ASTRO 2021: Targeted Radiation Therapy for Oligoprogressive Metastatic Breast Cancers
Posted: Monday, November 8, 2021
Stereotactic body radiotherapy (SBRT) was tested for the treatment of oligoprogressive metastatic breast cancer. Although many patients with metastatic lung cancers experienced a benefit in terms of progression-free survival, there was no apparent survival benefit for patients with advanced breast cancer. C. Jillian Tsai, MD, PhD, of the Memorial Sloan Kettering Cancer Center in New York, presented these interim analysis results at the 2021 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract LBA-3).
“We will continue to look at the important role SBRT plays in these cancers and others and also work to understand why its effectiveness was not seen across the entire study cohort,” said Dr. Tsai in an institutional press release.
This trial enrolled patients with either non–small cell lung cancer (NSCLC) or breast cancer who had received at least one line of systemic therapy but developed oligoprogressive lesions. Patients were randomly assigned 1:1 to receive either SBRT to all progressive sites plus palliative standard of care or palliative standard of care alone.
Among the 44 patients with breast cancer enrolled in the trial, 22 received SBRT and 22 were in the control group. An additional 58 patients with NSCLC were included. After a median follow-up of 51 weeks, 71 of the patients in the entire cohort had experienced disease progression, and 30 had died.
The median progression-free survival among the full cohort was 22 weeks with SBRT and 10 weeks without it (P = .005). However, there was no apparent difference in progression-free survival among patients with breast cancer (18 weeks with SBRT vs. 17 weeks with standard of care, P = .5). Grade 2 or higher adverse events occurred in eight patients receiving SBRT, including one with grade 3 pneumonitis.
Disclosure: For Dr. Tsai’s disclosures, visit plan.core-apps.com.