Does the mesorectal fat area impact the histopathology metrics of the specimen in males undergoing TME for distal rectal cancer?

The aim of this study was to evaluate whether the mesorectal fat area (MFA) has an impact on the histopathology metrics of the specimen in male patients undergoing robotic total mesorectal excision (rTME) for cancer in the distal third of the rectum. Prospectively collected data of patients undergoing rTME for resectable rectal cancer by five surgeons during 3 years were extracted from the REgistry of Robotic SURgery for RECTal cancer (RESURRECT). MFA was measured at preoperative MRI. Distal rectal cancer was defined as within 6 cm from the anal verge. Specimen metrics included circumferential resection margin (CRM) measured by pathologists as involved if < 1 mm, distal resection margin (DRM) and TME quality. Of 890 patients who underwent rTME for rectal cancer, a subgroup analysis compared 116/581 (33.4%) with MFA > 20 cm² to 231/581 (66.6%) with MFA ≤ 20 cm². The mean CRM in patients with MFA > 20 cm² was neither statistically nor clinically significantly different from patients with MFA ≤ 20 m² (6.8 ± 5.6 mm vs. 6.0 ± 7.5 mm; p = 0.544). The quality of TME did not significantly differ: complete TME 84.3% vs. 80.3%; nearly complete TME 12.9% vs. 10.1%; incomplete TME 6.8% vs. 5.6%. The DRM was not significantly different: 1.9 ± 1.9 cm vs. 1.9 ± 2.5 cm; p = 0.847. In addition, the intraoperative complication rate was not significantly different: 4.3% (n = 5) vs. 2.2% (n = 5) (p = 0.314). This prospective multicenter study did not find any evidence to support that larger MFA would result in poorer histopathology metrics of the specimen when performing rTME in male patients with distal rectal cancer.