Objective   To investigate the clinical value of quantifiable pull-out resection and ultra-low anastomosis for the treatment of low rectal cancer.

  Methods   Sphincter preserving surgery was performed on 97 patients with low rectal tumors, 2-5 cm away from the dentate line.The operation on the abdominal region was conducted on the basis of the principle of total mesorectal excision. During the operation on the perineum, the tumor was excised from the anus, and macroscopically quantifiable excision was conducted in accordance with the degree of pathological differentiation.Simultaneously, the mesorectal "tongue" was also removed.To determine the scope of the surgical resection, frozen sections of the lower margin of the tumor were prepared during the surgery.An ultra-low anastomosis of the colon and rectum was performed on the patients.On the basis of the length of the quantifiably excised distal intestinal canals, the patients were grouped into three: the 1 cm excision, 1.5 cm excision, and≥2 cm excision groups.The rates of local recurrence in the three groups were observed, and the relationship between the length of resection and recurrence at the intestinal stoma was analyzed.The coincidence rate of cancer-free residuals and the pathological positive rate of the mesorectal "tongue" during and after the surgery were calculated.The patients were divided into three groups using the different spaces from the stoma to the dentate line as bases: the dentate line group, 0-1 cm group, and 1-2 cm group.The functions of the anus in controlling stool and fecal incontinence in these groups were evaluated.Finally, an investigation on the degree of satisfaction of the patients was surveyed.

  Results   No patient died during the surgery in all groups.The incidence of complications was 5.2%and the rate of local recurrence was 6.2%.The 3-and 5-year survival rates were 83.3%and 72.6%, respectively.The recurrence rates of the three groups with different resection lengths were 2.1%, 9.7%, and 11.1%, respectively.No significant differences were observed in the three groups.The coincidence rate of cancer -free residues was 100%, and the pathological positive rate of the mesorectal "tongue" was 1.03%during and after the surgery. Nine months after the surgery, the evaluation results of satisfactory anal functions were as follows: 87.0%in the dentate line group, 97.1%in the 0-1 cm group, and 100.0%in 1-2 cm group.No significant differences were observed in the three groups.Fecal incontinence was not found in these cases at 6 months after surgery, and the rate of satisfaction exceeded 85%in all patients.

  Conclusion   The quantifiable pull-out resection and anastomosis as a mode of anus-preserving surgery is safe and feasible in patients with low rectal cancer.