A prospective phase II study evaluating safety and efficacy of combining stereotactic body radiation therapy with heat-based ablation for centrally located lung tumors
Mené sur 16 patients atteints d'une ou plusieurs tumeurs situées dans la région centrale du poumon (durée médiane de suivi : 26 mois), cet essai de phase II évalue l'efficacité, du point de vue des taux actuariels de contrôle local à 1 et 2 ans, et la toxicité d'un traitement combinant radiothérapie corporelle stéréotaxique et ablation thermique
Purpose : Stereotactic body radiation therapy (SBRT) and heat-based ablation (HBA) are both potentially safe and effective treatments for primary and metastatic lung tumors. Both are suboptimal for centrally located tumors, with SBRT having higher risk for significant toxicity and HBA having lower efficacy. This study evaluates the safety and efficacy of combination SBRT/HBA to see if a combined treatment can result in superior outcomes than each treatment alone. Materials/Methods : Patients with one or two primary or metastatic lung tumors ≤ 5 cm in size were enrolled on a prospective phase II trial and treated with SBRT in 3 fractions followed by HBA. Tumors < 1 cm from the central bronchial tree received a total of 36 Gy and tumors 1-2 cm away received 42 Gy. HBA was delivered within 10 days after SBRT. The primary endpoints were local control, toxicity, and degree of decline in lung function. Secondary endpoints were progression-free survival and overall survival. Results : 16 patients with 17 tumors were treated. The median follow-up time was 26 months. 15 tumors were evaluable for local control. The 1- and 2-year actuarial local control rates were 93% and 81%. Three patients experienced grade ≥ 3 toxicity; bronchial stenosis, pain, and pulmonary hemorrhage. The percent predicted forced expiratory volume in 1 second (FEV1) and functional vital capacity (FVC) decreased by 8% and 8.5% at 3 months post-treatment, respectively (p < .001 for both). Conclusions : Combining SBRT and HBA for centrally located lung tumors offers reasonable local control and toxicity despite the anatomical challenges of this location. HBA may be a reasonable supplement to SBRT when trachea/bronchus, large vessels, or esophageal constraints cannot be met with full dose SBRT, and a biologically effective dose of < 100 Gy is delivered due to an ultra-central location or large tumor size.