A Randomized, Phase III Trial of Pre-Operative Window of Endocrine Therapy to Inform Radiation Therapy Decisions in Older Women with Early-Stage Breast Cancer (POWER II)

The purpose of this study is to find out if patients receiving endocrine therapy before the lumpectomy (and to better understand how they tolerate the drug(s)) would result in fewer patients receiving breast cancer surgery alone (no radiation or endocrine therapy) and fewer patients receiving breast cancer surgery plus radiation and endocrine therapy.

For more information, visit https://clinicaltrials.gov/study/NCT06507618

Inova Schar Cancer
8081 Innovation Park Drive
Fairfax, VA 22031

Inova Fair Oaks Hospital
3600 Joseph Siewick Drive
Fairfax, VA 22033

• Diagnosis of ER+, PR +/-, and HER2- non amplified invasive breast cancer and clinically negative nodes
• Females, aged ≥ 65 years
• Patient is eligible for BCS and opted for BCS
• Patient is a candidate for radiation therapy
• Patient is a candidate for endocrine therapy (tamoxifen or an aromatase inhibitor)
• Ability to take oral medication and be willing to adhere to endocrine therapy for the 3-month period prior to BCS
• Additional eligibility in protocol

• Bilateral synchronous breast cancer
• Multicentric disease
• Prior use of SERMS or aromatase inhibitors
• History of ipsilateral breast radiation therapy
• Has a known additional malignancy that is progressing and/or requires active treatment with cytotoxic chemotherapy or radiation therapy. Malignancies deemed stable and low risk for complication per investigator's judgment may be allowed after discussion with multi-site PI.
• Current or planned use of a strong CYP2D6 inhibitor (e.g., Fluvoxamine, Paroxetine) and is not able to receive an endocrine therapy agent that does not use the CYP2D6 pathway.
• Additional ineligibility in protocol