Histopathological risk stratification of pT1 colorectal cancer: novel insights into established risk factors

The proportion of submucosal invasive (pT1) colorectal cancer (CRC) diagnoses has increased substantially since the introduction of CRC screening programmes. A distinct attribute of pT1 CRCs is that they can be potentially cured through local excision. With advancements in endoscopic or minimally invasive surgical resection techniques, local excision has become the primary treatment modality for the majority of these malignant polyps. After local excision, the decision regarding the need for additional surgical intervention is primarily based on the presence of histopathological risk factors for lymph node metastasis (LNM). Because of the implications for the patient, careful evaluation of these risk factors by pathologists is of great importance. In recent years, lots of attention has been paid to improve the histopathological risk classification of pT1 CRCs. This review article aims to provide a comprehensive overview of the established risk features, address the challenges encountered during histopathological assessment, and explore potential future directions for the histopathological evaluation of pT1 CRCs.