An ultrashort stereotactic body radiation therapy (SBRT) method allowed safe and effective treatment of lung metastases in a fraction of the time thought to be needed, according to a study presented on October 26 at the American Society of Radiation Oncology (ASTRO) annual meeting.
In the randomized phase II study of 90 patients with limited disease spread (from one to three lung metastases), one session (28 Gy) with SBRT delivered similar results as four sessions with 12 Gy each (48 Gy).
The primary endpoint was safety, gauged by severe adverse event rates among patients. Researchers reported that tolerability for both regimens was acceptable; the rate of grade 3+ events within one year of treatment was 5% for the single-arm method compared with 3% for four sessions.
One year after treatment, disease-free survival rates were 59% for a single session of treatment and 60% for four sessions, researchers reported. Local control rates were also similar at 93% and 95%.
The data suggest a bright future in radiation oncology for such ultrashort treatments, which are more in demand during the COVID-19 pandemic, researchers suggested in a statement from ASTRO. Results were featured in an October 26 press briefing along with other SBRT data at the ASTRO meeting, held this year in a virtual format from October 24-28.
The study -- Stereotactic Ablative Fractionated Radiotherapy versus Radiosurgery for Oligometastatic Neoplasia to the Lung (SAFRON-II) -- was sponsored by the Trans-Tasman Radiation Oncology Group (TROG) and conducted across 13 centers in Australia and New Zealand.
If the results are maintained with further follow-up, the data suggest that patients with a small number of lung metastases could be treated in an "extremely efficient manner" in one session, said moderator Dr. Sue Yom, PhD, during the ASTRO press briefing. This saves time in the hospital for patients, which is very significant for their quality of life, said Yom, a professor of radiation oncology at the University of California, San Francisco.
