Investigation of three alternative histopathological scoring methods at the invasive tumour front in colorectal cancer

Abstract

Although the characteristics at the invasive tumour front in colorectal cancer (CRC) are simple to assess, they are not included in routine pathology reports because they lack reproducibility and standardisation. In this study, we aimed to validate alternative scoring methods at the invasive tumour front in a large cohort of stage I–III CRC. The retrospective analysis was performed on haematoxylin and eosin–stained sections from 538 patients. At the invasive tumour front, tumour characteristics were scored using three alternative methods: the Karamitopoulou method, which evaluates the percentage of infiltrative tumour; the Taskin method, a five-point grading scale; and the tumour growth pattern (TGP) method, which classifies patterns as pushing, intermediate, or infiltrative. For interobserver assessment, the Karamitopoulou and TGP methods showed good agreement while the Taskin method presented fair agreement. High scores with the Karamitopoulou and Taskin methods correlated significantly with adverse prognostic factors, particularly advanced T stage (p < 0.001), N stage (p < 0.001), and the presence of peritoneal involvement (p < 0.001). The survival rate of the TGP method demonstrated that patients with an infiltrative growth pattern had significantly worse CRC survival compared to those with pushing and intermediate growth patterns (p < 0.001) and the TGP method retained its independence as a prognostic factor in multivariable Cox regression analysis only for colon cancer-specific survival (p < 0.001). The TGP scoring method is an independent prognostic factor only for colon cancer with simple and inexpensive assessment, underlining its practicality in routine reporting. Additionally, this method could be included as an additional histopathological risk indicator with the potential to guide therapeutic decision making.