Determination of the cut-off value of Ki-67 and its effect on the early recurrence and
metastasis in patients with HR+/HER2- breast cancer
MA Qin1, HOU Yu-jin1, GAO Xu-tong2, LIU Xin-lan1△
Objective To determine the cut-off value of Ki-67 expression in hormone receptor positive and human
epidermal growth factor receptor 2 negative (HR+/HER2-) breast cancer patients, and to explore the effect of different Ki-67
expression levels on the early recurrence and metastasis of breast cancer. Methods Data of 956 patients with HR+/HER2-
breast cancer diagnosed by operation and pathology in our hospital for recent 5 years were retrospectively analyzed. The
median was used to determine the cut-off value of Ki-67 expression in HR+/HER2- breast cancer. The effect of Ki-67
expression on the early recurrence and metastasis of HR+/HER2- breast cancer were analyzed. Results The median
expression of Ki-67 in 956 patients with HR+/HER2- breast cancer was 20%. There were no significant differences in the
shape and position of Ki- 67 distribution curve between different years (χ2=16.010, P>0.05). Using 20% as the cut off value
for distinguishing the expression of Ki-67, compared with the internationally accepted cut off value of Ki-67 (14%), the
consistency of the two methods was better (Kappa value = 0.846). A total of 956 patients were followed up for 4 to 71 months,
and 56 patients had recurrence or metastasis. Univariate analysis showed that Ki-67 expression level, T stage, N stage,
histological grade and vascular / nerve invasion were the influencing factors for the early recurrence and metastasis in
patients with breast cancer. Multivariate analysis showed that lymph node stage N1-N3 (HR=2.130, 95%CI: 1.200-3.781)
and Ki-67 ≥20% (HR=3.271, 95%CI: 1.441-7.421) were independent risk factors for disease-free survival (DFS) of HR+/
HER2- breast cancer. The patients with Ki-67 ≥20% will be further divided into 3 subgroup and ≥50%. Compared with <20% patients, the risk ratio of the early recurrence and metastasis increased with the increase
of Ki-67 expression level (HR=2.784, 4.409 and 6.168), and 5-year DFS decreased (94.9%, 91.3% and 87.5%). Conclusion
The cut-off value of Ki-67 expression in HR+/HER2- breast cancer is 20% in our hospital. With the increase of Ki-67
expression level, the risk ratio of early recurrence and metastasis is increased, DFS is decreased in patients with HR+/
HER2- breast cancer.
MA Qin, HOU Yu-jin, GAO Xu-tong, LIU Xin-lan. Determination of the cut-off value of Ki-67 and its effect on the early recurrence and
metastasis in patients with HR+/HER2- breast cancer[J]. Tianjin Medical Journal, 2021, 49(12): 1319-1323.