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Early Predictive Markers and Histopathological Response to Neoadjuvant Endocrine Therapy in Postmenopausal Patients with HR+/HER2- Early Breast Cancer

  • 0Department of Breast Cancer and Reconstructive Surgery, Maria Sklodowska-Curie National Research Institute of Oncology, 02-781 Warsaw, Poland.
Cancers +

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July 29, 2025

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July 29, 2025

View abstract on PubMed

Summary

This summary is machine-generated.

Neoadjuvant endocrine therapy (NET) significantly shrinks tumors and reduces aggressiveness in postmenopausal HR+/HER2- breast cancer. Early decreases in Ki-67 and PgR indicate treatment effectiveness, aiding in monitoring and stratification.

Area Of Science

  • Oncology
  • Endocrinology
  • Pathology

Background

  • Neoadjuvant endocrine therapy (NET) is a key treatment for hormone receptor-positive (HR+)/HER2-negative breast cancer in postmenopausal women.
  • Assessing treatment response through biomarkers like Ki-67 and progesterone receptor (PgR) is crucial for optimizing therapy.

Purpose Of The Study

  • To evaluate the clinical and histopathological efficacy of NET in postmenopausal HR+/HER2- breast cancer.
  • To investigate early and late changes in Ki-67 and PgR as indicators of endocrine response.

Main Methods

  • Prospective cohort study of 127 postmenopausal patients with HR+/HER2- breast cancer receiving NET (primarily letrozole) for a mean of 7.7 months.
  • Tumor size, grade, Ki-67, and PgR were assessed pre-treatment and post-treatment (including a second biopsy after 4 weeks in 80 cases).

Main Results

  • NET significantly reduced tumor size (median shrinkage 47.0%) and histological aggressiveness.
  • Median Ki-67 decreased from 20.0% to 5.0% within 4 weeks, with 33.3% of patients showing Ki-67 < 2.7%.
  • Significant reductions in PgR expression were observed, and 67.0% showed concordant decreases in Ki-67 and PgR.

Conclusions

  • NET effectively reduces tumor burden and aggressiveness, increasing rates of breast-conserving surgery (BCS).
  • Early Ki-67 and PgR reduction can serve as surrogate markers for endocrine responsiveness in HR+/HER2- breast cancer.
  • These biomarkers support treatment stratification and monitoring during NET.

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