PEPI Score Calculator
Estimate the Preoperative Endocrine Prognostic Index (PEPI) category after neoadjuvant endocrine therapy in ER-positive breast cancer.
What is the PEPI score?
The Preoperative Endocrine Prognostic Index (PEPI) is a clinical tool used after neoadjuvant endocrine therapy for hormone receptor-positive breast cancer. It combines surgical pathology and biomarker findings to estimate recurrence risk.
PEPI is most often discussed in the context of treatment planning after preoperative endocrine therapy, especially in postmenopausal patients with ER-positive disease. A very low score (PEPI-0) has been associated with favorable outcomes in selected patient groups.
How this calculator assigns points
This calculator uses the commonly taught PEPI point framework:
- Pathologic tumor stage: pT1/2 = 0 points, pT3/4 = 3 points
- Pathologic nodal status: pN0 = 0 points, pN+ = 3 points
- Ki-67 at surgery: ≤ 2.7% = 0 points, > 2.7% = 1 point
- ER Allred score at surgery: 3–8 = 0 points, 0–2 = 2 points
Total score range: 0 to 9 points.
Risk group interpretation
- PEPI-0 (score = 0): very low-risk group
- PEPI 1–3: intermediate-risk group
- PEPI ≥4: higher-risk group
How to use this PEPI score calculator
Enter each postoperative data point from the pathology and biomarker report:
- Select the pT stage group (pT1/2 or pT3/4).
- Select nodal status (pN0 or pN+).
- Enter Ki-67 as a percentage.
- Enter the ER Allred score from 0 to 8.
Click Calculate PEPI Score to get the total points and category, plus a breakdown showing how each variable contributed.
Clinical context and practical notes
Why PEPI is useful
PEPI helps stratify prognosis after endocrine response. In multidisciplinary practice, it can support conversations around adjuvant therapy intensity. It is not a standalone decision-maker, but it is a useful risk communication framework.
What PEPI does not replace
PEPI should be interpreted alongside full clinicopathologic context, including age, comorbidities, tumor biology, genomic assays (where relevant), treatment goals, and patient preferences.
Example
Suppose a patient has: pT2 disease, node-negative status, Ki-67 of 1.8%, and ER Allred 8 at surgery. That would be 0 + 0 + 0 + 0 = PEPI score 0, which falls into the PEPI-0 category.
Important limitations
- Different institutions may have assay variability (especially for Ki-67).
- The score is population-informed and not a guarantee for individual outcomes.
- Evidence evolves; local and current guidelines should always be followed.
- This page is educational and cannot provide personalized medical advice.
Bottom line
This PEPI score calculator gives you a quick, structured estimate of risk category based on four key post-treatment findings. Use it to support informed discussion with oncology professionals, not to replace expert clinical judgment.