Abstract
Multimodal therapy concepts have been successfully implemented in the treatment of locally advanced gastrointestinal malignancies. The effects of neoadjuvant chemo- or radiochemotherapy such as scarry fibrosis or resorptive changes and inflammation can be determined by histopathological investigation of the subsequent resection specimen. Tumor regression grading (TRG) systems which aim to categorize the amount of regressive changes after cytotoxic treatment mostly refer onto the amount of therapy induced fibrosis in relation to residual tumor or the estimated percentage of residual tumor in relation to the previous tumor site. Commonly used TRGs for upper gastrointestinal carcinomas are the Mandard grading and the Becker grading system, e.g., and for rectal cancer the Dworak or the Rödel grading system, or other systems which follow similar definitions. Namely for gastro-esophageal carcinomas these TRGs provide important prognostic information since complete or subtotal tumor regression has shown to be associated with better patient’s outcome. The prognostic value of TRG may even exceed those of currently used staging systems (e.g., TNM staging) for tumors treated by neoadjuvant therapy. There have been some limitations described regarding interobserver variability especially in borderline cases, which may be improved by standardization of work up of resection specimen and better training of histopathologic determination of regressive changes. It is highly recommended that TRG should be implemented in every histopathological report of neoadjuvant treated gastrointestinal carcinomas. The aim of this review is to disclose the relevance of histomorphological TRG to accomplish an optimal therapy for patients with gastrointestinal carcinomas.
Highlights
Multimodal treatment has been successfully introduced in the therapy of gastrointestinal malignancies
There exist many tumor regression grading (TRG) systems which aim to categorize the amount of regressive changes after cytotoxic treatment – mostly they refer to the amount of therapy induced fibrosis in relation to residual tumor [14, 15] or the estimated percentage of residual tumor in relation to the previous tumor site [12, 16,17,18,19]
In summary, assessing tumor response to neoadjuvant treatment has been shown to be feasible by histopathological examination of the resected specimens in gastrointestinal carcinomas
Summary
Multimodal treatment has been successfully introduced in the therapy of gastrointestinal malignancies. There exist many tumor regression grading (TRG) systems which aim to categorize the amount of regressive changes after cytotoxic treatment – mostly they refer to the amount of therapy induced fibrosis in relation to residual tumor [14, 15] or the estimated percentage of residual tumor in relation to the previous tumor site [12, 16,17,18,19]. Context it should be stressed, that especially the presence of foamy histiocytes has been shown to be most specific for regression due to previous cytotoxic treatment while stromal changes like fibrosis, granulating inflammation following endogenous tumor necrosis can be observed in untreated carcinomas [12] Another frequent finding of adenocarcinomas treated by neoadjuvant therapy is the presence of acellular mucin lakes [12, 21, 22]. No residual tumor/tumor without detectable tissue of tumor) bed + chemotherapy effect
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