Treating oligoprogression with stereotactic body radiotherapy (SBRT) improves progression-free survival (PFS) in patients with non-small cell lung cancer (NSCLC), according to a phase 2 trial presented at the 2022 ASTRO Annual Meeting.
The trial showed that administering SBRT to oligoprogressing lesions improved PFS, when compared with standard of care (SOC) alone, in patients with NSCLC. However, patients with breast cancer who had oligoprogressing lesions did not derive the same benefit from SBRT.
This study (CURB; ClinicalTrials.gov Identifier: NCT03808662) included 59 patients with NSCLC and 46 patients with breast cancer. All patients had 5 or fewer extracranial oligoprogressing lesions, and they had previously received at least 1 line of systemic therapy.
For this trial, all patients received SOC systemic treatment. They were randomly assigned to receive SBRT as well or to receive SOC alone. In the breast cancer cohort, 24 patients were assigned to SBRT-SOC and 23 to SOC alone. In the NSCLC cohort, 31 patients were assigned to SBRT-SOC and 28 to SOC alone.
The primary endpoint was PFS. The median PFS was 7.2 months in the SBRT arm and 3.2 months with SOC alone (P =.005).
The PFS benefit with SBRT was driven primarily by patients in the NSCLC cohort. In that group, the median PFS was 10 months with SBRT and 2.2 months with SOC alone (P =.0015). In the breast cancer cohort, the median PFS was 4.4 months with SBRT and 4.2 months with SOC alone. (P =.2).
The pattern of failure was different between the cohorts. Patients with NSCLC were more likely to show progression in existing lesions, whereas patients with breast cancer were more likely to develop new lesions (P =.002).
The median time to new systemic therapy was significantly longer in the SBRT arm than in the SOC-alone arm — 8.1 months and 5.3 months, respectively (P =.014). The median time to new systemic therapy was 11 months among NSCLC patients and 3.9 months among breast cancer patients (P =.003).
Overall survival was similar between the treatment arms (P =.40), and this was true for NSCLC and breast cancer.
There was no significant difference in toxicities between the treatment arms. Grade 2 or higher adverse events occurred in 61% of patients in the SBRT arm and 40% of those in the SOC-alone arm (P =.13).
Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Tsai CJ, Yang JT, Guttmann DM, et al. Final analysis of consolidative use of radiotherapy to block (CURB) oligoprogression trial – A randomized study of stereotactic body radiotherapy for oligoprogressive metastatic lung and breast cancers. ASTRO 2022. October 23-26, 2022. Abstract LBA07.