Test to predict the behavior of breast cancer
Breast cancer behaves differently in many subgroups of patients. If we can identify subgroups in which the breast cancer is less aggressive we may be able to target our treatment to the subgroups whose breast cancer is more aggressive. Recently a test that measures how quickly cells are dividing has been used in early stage breast cancer as well to predict the aggressiveness of breast cancer tumors. This data was presented at the 2nd ESMO Scientific & Educational Conference (ESEC) in Budapest, Hungary. These findings will help physicians to decide which patients will benefit most from treatment with more intensive chemotherapy.
It is known 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 until now it was not clear how effective it would be in very early stages of the disease. The data was presented by Monica Giovannini and colleagues from the University of Verona in Italy. They 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 in the very earliest stage breast cancers as well. "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.
This data confirms that Ki67 is a prognostic indicator in early breast cancer. Patients presenting with small tumors is a real challenge in terms of treatment decisions. Whether to give chemotherapy to this sub group of patients is a major decision the oncologist has to take. Hopefully this new prognostic marker will make the decision making easier.