PERITONEAL REGRESSION GRADING SCORE
LAST UPDATE: 08/30/2024
USE
Assess therapeutic response in peritoneal metastasis
RESPONSE
Fibrotic scars, with or without elastotic areas.
Foamy macrophages.
Infarct-like necrosis.
Acellular mucin with intervening fibrosis.
TUMOR
Viable neoplastic cells.
Dirty necrosis, containing nuclear debris in a patchy distribution.
COMMENTS
Tumor histologic grading is not recommended in reporting.
The adjacent tumor-free peritoneum may develop therapy-induced morphological changes, including inflammation and fibrosis, which can be difficult to distinguish from regressive changes in the tumor.
Multiple peritoneal biopsies may show different PRG-scores.
grading SYSTEM
PRGS 1: Complete regression with absence of tumor cells
PRGS 2: Major regression features with only a few residual tumor cells
PRGS 3: Minor regression with predominance of residual tumor cells and only a few regressive features
PRGS 4: No response to therapy, where tumor cells are not accompanied by any regressive features
images
REFERENCES
Solass, W., Kerb, R., Mürdter, T., Giger-Pabst, U., & Reymond, M. A. (2016). Pharmacokinetics of intraperitoneal doxorubicin in a rat model: impact of treatment with doxorubicin and rapamycin. Cancer Chemotherapy and Pharmacology, 78(5), 1045-1056.
Solass, W., Horvath, P., Struller, F., Königsrainer, A., & Reymond, M. A. (2015). Peritoneal carcinomatosis: quantifying the inherent and iatrogenic surgical risks. European Journal of Surgical Oncology (EJSO), 41(11), 1556-1562.
Solass, W., Handke, T., Schmidt, K., Werner, U., Graichen, A., Horvath, P., & Reymond, M. A. (2014). A novel approach to the morphological assessment of response to treatment in peritoneal metastasis: the Peritoneal Regression Grading Score (PRGS). Annals of Surgical Oncology, 21(5), 1392-1397.
Reymond, M. A., Solass, W., & Brücher, B. L. D. M. (2016). Histopathological assessment of peritoneal metastasis and response to therapy: current status and new developments. Virchows Archiv, 469(3), 255-270.
Solass, W., Sempoux, C., Detlefsen, S., Carr, N. J., & Bibeau, F. (2016). Peritoneal sampling and histological assessment of therapeutic response in peritoneal metastasis: proposal of the Peritoneal Regression Grading Score (PRGS). Pleura and Peritoneum, 1(2), 99-107.