Relationship between histologic features of primary breast carcinomas and axillary lymph node micrometastases: Detection and prognostic significance.

The incidence and prognostic significance of micrometastases (Mic-Met) in axillary lymph nodes (LNs) is still controversial. We compared Mic-Met detection of invasive mammary carcinomas (IMCs) in axillary LNs using second review of hematoxylin and eosin (H&E)-stained slides and immunohistochemistry (IHC) relating them with features of the primary tumor, and determining their influence on overall survival (OS) and disease-free survival (DFS). We studied 188 cases of IMCs with no axillary metastases in the initial reports. The original H&E slides of LN were re-viewed and new sections were submitted for IHC using pancytokeratin (AE1/AE3). All primary breast tumors were re-viewed and classified according to Page et al (1998) and College of American Pathologists criteria (2000). Tumors were graded using the Nottingham grading system. Kaplan-Meier curves were used to evaluate OS and DFS of 147 patients. Mic-Met detection was correlated to histologic features of primary tumor (size, type, grade, lymphatic/blood vessel invasion). Mic-Met were detected in 26/188 cases (by IHC: 23/188, 12.2%; by H&E: 12/188, 6.4%). The re-view of H&E slides showed good specificity (98.2%), but low sensitivity (39.1%), when compared with IHC. There was no relationship between features of primary tumor and Mic-Met detection, including patients with lobular carcinomas or IMCs with lobular features. There was no statistical difference in OS and DFS of patients with and without Mic-Met, but patients with Mic-Met presented lower survival curves. In conclusion, there was no relationship between histologic features of primary tumor and presence of Mic-Met, nor between Mic-Met detection and patients survival.