Lack of prognostic significance of histological grade in node-negative invasive breast carcinoma.

Histological grade (HG), as modified by Elston and Ellis (Histopathology, 19: 403-410, 1991), was shown to be a significant prognostic indicator in a large group of women with invasive breast cancer, who had node-negative as well as node-positive tumors and included special types of breast cancer. The aim of this study was to determine the utility of HG as a prognostic indicator in node-negative invasive breast cancer, no special type (NN-BCA-NST), which represents the majority of cases seen in clinical practice. One hundred eighty-two women with NN-BCA-NST and who had 28-106 months follow-up (mean, 73 months; median, 71 months) were entered in the study. Bilateral and multifocal cancers, and cancers with distant metastases, were excluded. Nuclear grade (NG), tubule formation (TF), mitotic index (MI), and HG were determined and scored as described by Elston and Ellis (Histopathology, 19: 403-410, 1991). Survival analysis was performed by the Kaplan-Meier method and the log-rank test. Regression analysis was used to determine the relationship between NG, TF, and MI. There was significant correlation between NG and MI (R = 0.667, P < 0.0001) and between TF and MI (R = 0.416, P < 0.0001). NG, TF, MI, and HG did not have significant prognostic value (P = 0.3771, P = 0.7972, P = 0.2953, and P = 0.7946, respectively). HG was of no significant prognostic value even after women who received adjuvant therapy were excluded from the analysis (P = 0.3917). Our data show that the HG is not a reliable prognostic indicator in NN-BCA-NST.