Background: In 1987 Jass described a modified staging system for colorectal cancer using two anatomical criteria in common with the Dukes system; extent of spread through the bowel wall and the presence or absence of lymph node involvement. Additionally it used two 'biological' criteria; the nature of the expanding margin of the tumour (pushing or infiltrating), and the presence or absence of lymphocytic infiltration within the tumour. This study aims to determine whether a combination of the Dukes and Jass staging systems provides a better predictor of five year survival in patients with colorectal cancer than Dukes stage alone.
Method: The Dukes and Jass stages along with vital status at five years were recorded for all 612 patients undergoing resection for colorectal cancer at the Royal Bolton Hospital and the Beaumont (BMI) Hospital, Bolton between 1991 and 1998. Kaplan-Meier survival curves with log rank test were used to show how survival correlated with Jass group stratified by Dukes stage.
Results: Both the Dukes B and the Dukes C tumours could be divided into groups with significantly different five year survival rates when stratified by Jass group. Five year survival for Dukes stage B, Jass group II tumours was 73.74% compared to Dukes B Jass III tumours whose survival was 51.38% (P = 0.0018). Five year survival for Dukes C Jass III tumours was 43.18% and for Dukes C Jass IV survival was 24.39% (P = 0.0029).
Conclusion: By combining the biological criteria of the Jass staging system with the anatomically based Dukes system, both Dukes B and C tumours can be divided into groups with significantly different five year survival figures.