Locally Advanced Colorectal Cancer: True Peritoneal Tumor Penetration is Associated with Peritoneal Metastases

Background Findings show T4 colorectal cancer (CRC) to be a risk factor for the development of peritoneal metastases (PM). Heterogeneity regarding peritoneal involvement of T4 tumors might explain the wide range of reported PM incidences (8–50%). Hyperplastic and mesothelial inflammatory reactions complicate evaluation of the exact primary tumor involvement of the peritoneal layer. This retrospective cohort study aimed to assess the association between either inflammatory peritoneal reaction or peritoneal involvement of the primary tumor and the risk of PM.