Grading system for lymph vessel tumor emboli: significant outcome predictor for invasive ductal carcinoma of the breast

The purpose of this study was to confirm that the grading system for lymph vessel tumor emboli is a significant histologic outcome predictor for patients with invasive ductal carcinoma. The subjects of this study were 1042 invasive ductal carcinoma patients who did not receive neoadjuvant therapy. We classified all invasive ductal carcinomas according to the grading system for lymph vessel tumor emboli we devised, and performed multivariate analyses with well-known prognostic factors. Of 1042 carcinomas, 666, 250, 97, and 29 were classified according to the grading system for lymph vessel tumor emboli as grade 0 (no lymph vessel invasion), grade 1, grade 2, and grade 3, respectively. The univariate analyses showed that the difference in outcome between the group with grade 0 and the group with grade 1 was not significant, but that survival time was significantly shorter in the group of patients with grade 2 carcinomas than in the group with grade 1 carcinomas and significantly shorter in the group of patients with grade 3 carcinomas than in the group with grade 2 carcinomas. Multivariate analyses demonstrated that having a grade 2 or grade 3 carcinoma significantly increased the hazard rates for tumor recurrence and tumor-related death in the patients as a whole as well as in both the group of patients with nodal metastasis and the group without nodal metastasis. The grading system for lymph vessel tumor emboli is an excellent histologic grading system for predicting the outcome of patients with invasive ductal carcinoma of the breast.