Background: Pathological examination of a minimum of 16 lymph nodes is recommended following surgery for gastric adenocarcinoma, despite this a longer survival is expected when 30 or more lymph nodes are examined. Small lymph nodes are difficult to identify, and fat-clearing solutions have been proposed to improve this, but there is no evidence of their clinical benefit.
Methods: Fifty D2 subtotal gastrectomy specimens were randomized for fixation in Carnoy's solution (CS) or 10% neutral buffered formalin (NBF), with subsequent fat dissection. After dissection, the residual fat from the NBF group, instead of being discarded, was immersed in CS and dissected again. Data from 25 D2 subtotal gastrectomies performed before the study were also analyzed.
Results: The mean number of examined lymph nodes was 50.4 and 34.8 for CS and NBF, respectively (p < 0.001). Missing lymph nodes were found in all cases from the residual fat group (mean of 16.9), and in eight of them (32%) metastatic lymph nodes were present; this allowed the upstaging of two patients. Lymph nodes in the CS group were smaller than those in the NBF group (p = 0.01). The number of retrieved lymph nodes was similar among the NBF and Retrospective groups (p = 0.802).
Conclusions: Compared with NBF, CS increases lymph node detection following gastrectomy and allows a more accurate pathological staging. No influence of the research protocol on the number of examined lymph nodes was observed.
Keywords: Carnoy’s solution; Lymph node excision; Lymph node revealing solution; Pathology; Random allocation; Stomach neoplasms.