Primary breast tumor characteristics predicting aggressive nodal involvement

Background: pN3 breast cancer is historically associated with a poor prognosis, but the biology of aggressive nodal involvement or lymphatotropism is not well understood. Methods: This retrospective study compares clinical and pathological features for 1347 breast cancer patients with pN0 disease, 560 with pN1 disease, and 100 with ≥10 positive nodes (pN3 [10] disease). Results: Compared with pN1 disease, pN3 (10) disease was more frequently associated with T3-4 primaries (9% versus 38%, P ≤ .001), lobular histology (11% versus 22%, P = .01), and inflammatory cancer (1% versus 5%, P = 0.01). pN3 (10) disease was not associated with early-onset or estrogen receptor-negative breast cancer. The 5- and 10-year overall survival for pN3 (10) patients was 64% and 21%, respectively. Conclusions: The data indicates that the prognosis for pN3 (10) patients may be improving with current treatment. Molecular pathways governing aggressive lymphatotropism appear to be independent of those associated with early-onset, estrogen receptor-negative breast cancer.