Rawia Mohamed, Head of the Anatomical Pathology Department at Burjeel Medical City, shared a post on LinkedIn:
“Role of Ki-67 in Breast Cancer
Ki-67 reflects tumor proliferation, but its clinical utility is limited and context-dependent.
Where Ki-67 is MOST useful
1. Patients with Stage II–III or early breast cancer
- High Ki-67 is associated with:
- Higher risk of recurrence
- More aggressive tumor behavior
- In advanced disease, the primary tumor may already have metastasized, making precise proliferation prediction more difficult.
2. ER-positive / HER2-negative breast cancer
- Low Ki-67 → better response to endocrine therapy
- Ki-67 helps differentiate:
- Luminal A (low proliferation)
- Luminal B (high proliferation)
- This distinction can influence decisions about adding chemotherapy.
Important limitations
- Ki-67 should not be used alone to guide treatment
- Variability in testing and scoring affects reliability
- Clinical benefit applies only to selected patient groups
Guideline perspective (NICE)
- NICE 2017 & 2019:
- Do not recommend routine use of Ki-67
- May be considered as an adjunct prognostic factor
- Not part of standard decision algorithms
NICE Breast Cancer Guideline Update
- The NICE guideline on early and locally advanced breast cancer (NG101) was last reviewed and updated April 14, 2025. It covers diagnosis and management of early/locally advanced disease.
This guideline replaces older versions (e.g., CG80), but it still does not make Ki-67 a mandatory or routine clinical test. It may be reported in pathology panels, but standard clinical decision algorithms do not rely on Ki-67 alone.”
