Histology, tumor volume, and radiation dose predict outcomes in non-small cell lung cancer patients after stereotactic ablative radiotherapy
Menée à partir de données portant sur 442 patients atteints d'un cancer du poumon non à petites cellules de stade précoce traité par radiothérapie corporelle stéréotaxique ablative (durée médiane de suivi : 6,7 ans), cette étude met en évidence une association entre les caractéristiques histologiques des lésions, le volume tumoral, la dose de rayonnements administée et le contrôle de la maladie
Introduction : It remains unclear if histology should be independently considered when choosing stereotactic ablative body radiotherapy (SABR) dose prescriptions for non-small cell lung cancer (NSCLC).
Methods : The study population included 508 patients with 561 lesions between 2000 and 2016, of which 442 patients with 482 lesions had complete dosimetric information. Eligible patients had histologically or clinically diagnosed early-stage NSCLC and were treated with 3 to 5 fractions. The primary endpoint was in-field tumor control censored by either death or progression. Involved lobe control was also assessed.
Results : At 6.7 years median follow-up, 3-year in-field control, involved lobe control, overall survival, and progression-free survival were 88.1%, 80.0%, 49.4%, and 37.2%, respectively. Gross tumor volume (GTV, HR=1.01 per mL, p=0.0044) and histology (p=0.0225) were independently associated with involved lobe failure; GTV (HR=1.013, p=0.001) and GTV dose (cutoff of 110Gy, biologically effective dose with
α/β=10 [BED10], HR=2.380, p=0.0084) were independently associated with in-field failure. For squamous cell carcinomas, lower prescription doses were associated with worse in-field control (12Gyx4 or 10Gyx5 vs. 18Gy or 20Gyx3: HR=3.530, p=0.0447, confirmed by propensity score matching) and was independent of GTV (HR=1.014 per mL, 95% CI 1.005-1.022, p=0.0012). For adenocarcinomas, there were no differences in in-field control observed using the above dose groupings (p=0.12 and p=0.31).
Conclusions
:
In the absence of level I data, GTV and histology should be considered to personalize radiation dose for SABR. We suggest lower prescription doses (i.e., 12Gyx4 or 10Gx5) should be avoided for squamous cell carcinomas if normal tissue tolerances are met.
Journal of Thoracic Oncology , résumé, 2017