Table I. Patient characteristics (N=549).

Values in parentheses are percentages unless indicated otherwise. SD: Standard deviation; CEA: carcinoembryonic antigen; 3D-CRT: threedimension conformal radiotherapy; Gy: gray; LAR: low anterior resection; APR: abdominoperineal resection; ULAR: ultra-low anterior resection; LI: lymphatic invasion; VI: venous invasion; PNI: perineural invasion; NLR: Neutrophil to lymphocyte ratio; MSI: microsatellite instability; MSI-H: high-degree microsatellite instability; MSI-L: lowdegree microsatellite instability; MSS: microsatellite stability; CRT: chemoradiotherapy; NLR: neutrophil-to-lymphocyte ratio; PLR: platelet-to-lymphocyte ratio