Pathologic findings from the National Surgical Adjuvant Breast Project protocol B-06. 10-year pathologic and clinical prognostic discriminants.

BACKGROUND: Prognostic pathologic and clinical features for 10-year survival were determined from 22 pathologic and 5 clinical variables encountered in 1090 node-negative and 651 node-positive patients enrolled in NSABP protocol B-06.
METHODS: All factors were first screened univariately. Those exhibiting P values < 0.01 were entered into multivariate Cox regression models. The model with the best fit consisted of 951 negative-node and 496 node-positive patients.
RESULTS: Better survival in node-negative patients was noted for whites rather than blacks, for patients with favorable tumor types (tubular, mucinous, papillary) rather than intermediate (lobular invasive, classical medullary, and not otherwise specified [NOS] combinations) or unfavorable forms (NOS pure and atypical medullary), and for tumors with good rather than poor nuclear grade. Number of nodal metastases, degree of tumor elastosis, and patient age younger than 40 years of age and 65 years of age and older in addition to nuclear grade and race were found significant for node-positive patients. Relative risks for combinations of these prognostic factors were multiplicative.
CONCLUSIONS: The prognostic factors for node-negative patients were similar to those observed for this cohort at 8 years. Some differences noted between patients of both nodal groups in NSABP B-04 and B-06 may be related to selection requirements in the latter and hence different patient characteristics or more speculatively a change in tumor biology.