Predictors of positive margin after definitive resection for gastric adenocarcinoma and impact of adjuvant therapies

Publication date: Available online 31 March 2017
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): Ryan M. Rhome, Erin Moshier, Umut Sarpel, Nisha Ohri, Madhu Mazumdar, Michael H. Buckstein
BackgroundPositive margins after definitive resection in gastric adenocarcinoma (GA) are associated with inferior outcomes. There is little randomized data to guide optimal adjuvant therapy after positive margin.MethodsUsing the National Cancer Database (NCDB), we identified 24,619 non-metastatic GA patients diagnosed from 2004-2013 that underwent definitive resection to analyze for predictors of positive surgical margin. Of these patients, 2,754 had positive margin (11.2%). Multivariable prevalence ratios were used to determine predictors. Survival analyses were performed with Cox proportional hazards model using several methods of propensity-score analysis.ResultsIncreasing T/N stage, high grade, and lymphovascular invasion predicted higher rate of positive margins. Asian race, treatment at academic center, and robotic surgery predicted lower rates of positive margins. Among positive margin patients with adjuvant treatment (n=1,021), with median follow-up of 55 months, age, co-morbidity score, nodal disease, and T4 disease predicted for worse overall survival (OS). Treatment at academic centers was associated with improved OS. Use of adjuvant concurrent chemoradiation (CCRT) was associated with higher OS compared to chemotherapy alone after positive margin (HR 0.72, 95% CI 0.58-0.91, p=0.005) after propensity matching adjusting for predictors of OS. The 2-year and 3-year OS for positive margin patients with chemotherapy alone was 43% and 29% respectively compared to 53% and 38% with adjuvant CCRT. The log rank p-value for survival was 0.0015.ConclusionStage, race, treatment center and surgery approach predicts for margin status after resection. Adjuvant CCRT after positive margin is associated with improved OS after accounting for available clinical variables.

Teaser

Positive margins in resected localized gastric cancer portend worse outcomes. While guidelines encourage adjuvant chemoradiation after positive margin, little prospective evidence exists to support improved outcomes. Using hospital-based analysis, predictors of positive margin include T/N stage, grade, lymphovascular space invasion, race, academic treatment center, and surgical approach. In the setting of positive margins, adjuvant chemoradiation is associated with improved overall survival after adjusting for confounding variables when compared to adjuvant chemotherapy alone.


http://ift.tt/2oju1j9