The purpose of this study was to determine the prevalence of a positive circumferential resection margin (CRM) following surgery for colon cancer in the United States. When it comes to colorectal malignancies, local control is mostly determined by the extent to which cancer has been controlled by the CRM. The involvement of CRM is unclear following colon cancer surgery. The National Cancer Database was searched for cases of colon cancer requiring surgery between 2010 and 2015. Cases with a CRM of more than 1 mm (negative margin) and those with a CRM less than or equal to 1 mm (positive margin, CRM+) were compared, taking patient and tumor characteristics into account. Rates of CRM+ were compared to what was expected in a hospital-level analysis. 

A total of 170,022 instances were found; 150,291 CRM- were considered to have no case management risk factors (CRM+), whereas 19,731 had CRM+ and additional risk factors (11.6%). More patients with pathologic T-category 4 (25.8%), 4A (24.7%), and 4B (31.5%) than those with pathologic T-category 1 (4.5%), 2 (6.3%), or 3 (10.9%) (P<0.001). Signet-ring histology (38.1% vs. 26.7% nonmucinous, and 26.9% mucinous adenocarcinoma, P<0.001), removal of 12 lymph nodes (36.5% vs. 26.1% >12, P<0.001), community versus academic/research facilities (32.7%), year (30.1% 2010 vs. 22.6% 2015, P<0.001), and hospital volume (24.5%). 

The observed-to-expected ratio for CRM+ varied from 0 to 7.899 among 1,288 hospitals, with 429 institutions recording rates greater than predicted. The prevalence of CRM+ among colon cancer diagnoses in the United States is high. There is some variation amongst hospitals, with some places having much greater rates than others. Although biology plays a significant role, CRM+ rates can be improved by interdisciplinary approaches to colon cancer treatment.