Abstract
Background The long-term outcome after local excision of T1 colorectal cancer (CRC) remains
unknown. The aim of this study was to examine clinical and histopathological risk
factors for recurrence in patients with T1 CRC undergoing endoscopic resection.
Methods This was a retrospective registry-based population study on prospectively collected
data of all patients with nonpedunculated T1 CRC undergoing only local excision (no
salvage surgery) in Sweden between 2009 and 2018. Potential risk factors for recurrence,
including age, sex, tumor location, resection margins, lymphovascular, perineural,
and submucosal invasion, grade of differentiation, and mucinous subtype, were analyzed
using univariate and multivariate cox regression.
Results Median follow-up time was 60 months, and 28 /602 patients (4.7 %) had a recurrence
(13 local and 18 distant). Recurrence rate stratified by submucosal invasion was:
Sm1 3.5 % (14 /397), Sm2 6.0 % (8 /133), and Sm3 8.3 % (6 /72), with no significant
differences. Resection margins, lymphovascular and perineural invasion, grade of differentiation,
mucinous subtype, and age were not significant risk factors for recurrence. In contrast,
rectal location was found to be a significant risk factor for tumor recurrence in
multivariate analysis (hazard ratio 3.08, P = 0.006). The 3– and 5-year disease-free survival was 96.2 % and 91.1 %, respectively,
in T1 CRC patients undergoing endoscopic resection.
Conclusion Tumor recurrence was rare (4.7 %) in this large population-based study on recurrence
after local excision of nonpedunculated T1 CRC. Rectal location was an independent
risk factor for recurrence, suggesting the need for strict surveillance after endoscopic
resection of early rectal cancer.