SBRT Proves Effective in Oligoprogressive NSCLC

Stereotactic body radiotherapy (SBRT) can improve upon standard care in patients with oligoprogressive non-small cell lung cancer (NSCLC), according to research published in The Lancet Oncology.

Researchers found that adding SBRT to standard care improved progression-free survival (PFS) in patients with oligoprogressive NSCLC but not in those with oligoprogressive breast cancer.

This phase 2 study (ClinicalTrials.gov Identifier: NCT03808662) included 106 patients with oligoprogressive breast cancer (n=47) or NSCLC (n=59).

Patients were randomly assigned to receive standard care with SBRT (n=55) or standard care alone (n=51). The median follow-up was 11.6 months in the standard care arm and 12.1 months in the SBRT arm.

SBRT improved PFS in the overall cohort and in patients with NSCLC but not in those with breast cancer. In the overall cohort, the median PFS was 7.2 months for patients who received SBRT and 3.2 months for those who did not (hazard ratio [HR], 0.53; 95% CI, 0.35-0.81; P =.0035).

In patients with NSCLC, the median PFS was 10.0 months in the SBRT arm and 2.2 months in the standard care-alone arm (HR, 0.41; 95% CI, 0.22-0.75; P =.0039). In patients with breast cancer, the median PFS was 4.4 months and 4.2 months, respectively (HR, 0.78; 95% CI, 0.43-1.43; P =.43).

Results remained the same in a multivariable analysis. Patients with NSCLC had a significant PFS benefit with SBRT (HR, 0.33; 95% CI, 0.16-0.66; P =.0019), and patients with breast cancer did not (HR, 0.79; 95% CI, 0.37-1.65; P =.53).

In addition, patients in the SBRT arm remained on their current systemic therapy longer than patients in the standard care arm. The median duration of time on current systemic therapy was 8.1 months in the SBRT arm and 5.3 months in the standard care-alone arm (P =.014).

SBRT was not associated with improved overall survival in the entire cohort (HR, 0.99; 95% CI, 0.55-1.81; P =.40), in patients with NSCLC, or in those with breast cancer. However, the researchers noted, the study was not powered to detect an overall survival benefit.

The rate of grade 2 or higher adverse events (AEs) was 41% in the standard care arm and 62% in the SBRT arm. The most common grade 2 or higher AEs (in the SBRT and standard care arms, respectively) were decreased lymphocyte count (40% vs 20%), anemia (29% vs 12%), and decreased neutrophil count (22% vs 12%).

Grade 2 or higher treatment-related AEs occurred in 9 patients in the SBRT arm. These AEs included grade 2 gastro-esophageal reflux disease in 3 patients, grade 2 and 3 pain exacerbation in 2 patients, grade 2 anemia in 2 patients, grade 3 radiation pneumonitis in 1 patient, and grade 2 brachial plexopathy in 1 patient.

“This study, together with published literature, supports the identification of oligoprogression in patients with metastatic NSCLC, which could be effectively treated with SBRT, distinct from the systemic progression seen in patients with breast cancer,” the researchers concluded.

They added, however, that confirmatory phase 3 data are needed.

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.

This article originally appeared on Cancer Therapy Advisor