Application of quantitative analysis to biologic profile evaluation in breast cancer.

ABSTRACT

BACKGROUND: The biologic profile of 907 infiltrating breast carcinomas was determined considering estrogen receptor (ER) and progesterone receptor (PR), proliferation index (PI) and c-erbB-2/Neu expression. The relationship with pathologic parameters (lymph node status, size, histotype) were studied by a multivariate analysis. The clinical prognostic power of biologic profile also was evaluated for 265 patients. METHODS: In 907 infiltrating breast carcinomas, the quantitation of ER, PR, an PI was obtained with an image analysis system (CAS 200, Becton Dickinson Cell Analysis Systems, San Jose, CA); Neu was evaluated semiquantitatively. A clinical study of 265 patients was performed (median follow-up, 42.5 months). RESULTS: Seventy-seven percent of tumors were ER-positive, 70% were PR-positive, 58% had a high PI, and 35% were Neu-positive. The overall analysis indicated a direct correlation between ER and PR (Spearmans' rho [rs] = 0.47, P < 0.001) and an inverse correlation between PI and ER (rs = -0.39, P < 0.001), PI and PR (rs = -0.32, P < 0.001), Neu and ER (rs = -0.20, P < 0.001), and Neu and PR (rs = -0.21, P < 0.001). Cluster analysis, performed based on the biologic profile (ER, PR, PI, c-erbB-2/Neu expression), identified two final groups of tumors with different pathologic features. This study showed a longer relapse free interval for patients with ER- and PR- positive tumors (P = 0.016 and P = 0.007) and low PI and Neu-negative tumors (P < 0.001 and P = 0.047). CONCLUSIONS: These results stress the importance of the biologic profile for defining tumor behavior and patient management, leading to integration of, and eventually the substitution for, the actual staging system.