The depth of tumor invasion beyond the outer border of the muscularis propria as a prognostic factor for T3 rectal/rectosigmoid cancer.

UNLABELLED

The distance of tumor invasion beyond the outer border of the muscularis propria (DBM) was measured whether it would be useful as a prognostic factor of the locally advanced rectal and rectosigmoid cancer was analyzed.

PATIENTS AND METHODS

One hundred patients with rectal and rectosigmoid cancer invaded beyond muscularis propria who underwent surgery between 1996 and 2000 were included in this study. Patients who died due to other disease were excluded. Univariate and multivariate analyses of the risk factors including DBM for disease-free and cancer-related survival after surgery were performed.

RESULTS

The median DBM was 4,000 microm and patients were thus classified into 2 groups by DBM (<4,000 microm and > or =4,000 microm). In univariate analysis, patients with a DBM of > or =4000 microm had a significantly poorer prognosis both for cancer-related survival (CRS) (p=0.004) and disease-free survival (DFS) (p=0.0025). Within many prognostic factors, lymphatic invasion (p=0.025), venous invasion (p=0.0402) and pattern of tumor infiltration (p=0.043) significantly correlated with DBM. In multivariate analysis with other factors including histology (p=0.0403), node status (p=0.0003), lymphatic invasion (p=0.0004), venous invasion (p<0.0001), tumor budding (p=0.0343) and pattern of tumor infiltration (p=0.0160), DBM was selected as the most significant prognostic factor for both CRS (hazard ratio (HR): 2.1682, 95% confidence interval (CI): 1.3606-3.8097, p=0.0019) and DFS (HR: 2.0654, 95% CI: 1.2696-3.8257, p=0.0075).

CONCLUSION

Since DBM was the most significant prognostic factor, it could be used to categorize T-factor in clinical staging of advanced rectal and rectosigmoid cancer.