Acute toxicity and 90-day mortality were low in older patients with stage I non–small cell lung cancer who were treated with stereotactic body radiotherapy.

Real-world rates of acute toxicity and 90-day mortality were low in patients with stage I non–small cell lung cancer (NSCLC) treated with stereotactic body radiotherapy (SBRT), according to study findings published online ahead of print in the Journal of Thoracic Oncology.

“Notably, of interest for clinical practice, patient’s calendar age (even >80 y) was not related to the risk of acute toxicity or 90-day mortality,” reported corresponding author Peter S.N. van Rossum, MD, PhD, and study coauthors.

The study included 7,279 patients with stage 1 NSCLC from the prospective Dutch Lung Cancer Audit for Radiotherapy database, which includes all patients with lung cancer in the Netherlands who received radiotherapy with a curative intent. Patients in the study received treatment with SBRT between 2017 and 2021.

According to the study, the mean age of patients was 72.5 years, with a fifth of patients older than 80 years. Half of the patients were male, 73.3% had WHO performance scores of 0 to 1, and 64.6% had cT1a-b tumors, mostly in the upper lobes.

Examining Acute Toxicity With SBRT

The study found a 3.8% incidence of acute toxicity, defined as radiation pneumonitis grade 2 or higher or non-hematologic toxicity grade 3 or higher within 90 days of SBRT completion.

Independent predictors of acute toxicity included WHO performance score of 2 or higher, lower forced expiratory volume in 1 second and diffusion capacity for carbon monoxide, no pathology evidence of NSCLC, middle or lower lobe tumor location, cT1c-cT2a tumor stage, and higher mean lung dose. Patient age, sex, and prescribed tumor biologically equivalent dose had no independent relationship with acute toxicity, researchers reported.

The rate of 90-day mortality was 1.7%. More than a quarter (27.9%) of patients who died had acute toxicity. Analysis found three independent predictors for 90-day mortality: acute toxicity, WHO performance score of 2 or higher, and male sex.

“In addition to shedding light on risk factors for SBRT toxicity and mortality and their relative and independent contributions, prediction models for acute toxicity and 90-day mortality were created…,” researchers wrote. “Satisfactory model performances were achieved, which enables clinical use in individualized provision of risk numbers to patients and guidance in treatment decision-making, ideally supported by future external validation efforts.”