Persistent High Rate of Positive Margins and Postoperative Complications After Surgery for cT4 Rectal Cancer at a National Level

Background: A more extensive resection is often required in locally advanced rectal cancer, depending on preoperative neoadjuvant treatment response. Objective: Circumferential margin involvement and postoperative outcomes after total mesorectal excision and multivisceral resection were assessed in patients with clinical locally advanced (cT4) rectal cancer at a national level. Design: This is a population-based study. SETTINGS: Data were retrieved from the Dutch Colorectal Audit. Patients: A total of 2242 of 2881 patients with cT4 rectal cancer between January 2009 and December 2017 were selected. Main Outcome Measures: Main outcomes were resection margins, postoperative complications, and mortality. Results: Multivisceral resection was performed in 936 of 2242 patients, of whom 629 underwent extended multivisceral resection. Positive circumferential margin rate was higher after multivisceral resection than after total mesorectal excision: 21.2% vs 13.9% (p < 0.001). More postoperative complications occurred after limited and extended multivisceral resections than after total mesorectal excision (44.1% and 53.8% vs 37.6%, p < 0.001). Incidence of 30-day mortality was similarly low in both groups (1.5% vs 2.2%, p = 0.20). Independent predictors of postoperative complications were age ≥70 years (OR, 1.28 [95% CI, 1.04-1.56]; p = 0.02), male sex (OR, 1.68 [95% CI, 1.38-2.04]; p< 0.001), mucinous tumors (OR, 1.55 [95% CI, 1.06-2.27]; p = 0.02), extended multivisceral resection (OR, 1.98 [95% CI, 1.56-2.52]; p< 0.001), Hartmann procedure (OR, 1.42 [95% CI, 1.07-1.90]; p = 0.02), and abdominoperineal resection (OR, 1.56 [95% CI, 1.25-1.96]; p < 0.001). Limitations: Data specifying the extent of multivisceral resections and Clavien Dindo I to II complications were not available. Conclusions: This population-based study revealed relatively high circumferential margin positivity and postoperative complication rates in patients with cT4 rectal cancer, especially after multivisceral resections, but low mortality rates.