The oncological and surgical safety of robot-assisted surgery in colorectal cancer: outcomes of a longitudinal prospective cohort study

BACKGROUND: Colorectal cancer is one of the most common cancers worldwide. Laparoscopic colorectal surgery (LCRS) is a frequently used modality. A new development in minimally invasive surgery is robot-assisted colorectal surgery (RACRS). METHODS: Prospectively collected data of 378 consecutive patients who underwent RACRS or LCRS for stage I–III colorectal cancer from Dec 2014 to Oct 2017 were analyzed. Primary outcome was oncological outcome (radical margins, number of retrieved lymph nodes, locoregional recurrence). Secondary outcomes were distant metastases, overall and disease-free survival, operation time, conversion, length of hospital stay, and intra- and post-operative complications. RESULTS: 206 RACRS (129 colon and 77 rectal) and 172 LCRS (138 colon and 34 rectal) procedures were included. Baseline characteristics were similar. Overall median follow-up time was 15 months (0.2–36). Oncological outcome was similar. In colon cancer, radical margins were achieved in 99.3% in RACRS group versus 98.6% in LCRS group (p = 0.60), the average number of harvested lymph nodes was 16 ± 6 versus 18 ± 7 (p = 0.16), and locoregional recurrence rate in 24 months was 3.8% vs 3.8% (p = 0.99), respectively. In rectal cancer, radical margins were achieved in 89.6% in RACRS group versus 94.3% in LCRS group (p = 0.42), the average number of harvested lymph nodes was 16 ± 8 versus 15 ± 4 (p = 0.51), and locoregional recurrence rate in 24 months was 9.5 versus 5.6% (p = 0.42), respectively. Incidence of metastasis, survival rates, operation time, length of hospital stay, and number of severe post-operative complications measured by Clavien–Dindo scores did not differ between RACRS and LCRS groups. Conversion and intra-operative complication rates were significantly lower in the RACRS group as compared to the LCRS group (3% vs 9%, p = 0.008 and 2% vs 8%, p = 0.003, respectively). CONCLUSION: RACRS is safe in the treatment of patients with stage I–III colorectal cancer. Oncological outcome did not differ between RACRS and LCRS groups. RACRS had lower conversion and intra-operative complication rates.