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.