title: Predictors of circumferential resection margin involvement in surgically resected rectal cancer: A retrospective review of 23,464 patients in the US National Cancer Database.
abstract: BACKGROUND
  The circumferential resection margin (CRM) is a key prognostic factor after rectal cancer resection. We sought to identify factors associated with CRM involvement (CRM+).
  
  
  METHODS
  A retrospective review was performed of the National Cancer Database, 2004-2011. Patients with rectal cancer who underwent radical resection and had a recorded CRM were included. Multivariable analysis of the association between clinicopathologic characteristics and CRM was performed. Tumor <1 mm from the cut margin defined CRM+.
  
  
  CONCLUSIONS
  Of 23,464 eligible patients, 13.3% were CRM+. Factors associated with CRM+ were diagnosis later in the study period, lack of insurance, advanced stage, higher grade, undergoing APR, and receiving radiation. Nearly half of CRM+ patients did not receive neoadjuvant therapy. CRM+ patients who did not receive neoadjuvant therapy were more likely to be female, older, with more comorbidities, smaller tumors, earlier clinical stage, advanced pathologic stage, and CEA-negative disease compared to those who received it.
  
  
  CONCLUSIONS
  Factors associated with CRM+ include features of advanced disease, undergoing APR, and lack of health insurance. Half of CRM+ patients did not receive neoadjuvant treatment. These represent cases where CRM status may be modifiable with appropriate pre-operative selection and multidisciplinary management.
authors.affiliation: Roswell Park Cancer Institute, Department of Surgical Oncology, Elm & Carlton Streets, Buffalo, NY, 14263, USA. Electronic address: eisar.al-sukhni@roswellpark.org.
authors.forename: Eisar
authors.initials: E
authors.lastname: Al-Sukhni
authors.affiliation: Roswell Park Cancer Institute, Department of Biostatistics, Elm & Carlton Streets, Buffalo, NY, 14263, USA.
authors.forename: Kristopher
authors.initials: K
authors.lastname: Attwood
authors.affiliation: Roswell Park Cancer Institute, Department of Surgical Oncology, Elm & Carlton Streets, Buffalo, NY, 14263, USA.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Gabriel
authors.affiliation: Roswell Park Cancer Institute, Department of Surgical Oncology, Elm & Carlton Streets, Buffalo, NY, 14263, USA.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Nurkin
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology / Q000473:pathology* / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D012004:Rectal Neoplasms / Q000453:epidemiology / Q000473:pathology* / Q000601:surgery*; D012189:Retrospective Studies; D014481:United States / Q000453:epidemiology; D055815:Young Adult
keywords: Adenocarcinoma; Pathology; Rectal neoplasms; Surgical