Central vs. peripheral tumor location: influence on survival, local control, and toxicity following stereotactic body radiotherapy for primary non-small cell lung cancer
Menée sur 251 patients traités entre 2007 et 2013 pour un cancer du poumon non à petites cellules de stade précoce et inopérable (durée médiane de suivi : 31,2 mois), cette étude évalue l'efficacité, du point de vue du contrôle local de la maladie et de la survie globale, et la toxicité d'une radiothérapie corporelle stéréotaxique en fonction de la localisation de la tumeur (centrale ou périphérique)
Introduction : Stereotactic body radiotherapy (SBRT) has been increasingly utilized for medically inoperable early-stage non-small cell lung cancer (NSCLC). However, a lower biological equivalent dose (BED) is often used for central tumors given toxicity concerns, potentially leading to decreased local control. We compared survival, local control, and toxicity outcomes for SBRT patients with centrally vs. peripherally located tumors. Methods : We included patients with primary cT1-2N0M0 NSCLC treated with SBRT at our institution from September 2007 to August 2013 with follow-up through August 2014. Central tumor location was defined as within 2 cm of the proximal bronchial tree, heart, great vessels, trachea, or other mediastinal structures. Kaplan-Meier analysis and multivariable Cox regression modeling were used for overall survival and local control, and the Chi-squared test and multivariable logistic regression modeling were used for toxicity. Results : We included 251 patients (111 central, 140 peripheral) with median follow-up of 31.2 months. Patients with central tumors were more likely to be older (mean 75.8 vs. 73.5 years, p=0.04), have larger tumors (mean 2.5 cm vs. 1.9 cm, p<0.001), and be treated with a lower BED (mean 120.2 Gy vs. 143.5 Gy, p<0.001). Multivariable analysis revealed that tumor location was not associated with worse overall survival, local control, or toxicity. Patients with central tumors were less likely to have acute grade >=3 toxicity than those with peripheral tumors (odds ratio 0.24, p=0.02). Conclusions : Central tumor location did not predict for inferior overall survival, local control, or toxicity following SBRT when a lower mean BED was utilized.