Conversion to Open Surgery During Minimally Invasive Right Colectomy for Cancer: Results from a Large Multinational European Study.

Background: The risk of conversion to open surgery is inevitably present during any minimally invasive colorectal surgical procedure. Conversions have been associated with adverse postoperative and oncologic outcomes. No previous study has evaluated the specific causes and consequences of conversion during a minimally invasive right colectomy (MIS-RC). Materials and Methods: We analyzed the Minimally invasivE surgery for oncologic Right ColectomY (MERCY) study database including patients who underwent laparoscopic or robotic RC because of colon cancer between 2014 and 2020. Descriptive analyses were performed to determine the different reasons for conversion. Uni- and multivariate logistic regressions were run to identify potential variables associated with this outcome. Cox regression analyses were used to evaluate the impact of conversion on tumor recurrence. Results: Over a total of 1574 MIS-RC, 120 (7.6%) were converted to open surgery. The main reasons for conversion were procedural difficulties related to adherences from previous abdominal surgical procedures (39.2%), or owing to large tumor size or infiltration of adjacent structures (26.7%). Only 16.7% of the conversions were caused by intraoperative medical or surgical complications. Converted patients required longer operative times and developed more postoperative complications, both overall (39.2% versus 27.5%; P  = .006) and severe ones (13.3% versus 8.3%; P  = .061). Male gender (odds ratio [OR] = 1.89 [95% confidence interval: 1.31-2.71]), obesity (OR = 1.99 [1.4-2.83]), prior abdominal surgery (OR = 1.68 [1.19-2.37]), and pT4 cancers (OR = 4.04 [2.86-5.69]) were independently associated with conversion. Conversion to open surgery was not significantly associated with tumor recurrence (hazard ratios = 1.395 [0.724-2.687]). Conclusions: Although conversion to open surgery during MIS-RC for cancer is associated with worsened postoperative outcomes, it seems not to impact on the oncologic prognosis.