TOPLINE:
Stereotactic body radiotherapy (SBRT) and hypofractionated conventional radiotherapy led to similar tumor control and survival outcomes at 3 years in patients with peripheral and central stage I non–small cell lung cancer (NSCLC), with both groups experiencing minimal severe toxic effects.
METHODOLOGY: In patients with medically inoperable NSCLC, conventionally fractionated radiotherapy has been associated with poor local control and survival, whereas SBRT has led to better outcomes in this population. Hypofractionated conventional radiotherapy, however, may lead to better disease control than conventionally fractionated radiotherapy, but data comparing the different approaches are limited. The phase 3 LUSTRE trial, which compared SBRT vs hypofractionated conventional radiotherapy, enrolled 233 patients (mean age, 75.4 years) with medically inoperable stage T1/T2aN0M0 NSCLC across 16 Canadian centers between 2014 and 2020. Patients were randomized in a 2:1 ratio to receive either SBRT (n=154) with 48 Gy in four alternate-day fractions (peripheral tumors) or 60 Gy in eight daily fractions (central tumors) or hypofractionated radiotherapy (n=79) with 60 Gy in 15 daily fractions. Of the 64 patients with central tumors, 45 were in the SBRT group and 19 were in the hypofractionated radiotherapy group. The primary outcome was local control at 3 years. Secondary outcomes were event-free survival, overall survival, and toxic effects. The median follow-up duration was 36.1 months. TAKEAWAY: The 3-year local tumor control rate was similar between the two groups: 87.6% for patients who received SBRT and 81.2% for those who received hypofractionated radiotherapy (hazard ratio [HR], 0.61; 95% CI, 0.31-1.20). The 3-year event-free survival rates also did not significantly differ between the groups (49.1% for SBRT vs 47.5% for hypofractionated radiotherapy [HR, 1.02; 95% CI, 0.72-1.45]), and the 3-year overall survival rates were similar (63.5% vs 68.4%, respectively [HR, 1.18; 95% CI, 0.80-1.76]). Toxicity rates were low overall in both groups but were slightly higher in the SBRT group. Overall, in the SBRT group, 11% of patients with central NSCLC and 1.8% with peripheral NSCLC had a late grade 3 or 4 adverse event; in the hypofractionated radiotherapy group, 5% with central NSCLC and 2% with peripheral NSCLC had such an event. One grade 5 hemoptysis event occurred in the SBRT group. IN PRACTICE:
“The trial provides important prospective evidence evaluating SBRT, but further research is necessary to determine if SBRT is more effective than [conventional] RT for peripheral and central stage I NSCLC,” the authors concluded.
Although the trial shows that SBRT provides high rates of local control, “combining it with immunotherapy could improve regional and distant disease control, representing a significant advance in treatment,” Chen Hu, PhD, wrote in an accompanying editorial.
SOURCE:
The study, led by Anand Swaminath, MD, Department of Oncology, McMaster University, Hamilton, Ontario, was published online on in JAMA Oncology.
LIMITATIONS:
Lower than expected accrual resulted in a relatively smaller sample size. The inclusion of non–biopsy-proven NSCLC in more than half the patients may limit the generalizability of the findings.
DISCLOSURES:
The study was supported by the Canadian Cancer Society Research Institute. Several authors reported having various ties with sources outside the submitted work.
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