Open versus robot-assisted sphincter-saving operations in rectal cancer patients: techniques and comparison of outcomes between groups of 100 matched patients.

ABSTRACT

BACKGROUND: Although open resection using a sphincter-saving operation (SSO) remains the standard of care for rectal cancer, few studies have compared open and robot-assisted (RA) SSOs. This study aimed to compare the operative features, functional outcomes, and oncological validity of open and RA SSO for rectal cancer. METHODS: A total of 200 rectal cancer patients undergoing curative SSO were enrolled prospectively. The open and RA groups (n = 100, respectively) were matched for clinical stage and operation type. RESULTS: The mean operation time was significantly longer in the RA group than in the open group (188 vs. 103 min, P < 0.001), but it was significantly reduced in the latter half of the RA patients compared with that in the first half (164 vs. 214 min, P < 0.001). The mean distal resection margin was significantly longer in the RA than in the open group (2.7 vs. 1.9 cm; P = 0.001), but only one patient in either group had positive circumferential resection margin. Bowel peristalsis returned one day earlier in the RA than in the open group (P < 0.001). Postoperative complication rates and anorectal functional outcomes were comparable between the two groups. The operator's physical discomfort, assessed on a visual analog scale, was significantly lower in the RA than in the open group (P < 0.001). CONCLUSIONS: According to this short-term study, the RA SSO showed equivalent oncological safety, functional outcome, and morbidities to open SSO. Although the operation takes longer, the robotic system enables a technically versatile SSO with fine dissection in a limited surgical field.