Comparison of the prognostic significance of current and modified histological grades in breast carcinomas

Paraffin sections of 185 breast carcinomas were reexamined in order to compare the current SBR histoprognostic grade (SBR) with to modified methods of grading recently proposed by two groups, Le Doussal et al (MSBR) and Elston et al (SBR-Elston). In each tumor, the SBR, MSBR, SBR-Elston, and each of their components were correlated with recurrence, metastases and survival rates (follow up 7 to 96 months, m = 52, SD = 19) (Kaplan-Meier test). The Nottingham prognostic index (NPI) was computed for each patient, the histological type reevaluated and both were also correlated with the patient follow up. Our results show that the three methods of grading were significantly (p < 0.0001) correlated. The three grades, were significantly correlated with metastases and survival, but not with the recurrence rates. The differentiation, the nuclear pleomorphism and the mitoses count also correlated with the metastases rate and overall survival but the mitoses number appeared to be a stronger prognostic indicator. The MSBR grading made it possible to refine the prognostic of the tumors usually scored as SBR grade 2. The NPI significantly correlated with metastases and survival (p < 0.0001), whereas the histological types were found to have no prognostic significance.