Stereotactic Body Radiation Therapy in Octo- and Nonagenarians for the Treatment of Early-Stage Lung Cancer

Abstract

To determine the safety and efficacy of lung stereotactic body radiation therapy (SBRT) in octo- and nonagenarians and to compare their outcomes with those of younger patients. Patients with primary lung cancer treated with SBRT were identified from a multi-institutional (5 institutions) database of 1083 cases. Details of patient factors, treatment specifics, toxicity, and clinical outcomes were extracted from the database. All events were calculated from the end of radiation therapy. Estimates of local recurrence, regional recurrence, and distant metastases were calculated using the competing risk method. Cause-specific survival (CSS) and overall survival (OS) were calculated using the Kaplan-Meier method. Outcomes were compared for those aged <70, 70 to 79, and ≥80years. Univariable and multivariable analyses were performed to determine associations with CSS and OS in patients aged ≥80years. The median (range) follow-up was 1.7 (1-10) years, and median age was 75 (41-94) years. There were 305 patients aged <70years (28%), 448 aged 70 to 79years (41%), and 330 aged ≥80years (30%). There was no difference in 2-year local recurrence (4.2% vs 5.4% vs 3.7%, respectively, P=.7), regional recurrence (10.4% vs 7.8% vs 5.3%, P=.1), distant metastases (12.2% vs 7.7% vs 9.5%, P=.2), or CSS (90.6% vs 90.3% vs 90.4%, P=.6). Those aged ≥80years had significantly lower 2-year OS (73.6% vs 67.2% vs 63.3%, P<.01). The grade 3+pneumonitis rate was 1.3% versus 1.6% versus 1.5% (P=1.0) in patients aged <70, 70 to 79, and ≥80years, respectively. The 90-day mortality rates for patients aged <70, 70 to 79, and ≥80years were 1.3%, 2.5%, and 2.4% (P=.01), respectively. In patients aged ≥80years OS was associated with T category (hazard ratio 1.7; P<.01). Stereotactic body radiation therapy is a safe treatment modality in elderly patients (aged ≥80years). Despite larger tumor volumes, the tumor control outcomes were comparable to those in younger patients treated with SBRT. All patients with early-stage lung cancer, regardless of age, should be considered for treatment with SBRT.