For most women whose invasive breast cancer is detected early, research shows that prognosis is generally excellent. But the group includes dramatically different subgroups of patients who need to be identified in order to perform the most effective treatment.
Clinicians know that the molecule Ki67 is a good indicator of cell proliferation rate, and the marker is already used to define the aggressiveness of later stages of breast cancer. But it was not clear how effective it would be in very early stages of the disease.
Dr. Monica Giovannini and colleagues from the University of Verona in Italy analyzed 4,250 patients with early invasive breast cancer and correlated Ki67 levels with tumor size, nodal status, and other parameters.
"We found that high cell proliferation rate, measured as Ki67 levels, correlates with larger tumor size, axillary nodal involvement, higher grading, lymphovascular invasion, ER and PgR negativity, c-erbB2 overexpression, p53 mutation, younger age at diagnosis and symptomatic presentation," Dr. Giovannini said. "All these factors are well-known markers of poor prognosis."
The same findings were valid also when the 'pT1' subgroup of the very earliest stage cancers was considered. "This means that very early invasive breast cancer gathers very different tumors in terms of prognosis and Ki67 could be a reliable and easily obtainable marker in order to identify which pT1 have worse prognosis," Dr. Giovannini said.