For LRR, patient age ( ≤ 40 vs. > 40 years) and tumor size (T1 vs. T2) were used to stratify the risk groups. Of all 1,828 patients, 974 (53.3%) had no risk factors, 766 (41.9%) had one risk factor, and 88 (4.8%) had two risk factors. The 5-year cumulative LRR rates were 1.6% with no risk factors, 3.2% with one risk factor, and 12.4% with two to three risk factors. The latter was defined as the high-risk group for LRR. The 7-year and 10-year cumulative LRR rates were 2.5% with no risk factors, 4.5% with one risk factor, and 12.4% with two risk factors (Figure 1).