# Patient-Centered Insights from the POWER Trial: Pre-Operative Window of Adjuvant Endocrine Therapy to Inform Radiation Therapy Decisions in Older Women with Early-Stage Breast Cancer

> **NIH NIH R21** · UNIVERSITY OF VIRGINIA · 2024 · $175,328

## Abstract

Our proposal aims to improve and individualize the treatment of early-stage breast cancer in women aged 65
years and older with a novel use of a three-month course of pre-operative endocrine therapy (pre-ET). Early-
stage breast cancer is traditionally treated with breast conserving surgery (BCS) followed by adjuvant radiation
therapy (RT) and a 5- to10-year course of adjuvant endocrine therapy (AET). Long-term data from two
randomized controlled trials demonstrate that omission of RT in older women with estrogen receptor positive,
early-stage breast cancer who are treated with AET does not result in a decreased survival. However, over
70% of women still receive RT, due in part to physician and patient reluctance to omit a treatment in light of
concerns about AET toxicity and adherence. Optimal choices for older breast cancer patients require
considering data-based recommendations, life expectancy, co-morbidities and patient preferences. We will
evaluate the use of pre-ET as a novel experiential tool to inform adjuvant therapy decisions, predict long-term
AET adherence and to reduce decisional conflict and regret, addressing the following specific aims: Aim 1: To
assess whether pre-ET changes patients’ and treating physicians’ preference for adjuvant RT. This test
exposure will provide patients with the information they need to choose among the treatment options after
BCS. We hypothesize that a 3-month course of pre-ET will reduce patients’ and physicians’ preferences for
adjuvant RT by 10% from baseline preferences. We will also assess whether patient-reported outcomes during
pre-ET predict AET adherence at 2 years. We will obtain exploratory data on tumor response to pre-ET by
evaluating tumor proliferation indices before and after pre-ET. Aim 2: To measure the effect of pre-ET on
decisional outcomes for adjuvant therapy after BCS. We will apply the Ottawa Decision Support
Framework to evaluate the effects of a trial of endocrine therapy on decisional conflict and decisional regret,
framing pre-ET as a decision support intervention. We will measure decisional regret at 1 and 2 years after
BCS. We hypothesize that pre-ET will reduce decisional conflict and regret, and that decisional conflict and
regret scores will be associated with 1- and 2-year adherence to AET. The use of pre-ET in the proposal
represents a patient-centered treatment approach and may ultimately lead to a paradigm shift in the way that
early-stage breast cancer is treated in older women, allowing for optimization assignment of adjuvant therapy,
increased adherence to planned treatment regimens and decreased decisional regret.

## Key facts

- **NIH application ID:** 10745737
- **Project number:** 5R21CA277311-02
- **Recipient organization:** UNIVERSITY OF VIRGINIA
- **Principal Investigator:** Shayna Lefrak Showalter
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $175,328
- **Award type:** 5
- **Project period:** 2022-12-01 → 2025-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10745737

## Citation

> US National Institutes of Health, RePORTER application 10745737, Patient-Centered Insights from the POWER Trial: Pre-Operative Window of Adjuvant Endocrine Therapy to Inform Radiation Therapy Decisions in Older Women with Early-Stage Breast Cancer (5R21CA277311-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10745737. Licensed CC0.

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