@article{3123177,
    title = "The Prognostic Value of Varying Definitions of Positive Resection Margin in Patients with Colorectal Cancer Liver Metastases",
    author = "Wang, J. and Margonis, G.A. and Amini, N. and Andreatos, N. and Yuan, C. and Damaskos, C. and Antoniou, E. and Garmpis, N. and Buettner, S. and Barbon, C. and Deshwar, A. and He, J. and Burkhart, R. and Pawlik, T.M. and Wolfgang, C.L. and Weiss, M.J.",
    journal = "Journal of Gastrointestinal Surgery: Official Journal of the Society for Surgery of the Alimentary Tract",
    year = "2018",
    volume = "22",
    number = "8",
    pages = "1350-1357",
    publisher = "Springer New York LLC",
    issn = "1091-255X, 1873-4626",
    doi = "10.1007/s11605-018-3748-3",
    keywords = "aged;  colorectal tumor;  female;  human;  liver resection;  liver tumor;  male;  middle aged;  minimal residual disease;  pathology;  prognosis;  surgical margin;  survival rate, Aged;  Colorectal Neoplasms;  Female;  Hepatectomy;  Humans;  Liver Neoplasms;  Male;  Margins of Excision;  Middle Aged;  Neoplasm, Residual;  Prognosis;  Survival Rate",
    abstract = "Background: Varying definitions of resection margin clearance are currently employed among patients with colorectal cancer liver metastases (CRLM). Specifically, a microscopically positive margin (R1) has alternatively been equated with an involved margin (margin width = 0 mm) or a margin width < 1 mm. Consequently, patients with a margin width of 0–1 mm (sub-mm) are inconsistently classified in either the R0 or R1 categories, thus obscuring the prognostic implications of sub-mm margins. Methods: Six hundred thirty-three patients who underwent resection of CRLM were identified. Both R1 definitions were alternatively employed and multivariable analysis was used to determine the predictive power of each definition, as well as the prognostic implications of a sub-mm margin. Results: Five hundred thirty-nine (85.2%) patients had a margin width ≥ 1 mm, 42 had a sub-mm margin width, and 52 had an involved margin (0 mm). A margin width ≥ 1 mm was associated with improved survival vs. a sub-mm margin (65 vs. 36 months; P = 0.03) or an involved margin (65 vs. 33 months; P < 0.001). No significant difference in survival was detected between patients with involved vs. sub-mm margins (P = 0.31). A sub-mm margin and an involved margin were both independent predictors of worse OS (HR 1.66, 1.04–2.67; P = 0.04, and HR 2.14, 1.46–3.16; P < 0.001, respectively) in multivariable analysis. Importantly, after combining the two definitions, patients with either an involved margin or a sub-mm margin were associated with worse OS in multivariable analysis (HR 1.94, 1.41–2.65; P < 0.001). Conclusions: Patients with involved or sub-mm margins demonstrated a similar inferior OS vs. patients with a margin width > 1 mm. Consequently, a uniform definition of R1 as a margin width < 1 mm should perhaps be employed by future studies. © 2018, The Society for Surgery of the Alimentary Tract."
}