Multi-Institutional Experience of Stereotactic Ablative Radiotherapy for Stage I Small Cell Lung Cancer
Menée à partir de données portant sur 74 patients atteints d'un cancer du poumon à petites cellules de stade T1-T2N0M0 (âge médian : 72 ans ; taille médiane de la tumeur : 2,5 cm ; durée médiane de suivi : 18 mois), cette étude multicentrique analyse, du point de vue du contrôle de la maladie, de la survie globale et de la toxicité, l'intérêt d'une radiothérapie stéréotaxique ablative, puis identifie les formes de récidive
Purpose : For inoperable stage I (T1-2N0) small cell lung cancer (SCLC), national guidelines recommend chemotherapy with/without conventionally-fractionated radiotherapy. This multi-institutional cohort study investigated the role of stereotactic ablative radiotherapy (SABR) for this population. Methods : Clinical/treatment characteristics, toxicities, outcomes, and patterns of failure were assessed in patients with histologically-confirmed T1-T2N0M0 SCLC. Kaplan-Meier analysis evaluated survival outcomes. Univariate and multivariate analyses identified predictors of outcomes. Results : From 24 institutions, 76 lesions were treated in 74 patients (median follow-up 18 months). Median age and tumor size were 72 years and 2.5cm, respectively. Chemotherapy and prophylactic cranial irradiation (PCI) were delivered in 56% and 23% of cases, respectively. Median SABR dose/fractionation was 50 Gy/5 fractions. One- and 3-year local control (LC) were 97.4% and 96.1%, respectively. Median disease-free survival (DFS) was 49.7 months (58.3% and 53.2% at 1- and 3-years, respectively). Median, 1-year, and 3-year disease-specific survival were 52.3 months, 84.5% and 64.4%, respectively. Median, 1-year, and 3-year overall survival (OS) were 17.8 months, 69.9% and 34.0% respectively. Patients receiving chemotherapy experienced increased median DFS (61.3 vs. 9.0 months, p=0.02) and OS (31.4 vs. 14.3 months, p=0.02). Chemotherapy independently predicted better outcomes for DFS/OS on multivariate analysis (p=0.01). Toxicities were uncommon; 5.2% experienced grade ≥2 pneumonitis. Post-treatment failures were most commonly distant (45.8% of recurrences), followed by nodal (25.0%), and elsewhere lung (20.8%). Median times to each were between 5-7 months. Conclusions : In the largest report on SABR for T1-2N0 SCLC to date, SABR (≥50Gy) with chemotherapy should be considered a standard option.