To analyze the learning curve of Da Vinci robotic-assisted radical surgery for rectal and sigmoid colon cancer and explore the optimal number of learning cases.

A retrospective analysis was conducted on the clinical data of 93 cases of Da Vinci robotic-assisted radical surgery for rectal and sigmoid colon cancer performed by the same surgeon at the Cancer Hospital, Chinese Academy of Medical Sciences from July 2021 to December 2022. The learning curve of Da Vinci robotic-assisted radical surgery for rectal and sigmoid colon cancer was constructed based on the surgical time. The optimal number of learning cases was determined according to the peak of the curve, and patients were divided into the surgery improvement group (Group A) and the surgery proficiency group (Group B) according to the learning curve for comparison of clinical parameters.

Ninety-three patients successfully underwent Da Vinci robotic-assisted radical surgery for sigmoid colon or rectal cancer. The best fitting curve equation was: curve fitting according to CUSUM values, the curve equation was y=0.006x³-1.183x²+58.840x-219.293, R²=0.857, P<0.01. The optimal number of surgeries to reach the learning curve was 33 cases. The first 33 patients were classified as the A group, and the subsequent 60 patients were classified as the B group. Compared with the Group A, the Group B had shorter operative time (144.3 min vs. 179.1 min, P=0.008), less blood loss (21.7 mL vs. 29.4 mL, P=0.010), and shorter postoperative hospital stay (7.1 d vs. 8.8 d, P=0.026).

Da Vinci robotic surgery requires a certain number of learning cases. This study suggests that 33 cases are the optimal number of learning cases. After completing 33 cases of Da Vinci robotic surgery learning, patients had shorter operative time, less blood loss, and shorter postoperative hospital stay.