SAN DIEGO – , according to a new multicenter, open-label, randomized phase III trial.
Among 224 patients in China, aged 18-70, those randomly assigned to receive volumetric-modulated arc radiotherapy of high-dose, hypofractionated thoracic radiotherapy of 54 Gy in 30 fractions had a much higher median overall survival (62.4 months) than those who received the standard dose of 45 Gy in 30 fractions (43.1 months, P = .001), reported Jiayi Yu, PhD, of Beijing University Cancer Hospital and Institute and colleagues at the annual meeting of the American Society for Radiation Oncology.
Median progression-free survival was also higher in the 54 Gy group (30.5 months vs. 16.7 months in the 45 Gy group, P = .044).
Kristin Higgins, MD, of Winship Cancer Institute of Emory University, Atlanta, provided perspective at the ASTRO session following Dr. Yu’s presentation. She noted that the study population is quite different than that of LS-SCLC patients in the United States, where patients are often older and more likely to have a history of smoking.
“We need more technical details to understand how to deliver this regimen in clinical practice, and it may not be applicable for all patients,” she said. Still, she added that “a key takeaway here is that optimizing the radiotherapy component of treatment is very important.”
Both groups received chemotherapy. “Higher-dose thoracic radiation therapy concurrently with chemotherapy is an alternative therapeutic option,” Dr. Yu said at an ASTRO presentation.
As Dr. Yu noted, twice-daily thoracic radiotherapy of 45 Gy in 30 fractions and concurrent chemotherapy has been the standard treatment for LS-SCLC for the last 20 years. Trials failed to show benefits for once-daily 66-Gy (33 fractions) or 70-Gy treatment (35 fractions), but a phase 2 trial published in 2023 did indicate that twice-daily treatment of 60 Gy (40 fractions) improved survival without boosting side effects.
For the new study, researchers tracked 224 patients from 2017 to 2021 who were previously untreated or had received specific chemotherapy treatments and had ECOG performance status scores of 0 or 1; 108 patients were randomly assigned to the 54-Gy arm and 116 to the 45-Gy arm. All were recruited at 16 public hospitals in China.
The median age in the two groups were 60 in the 54-Gy arm and 62 in the 45-Gy arm; the percentages of women were similar (45.4% and 45.7%, respectively). Most were current or former smokers (62.0% and 61.2%, respectively).
The researchers closed the trial in April 2021 because of the survival benefit in the 54-Gy arm, and patients were tracked through January 2023 for a median 45 months.
Nearly three-quarters of patients in the 54-Gy arm survived to 2 years (77.7%) vs. 53.4% in the 45-Gy arm, a 41% reduction in risk of death. Adverse events were similar between the groups, with 1 reported treatment-related death (myocardial infarction), in the 54-Gy group.
In an interview, Kenneth Rosenzweig, MD, chairman of the department of radiation oncology at Icahn School of Medicine at Mount Sinai, New York, praised the study. It’s “no surprise” that higher radiation doses are well-tolerated since “our ability to shield normal tissue has improved” over the years, said Dr. Rosenzweig, who served as a moderator of the ASTRO session where the research was presented.
However, he cautioned that hypofractionation is still “intense” and may not be appropriate for certain patients. And he added that some clinics may not be set up to provide twice-daily treatments.
Information about study funding was not provided. The study authors have no disclosures. Dr. Higgins discloses relationships with AstraZeneca and Regeneron (advisory board), Jazz (funded research), and Janssen and Picture Health (consulting). Dr. Rosenzweig has no disclosures.