Impact of Postoperative Complications on Oncologic Outcomes After Rectal Cancer Surgery: An Analysis of the US Rectal Cancer Consortium.

Background: Postoperative complications (POCs) are associated with worse oncologic outcomes in several cancer types. The implications of complications after rectal cancer surgery are not well studied.

Methods: The United States Rectal Cancer Consortium (2007-2017) was reviewed for primary rectal adenocarcinoma patients who underwent R0/R1 resection. Ninety-day POCs were categorized as major or minor and were grouped into infectious, cardiopulmonary, thromboembolic, renal, or intestinal dysmotility. Primary outcomes were overall survival (OS) and recurrence-free survival (RFS).

Results: Among 1136 patients, the POC rate was 46% (n = 527), with 63% classified as minor and 32% classified as major. Of all POCs, infectious complications comprised 20%, cardiopulmonary 3%, thromboembolic 5%, renal 9%, and intestinal dysmotility 19%. Compared with minor or no POCs, major POCs were associated with both worse RFS and worse OS (both p < 0.01). Compared with no POCs, a single POC was associated with worse RFS (p < 0.01), while multiple POCs were associated with worse OS (p = 0.02). Regardless of complication grade, infectious POCs were associated with worse RFS (p < 0.01), while cardiopulmonary and thromboembolic POCs were associated with worse OS (both p < 0.01). Renal POCs were associated with both worse RFS (p < 0.001) and worse OS (p = 0.01). After accounting for pathologic stage, neoadjuvant therapy, and final margin status, Multivariable analysis (MVA) demonstrated worse outcomes with cardiopulmonary, thromboembolic, and renal POCs for OS (cardiopulmonary: hazard ratio [HR] 3.6, p = 0.01; thromboembolic: HR 19.4, p < 0.01; renal: HR 2.4, p = 0.01), and renal and infectious POCs for RFS (infectious: HR 2.1, p < 0.01; renal: HR 3.2, p < 0.01).

Conclusions: Major complications after proctectomy for cancer are associated with decreased RFS and OS. Given the association of infectious complications and postoperative renal dysfunction with earlier recurrence of disease, efforts must be directed towards defining best practices and standardizing care.