Background: Precise preoperative profiling of breast tumors could facilitate fuller consideration of (neo)adjuvant therapies.
Methods: Diagnostic core biopsy (DCB) accuracy in profiling the primary tumor was prospectively studied in 95 patients with operable breast cancer. The histological type and grade (hematoxylin and eosin staining) and membrane receptor status (semiquantitative immunohistochemistry for estrogen [ER] and progesterone [PR] receptors, as well as Her-2 antigen expression) were assigned by the DCB before surgery. These measures were then compared with those of the definitive surgical specimen available after operation.
Results: DCB correctly ascribed tumor type and grade and ER, PR, and Her-2 receptor status in most cases (correlating exactly in 97.5%, 77%, 68%, 71%, and 60%, respectively) with at least moderate concordance (weighted kappa, >.41). When miscategorized, DCB consistently tended to upscore the receptor stain intensity compared with the surgical specimen (22%, 19%, and 27% had higher ER, PR, and Her-2 categorical scores, respectively). ER H-scores correlated best in specimens that stained strongly (224.4 +/- 3 vs. 215.5 +/- 5) and were significantly higher on DCB in those that stained either moderately (195.6 +/- 8.2 vs. 156.8 +/- 5.1; P < .0001) or weakly (157.1 +/- 24.8 vs. 81.4 +/- 4; P = .02). DCB accurately identified all tumors with clinically important ER and Her-2 expression. Furthermore, it promoted three patients into the therapeutically significant range of ER (n = 1) or Her-2 (n = 2) expression. ER negativity on DCB (n = 25) indicated a high-grade tumor (88%), although 11 (44%) patients also overexpressed Her-2. Significant Her-2 expression (n = 16) on DCB predicted the tumor as being poorly differentiated (80%) and both ER and PR negative (67%).
Conclusions: DCB accurately profiles clinically relevant measures of primary tumor cell differentiation. It also reliably categorizes patients with regard to (neo)adjuvant therapy before radical surgery is attempted.