With the development of surgical instruments and improved surgical techniques, more and more patients with low rectal cancer can get the effect of the radical cure while preserving the anus. Still, nearly 60%-90% of patients will undergo low anterior resection after surgery Syndrome (down anterior resection syndrome, LARS) LARS can seriously affect patients′ quality of life after surgery. This article will explain the concept, symptoms, possible pathogenesis, prevention, and treatment measures of LARS and provide help for the diagnosis, treatment and prevention of LARS.

[Objective]To investigate the difference of ultrasound characteristics between pure mucinous carcinoma(PMC)and fibroadenoma(FA)of the breast.[Methods]Ultrasound data of 50 continuous patients with breast PMC from January 2012 to January 2021 and 100 continuous patients with breast FA from June 2018 to January 2019 in Sun Yat-sen Memorial Hospital of Sun Yat-sen University were retrospectively reviewed.The ultrasound characteristics of the two groups were evaluated according to the 2013 BI-RADS Ultrasound Atlas,and the differences in age,maximum diameter and ultrasound characteristics between the two groups were compared.[Results]The median age of PMC patients was 47 years and that of FA patients was 33 years.The age of PMC patients was higher than that of the FA group,and the differ-ence between the two groups of patients was statistically significant(P<0.001).The median maximum diameter of PMC pa-tients was 2.4 cm,which was greater than that of the FA group(1.8 cm),and the difference was statistically significant(P=0.001).Of the PMC,70%(35/50)were irregular,82%(41/50)were parallel to the skin,92%(46/50)had no circum-scribed margin,72%(36/50)were hypoechoic,and 68%(34/50)had enhanced posterior echo.Of the FA,69%(69/100)were oval or round,98%(98/100)were parallel to the skin,54%(54/100)had circumscribed margin,98%(98/100)were hypoechoic,and 75%(75/100)had no posterior features.The differences in the above ultrasound characteris-tics between the PMC and FA groups were statistically significant(P<0.001,P=0.001,P<0.001,P<0.001,P<0.001).There was no significant difference between calcifications and blood flow.[Conclusions]Compared with the FA group,pa-tients with PMC are older and the diameter of the lesions are larger.On ultrasound,the morphology and margin of most breast PMC still show the growth characteristics of invasive cancer.Meanwhile,the posterior echo of PMC is enhanced,which is a unique manifestation.