摘要Background Total mesorectal excision(TME)has increased the rate of sphincter-preservation(SP)for more patients with low-lying rectal cancer.Here,we analyze the change of sphincter preserving rates in lower rectal cancer and their related factors.Methods We reviewed retrospectively the medical records of 316 patients with lower rectal cancers,1 to 5 cm from the anorectal line,who had surgical resections from August 1994 to November 2005.The 12-year span was divided into 2 periods:period Ⅰ(August 1994-December 1998)and period Ⅱ(January 1999-November 2005),based on the date (January 1999)when standard total mesorectal excision(TME)was introduced.The patients were divided jnto two groups based on the operation:abdominoperineal resection(APR)or SP surgery.SP rates,leakage and other clinicopathological characteristics were compared between the two time periods and between the two different groups.Results The SP rate increased significantly over the 12 years,from 44.9% in period Ⅰ to 76.2% in period Ⅱ(P=0.000).The factors significantly influencing SP included the distance of the tumor from the anorectal line,gender,time period,circumference of intramural spread and histological differentiation (P＜0.05).Significant differences were detected between the two time periods in gender,blood transfusion volume and Dukes'stage(P＜0.05).The leakage rate was 2.7% in period Ⅰ and 1.3% in period Ⅱ (P＞0.05).Conclusions Over the 12-year period of the study the SP rate in rectal cancers 1-5 cm from the anorectal line has increased significantly while the blood transfusion volume has decreased due to the introduction of TME.However,TME had no effect on operating time and leakage rates.