 0.001), 5-year relative survival was 65.4% versus 93.9% (p < 0.001), and 5 year local recurrence rate was 11.4% versus 4.4% in the 2 groups.
Limitations: The study is limited by its observational design and that the 2 groups were different according to patient and tumor characteristics. Another limitation was the low number of transanal endoscopic microsurgery procedures.
Conclusions: Transanal endoscopic microsurgery had comparable 5-year relative survival to total mesorectal excision in T1 rectal cancer but inferior 5-year relative survival in T2 rectal cancer. Transanal endoscopic microsurgery was associated with higher local recurrence rates for both T1 and T2 tumors.