HISTOLOGICAL GRADING IN GASTRIC LYMPHOMA - PRETREATMENT CRITERIA AND CLINICAL RELEVANCE

Background & Aims: Stomach-conserving therapy in primary gastric non-H odgkin's lymphoma (mucosa-associated lymphoid tissue [MALT]-NHL) is in creasingly gaining importance as an alternative to surgery. As a conse quence, surgical pathologists have to define histological criteria in pretreatment endoscopic biopsy specimen samples not only to make the d iagnosis but also to recognize minor tumor components that may infer a significantly adverse impact on prognosis. The aim of this study was to define histological criteria for clinically significant tumor progr ession in pretreatment endoscopic biopsy specimens. Methods: In a cons ecutive series of 106 patients with gastric MALT-NHL, the prognostic i mpact of large cell components was assessed by semiquantitative analys is of clusters and diffusely intermingled malignant blasts. Results: I n low-grade MALT-NHL, a category with a diffuse large cell component o f 1%-10% with or without nonconfluent clusters of blasts could be sepa rated with a significantly worse prognosis (10-year disease-specific s urvival, 90% vs. 75%). No clinical parameters of known prognostic sign ificance could account for this difference. Conclusions: It is possibl e to define criteria in endoscopic biopsy specimens to recognize clini cally relevant tumor progression. To serve as a guideline in the choic e of treatment, these criteria should be validated prospectively in fu ture clinical trials.