Impact of examining additional deeper sections on the pathological diagnosis of endoscopically resected early gastric cancer.

Objectives: The pathological diagnosis of endoscopically resected early gastric cancer (EGC) is performed by evaluating a few representative sections from the specimen. We aimed to determine whether evaluating twice as many sections as usual by essentially cutting the original sections in half could improve the pathological diagnosis of EGC.

Methods: We retrospectively investigated 85 EGC in 82 patients who had undergone endoscopic resection at our hospital from August 2008 to October 2012. EGC without indications of curative resection were excluded. We re-examined the original paraffin blocks after shaving away approximately half their original thickness, and evaluated whether the pathological diagnoses were affected. This technique essentially doubled the number of sections examined.

Results: Ten pathological diagnoses of 68 EGC (14.7%) were changed from curative resection to non-curative resection when we evaluated twice as many sections as in the standard method. The median tumor size was 25 mm in the changed diagnosis group versus 14.5 mm in the no change group (P = 0.03). The univariate analysis also showed that tumor size was a significant predictor of changed diagnosis (P = 0.015). Both the changed diagnosis group and no change group had no recurrence during follow up.

Conclusions: Histological evaluation of twice as many sections as usual changed the initial pathological diagnosis of EGC, although the clinical implication of an additional deeper section was controversial because there was no recurrence. Our analysis also emphasized the importance of detailed histological evaluation to confirm a radical cure in endoscopic resection, especially in the case of larger EGC.