Definitive, stereotactic ablative radiotherapy and endocrine therapy without surgery for select low-risk breast cancers: A prospective, phase II trial
Abstract
Background: Early-stage, hormone receptor positive (HR+) breast cancer has excellent outcomes with lumpectomy, radiotherapy, and endocrine therapy (ET), prompting interest in treatment de-escalation. Advances in stereotactic ablative radiotherapy (SABR) raise the possibility of definitive local therapy without surgery in select patients. We conducted a prospective, phase II trial (NCT02945579) evaluating SABR with ET as a non-operative strategy.
Materials and methods: Patients aged ≥ 40 years with cT1N0M0, unicentric, HR+, HER2-negative breast cancer received 3 months of ET followed by SABR in 5 fractions. Vacuum-assisted image-guided core biopsy of the tumor bed was performed 6-12 months after SABR. Patients with pathologic complete response (pCR) omitted surgery. Co-primary endpoints were pCR and 3-year progression-free survival (PFS) rates. Patient-reported outcomes were collected as a secondary endpoint. A Bayesian framework evaluated futility using posterior probabilities to assess a clinically meaningful pCR rate.
Results: Twenty patients were enrolled (median age 70.5 years). Nineteen underwent biopsy after SABR. pCR was observed in 10/19 patients (53%, 95% CI 30-73%), and 7 (37%) had near complete response. Among the 12 patients managed without surgery, median follow-up was 44.9 months. Three-year PFS was 92% (95% CI 54-99%), with one non-breast cancer-related death and no breast cancer recurrences. Longitudinal patient-reported outcomes of decisional regret and…
How strong is the evidence?
Evidence Hub reads this as a clinical trial, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 19 participants or records.
Read the paper
Related studies
- Preliminary Toxicity Analysis of 3DCRT versus IMRT on the High Dose Arm of the RTOG 0126 Prostate Cancer Trial
- Adaptive Radiotherapy for Head and Neck Cancer: Initial Clinical Outcomes from a Prospective Trial
- American Association of Physicists in Medicine Task Group 263: Standardizing Nomenclatures in Radiation Oncology
- Motion Management Strategies and Technical Issues Associated with Stereotactic Body Radiotherapy of Thoracic and Upper Abdominal Tumors: A Review from NRG Oncology
- High-dose-rate interstitial brachytherapy as a monotherapy for localized prostate cancer: treatment description and preliminary results of a phase I/II clinical trial
- Highly efficient training, refinement, and validation of a knowledge-based plan quality control system for radiotherapy clinical trials
Go deeper in Evidence Hub
Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.