Key clinical point: Women with apparently unifocal, non–triple-negative breast cancer (BC) who underwent preoperative magnetic resonance imaging (MRI) and did not have any occult malignancy may safely forgo radiation therapy.
Major finding: Preoperative MRI detected malignant occult lesions in 11% of patients with BC. At 5 years, the ipsilateral invasive recurrence rate was very low (1.0%; upper 95% CI 5.4%) in patients with no occult malignancy who did not receive adjuvant radiotherapy.
Study details: Findings are from the prospective 2-arm PROSPECT study that included 443 patients with non–triple-negative, clinical stage T1N0, apparently unifocal BC who underwent MRI, of whom 201 patients underwent breast-conserving surgery without radiotherapy and 242 women were deemed ineligible for radiotherapy omission.
Disclosures: This study was funded by the Breast Cancer Trials, Australia, and other sources. The authors declared no conflicts of interest.
Source: Mann GB et al. Postoperative radiotherapy omission in selected patients with early breast cancer following preoperative breast MRI (PROSPECT): Primary results of a prospective two-arm study. Lancet. 2023 (Dec 5). doi: 10.1016/S0140-6736(23)02476-5