Abstract
AIM:To study lung function and treatment-related radiological and clinical toxicity in a cohort of patients with non-small cell lung cancer (NSCLC) who underwent Stereotactic Ablative Radiotherapy (SABR).
METHODS:31 patients with NSCLC stage IA-IB unfit/refusing surgery were treated with single Volumetric Modulated Arc Therapy with fractionation schedule depending on tumor location. Follow-up was performed at 45, 135, 225, 315 days (T45, T135.. by means of body plethysmography, diffusion capacity for CO (DLCO) and blood gas analysis.
RESULTS: preliminary analysis was performed on 31/31 patients at T45, 25/31 at T135, 22/31 at T225 and 13/31 at T315. Total lung capacity (TLC) decreased significantly,without changes in forced expiratory volume in 1s /vital capacity ratio, from 6.02±1.30 liters to 5.54±1.33 at T225 (p<0.002) and 5.14±1.43 at T315 (p<0.01). Similar trend was observed for the residual volume. Volume reduction correlated with cancer dimension (r=0.573 at T225, r=0.65 at T315) but not with dose. DLCO (but not ratio between DLCO and dilution alveolar volume DLCO/VA) decreases significantly since T45. Arterial oxygen tension (PaO2) was slightly reduced only until T135 (75.2±8.4 vs 71.9±8.5 mmHg, p<0.03) with final value of 77.2±11.3mmHg and changes correlated with DLCO reduction (p<0.04) and to the difference between plethysmographic TLC and VA (r=-0.53) suggesting an increase in ventilation inhomogeneity rather than a direct membrane damage. Low clinical toxicity profile was observed.
CONCLUSIONS:Preliminary data suggest good tolerability for SABR with slight persistent lung volume and DLCO reduction but only transient PaO2 reduction over time.
- © 2014 ERS