Anatomical basis for the choice of laparoscopic surgery for low rectal cancer through the pelvic imaging data—a cohort study

BACKGROUND: Low rectal cancer surgery without anus conservation needs permanent ileostomy or colostomy which seriously affects the quality of life of patients. Therefore, low rectal cancer surgery not only pays attention to the safety of surgical treatment but also to the anus conservation. METHODS: Sixty-seven patients suffering from low rectal cancer had undergone laparoscopic surgery which was analyzed through retrospective study. They were divided into the anus-conserving and non-anus-conserving groups. Thirty-five set of pelvic data was obtained from the preoperative CT and MRI images. After that, the discriminant function was obtained to predict the surgery methods for patients with low rectal carcinoma. RESULTS: Anal-conserving group discriminant function (F1) = − 33.698 + 6.045 × anal margin distance (cm) + 1.105 × T4; non-anus-conserving group discriminant function (F2) = − 14.125 + 3.138 × anal margin distance (cm) + 0.804 × T4. If F1 is greater than F2, then the case can be treated as the anus reservation while if F2 is greater than F1 the case cannot be treated anus reservation. The accuracy of the discriminant function was evaluated which was found to be 97%. CONCLUSION: The discriminant function of pelvic data provides anatomical basis for the choice of surgical methods for low rectal cancer.