Prognostic value of Ki67 labelling index in different subtypes of invasive breast cancer

Introduction:

in breast cancer, Ki67 has been proposed as a prognostic marker leading to the recommendation to use Ki67 labelling index (LI) for choosing the appropriate systemic treatment in early breast cancer by the panel of the St. Gallen International Expert Consensus.

Methods:

Clinical and pathological data of 6500 patients who underwent oncologic rehabilitation between 06/2012 and 03/2018 were documented and analyzed in relation to proliferative capacity (Ki67).

Results:

In 4350 cases data of Ki67 were available for presentation. Mean age were significantly different in women with high Ki67 levels compared with patients with low Ki67 levels (52.5 ± 10.2 vs. 56.5 ± 9.7 years; P = 0.01). In tumors with intermediate or high Ki67 levels triple negative breast cancer (TNBC; 9.3% vs. 36.4% vs. 2.6%; P < 0.0001) or Her2neu positive tumor cells (20.7% vs. 25.8% vs. 7.3%; P < 0.0001) occurs significantly more often. High Ki67 levels also correlates with poor grading (G3, 76.2% vs. 6.9%; P = 0.0001), lymph node metastasis (N+, 37.2 vs. 30.2%; P = 0.001) or advanced tumor stage (T≥2, 53.4% vs. 31.6%; P = 0.001). Reasonable to advanced tumor stage therapy-related side effects occurs significant more often in patients with high Ki67 tumors (mastectomy 26.4% vs. 19.5%, P = 0.002; lymph edema 17.0% vs. 11.9%, P < 0.001; CIPN 58.0% vs. 18.5%, P < 0.0001). Additionally, incapacity for work was significantly longer in these patients (9.3 ± 3.5 mts vs. 7.3 ± 3.8 mts; P < 0.001).

Conclusions:

High Ki67 LI levels were more often measured in younger women or TNBC and correlates significantly with advanced tumor stage, aggressive tumor behavior and treatment related side effects.