Prognostic implications of surgical specimen quality on the oncological outcomes of open and laparoscopic surgery in mid and low rectal cancer

PURPOSE: Determine differences in pathologic outcomes between laparoscopic (LAP) and open surgery (OPEN) for mid and low rectal cancer and its influence in long-term oncological outcomes. METHODS: Retrospective case matched study at a tertiary institution. Adults with rectal cancer below 12 cm from the anal verge operated between January 2005 and September 2018 were included. Primary outcomes were quality of specimen, overall survival (OS), disease-free survival (DFS), and local recurrence (LR). RESULTS: The study included 311 patients, LAP = 108 (34.7%), OPEN = 203 (65,3%). A successful resection was accomplished in 81% of the LAP group and in 84.5% of the OPEN (p = 0.505). No differences in free distal margin (LAP = 100%, OPEN = 97.5%; p = 0.156) or circumferential resection margin (LAP = 95.2%, OPEN = 93.2%; p = 0.603) were observed. However, mesorectum quality was incomplete in 16.2% for LAP and in 8.1% for OPEN (p = 0.048). OS was 91.1% for LAP and 81.1% for OPEN (p = 0.360). DFS was 81.4% for LAP and 77.5% for OPEN (p = 0.923). Overall, LR was 2.3% without differences between groups. CONCLUSIONS: Laparoscopic approach could affect the quality of surgical specimen due to technical aspects. However, if principles of surgical oncology are respected, minor pathologic differences in the quality of the mesorectum may not influence on the long-term oncologic outcomes.