Elderly Patients Undergoing SBRT for Inoperable Early-Stage NSCLC Achieve Similar Outcomes to Younger Patients: Early-Stage Non-Small Cell Lung Cancer

Abstract

A recent publication demonstrated that lung resection in patients age >65 with early stage non-small cell lung cancer (NSCLC) was associated with perioperative complications in >50% of cases. This was found to increase with age and was significantly higher for patients age ≥75. It is unclear if older patients undergoing stereotactic body radiation therapy (SBRT) face a similar increased risk. This study aims to address toxicity and survival achieved with SBRT in the elderly compared to younger patients treated at the same institution. Records of patients diagnosed with T1-3N0M0 NSCLC treated with SBRT between Sep 2007 and Aug 2013 were reviewed. SBRT was delivered in 3-5 fractions to 40-60 Gy, with a vast majority of patients receiving 54 Gy in 3 fractions. Patients were divided into 2 cohorts, age ≥75 and <75. Kaplan-Meier and Cox proportional hazard analyses were used for univariate and multivariate analyses of survival, respectively. Chi-square and logistic regression analyses were used for univariate and multivariate toxicity assessment, respectively. We compared overall survival (OS), local recurrence–free survival (LRFS), and distant recurrence–free survival (DRFS) between cohorts. Two hundred fifty-three patients were identified. Of these, 127 were ≥75 and 126 were <75. Median follow-up was 24.9 mos. There were no differences in gender, ECOG performance status, smoking status, clinical vs pathological diagnosis of NSCLC, histology (adenoca vs all others), T-stage (T1 vs T2-3), peripheral v central tumor, BED, or number of targets between the 2 groups (all P>.05). There was a trend toward less frequent mediastinal staging in the elderly (25.2% vs 34.9%, P=.10). There was no difference between patients ≥75 vs <75 in 2-year OS (48.8% vs 60.4%, P=.95) or LRFS (86.1% vs 88.4%, P=.97). There was a statistically significant difference in 2-year DRFS (89.9% vs 74.9%, HR 0.44, P=.02) favoring patients ≥75. On multivariate Cox proportional hazards analysis, age ≥75 remained associated with improved DRFS (HR 0.40, P=.02). There was no difference in acute or late grade 2-3 toxicity for patients age ≥75 vs <75. Common toxicities included fatigue, chest wall pain, and increased dyspnea/pneumonitis. Rate of grade ≥3 acute toxicity was 5.5% overall (4.7% age ≥75 vs 6.3% age <75). Rate of grade ≥3 late toxicity was 4.0% overall (3.9% age ≥75 vs 4.0% age <75). Most common acute and late grade ≥3 toxicity was increased dyspnea/pneumonitis (3.6% and 2.0%, respectively). Two patients had grade 4 acute, 1 had grade 4 late, and 1 had grade 5 late toxicity in the <75 cohort, with no grade 4-5 toxicity in the >75 cohort. To our knowledge, this is the largest single institution study to date evaluating safety and efficacy of SBRT in an elderly population. In our series, elderly patients undergoing SBRT appear to have achieved similar outcomes and toxicity compared to younger patients.