Diagnostic accuracy and utility of intraoperative microscopic margin analysis of gastric and esophageal adenocarcinoma.

BACKGROUND: Positive resection margins are amongst the strongest predictors of cancer-related mortality for adenocarcinoma of the stomach and esophagus. Although intraoperative pathology consultation with frozen section of margins can predict final permanent section pathology, the accuracy of this approach is not known. We sought to determine the diagnostic accuracy of frozen section margin analysis in esophagogastric adenocarcinoma and the impact that it had on surgical therapy.
METHODS: Patients with resection of esophagogastric adenocarcinoma at a single centre from 1998 to 2008 were identified. Clinicopathologic data were collected. Frozen section results were compared to permanent section assessment, and sensitivity, specificity, positive, and negative predictive values were calculated. Patients with positive margins by frozen section were reviewed to assess the impact on surgical decision-making.
RESULTS: Of 220 patients who underwent surgery for adenocarcinoma of the esophagus and stomach (esophagus: 34/220, EGJ: 106/220, stomach 80/220), 56 % had an intraoperative consultation. Of these 122 patients, 66 % underwent frozen section. All errors on frozen section occurred on the interpretation of the proximal margin. The diagnostic accuracy of frozen section at the proximal margin was 93 % with sensitivity = 67 %, specificity = 100 %, positive predictive value = 100 %, and negative predictive value = 91 %. Signet ring cells were present in 83 % of false-negative readings. Surgical management was altered in 10 of the 13 of patients who had a true positive frozen section and 9 of these patients were converted to R0 resections.
CONCLUSIONS: Although very specific, negative results on frozen section require greater caution when signet ring cells are present. For esophagogastric adenocarcinoma, frozen section alters management and may increase the rate of complete resection.