Margin-driven outcomes prevail over resection planes: multivisceral surgery matches total mesorectal excision in locally advanced rectal cancer

Purpose: This study compared oncologic and perioperative outcomes between patients with locally advanced rectal cancer (LARC) treated with beyond total mesorectal excision (bTME) and those with pathologic stage III disease undergoing TME.Methods: A retrospective analysis was conducted using prospectively collected data from 580 LARC patients treated with curative-intent surgery over a 23-year period. Patients were categorized as those with clinical T4b tumors who underwent bTME with multivisceral resection (MVR) and those with pathologic stage III tumors treated with TME. Demographic, surgical, pathological, and oncologic outcomes were compared.Results: Circumferential resection margin (CRM) positivity was similar between the groups (5.3% vs. 3.6%, P=0.467). Postoperative complications occurred more often in the bTME group (28.9% vs. 16.6%, P=0.004), although major complications were comparable (P=0.812). Five-year local recurrence (10.5% vs. 9.3%, P=0.371), distant metastasis (19.7% vs. 21.4%, P=0.140), disease-free survival (64.4% vs. 66.2%, P=0.326), and overall survival (74.8% vs. 75.5%, P=0.464) demonstrated no significant differences. Within the bTME group, 32 patients (42.1%) underwent major MVR and 44 (57.9%) underwent minor MVR. CRM positivity (6.2% vs. 4.5%, P=0.999), local recurrence (12.5% vs. 9.1%, P=0.714), and distant metastasis (25.0% vs. 15.9%, P=0.388) rates were similar. Five-year disease-free survival (61.5% vs. 72.3%, P=0.454) and overall survival (68.5% vs. 74.8%, P=0.609) favored minor MVR, although the differences were not statistically significant.Conclusion: When negative circumferential margins are achieved, margin-driven bTME resections provide long-term oncologic outcomes comparable to standard TME in high-risk rectal cancer, although they are associated with higher overall complication rates.