Development of novel prognostic score based on the indicators reflecting the tumor glandular differentiation and microenvironment for patients with colorectal cancer

Abstract Purpose: Development of prognostic stratification in patients with colorectal cancer (CRC) is an urgent concern. Desmoplastic reaction (DR) is a tissue reaction, speculated to represent the tumor microenvironment. DR types have been established as independent prognostic indicators in CRC. However, DR has not been included in the prognostic nomograms. We aimed to analyse the prognostic significance of combined histopathological indicators reflecting both tumor glandular differentiation and microenvironment. Methods: We selected 331 consecutive patients with CRC who underwent surgical resection in the Department of Surgery at Kansai Medical University (KMU). Histological glandular differentiation grading scores (HGDSs) were classified as 2 (0 point), 3-4 (1 point), and 5-6 (2 points). Tumor buddings (TBs) were classified as TB1 (0 point), TB2 (1 point), and TB3 (2 points). Lymph node metastasis was classified as pN0 (0 point), pN1 (1 point), and pN2 (2 points). pT1 or 2 was considered as 0 point; pT3 or 4 + DR non-immature type, 1 point; and pT3 or 4 + DR immature type, 2 points. Preoperative carcinoembryonic antigen (CEA) levels were classified as <5.0 ng/mL (0 point) and ≧5.0 (1 point). After summing these five factors (0-9 points), scores I (0-2 points), II (3-4 points), III (5-6 points), and IV (7-9 points) were defined. Results: The Kaplan-Meier curves showed significant differences in disease-specific survivals among scores, which were more useful than those in the current AJCC Eighth Classification, especially in patients with p-stages I, II, and III. Conclusion: The usefulness of this scoring system was demonstrated. This is the first prognostic nomogram to include DR.