Reassessment of Declines in Pulmonary Function 1 Year or More after Stereotactic Body Radiotherapy (SBRT)
Menée sur 141 patients atteints d'un cancer du poumon non à petites cellules de stade précoce et traités par radiothérapie stéréotaxique corporelle entre 2005 et 2010 (durée médiane de suivi : 21 mois), cette étude rétrospective monocentrique évalue les capacités respiratoires plus d'un an après le traitement, notamment chez les patients présentant une maladie pulmonaire obstructive chronique modérée ou sévère
Background: Stereotactic body radiation therapy (SBRT) is standard care for patients with inoperable early-stage non-small-cell lung cancer. However, clinicians may hesitate to use SBRT in patients with severe COPD because of potential negative effects on pulmonary function. We quantitatively analyzed long-term declines in pulmonary function after SBRT to ascertain lifelong tolerability to SBRT.Methods: Between 2005 and 2010 at Ofuna Chuo Hospital, 292 patients with lung tumors were treated with SBRT. Among them, patients who underwent pulmonary function tests (PFTs) both pre-treatment and at 1 year or more after SBRT were evaluated in this retrospective analysis. Decline ratio in FEV1 and FVC was assessed (i.e., dFEV1/preFEV1 and dFVC/preFVC). Predictors were identified using univariate and multivariate analyses.Results: The 141 eligible patients had follow-up PFT at a median of 21.0 (range, 12.0–74.8) months after SBRT. Among groups with normal function, mild-moderate, or severe COPD, the median values for dFEV1/preFEV1 were 7.9%, 7.9%, and 7.4%, respectively, and for dFVC/preFVC they were 5.1%, 3.4%, and 0.5%, respectively. Low body mass index (BMI) was the only predictor for dFEV1/preFEV1 > 10%. Low BMI, high lung volume receiving >20 Gy (V20), and high pre-treatment FVC were predictors for dFVC/preFVC > 10%.Conclusions: Declines in FEV1 and FVC were small, but statistically significant in patients with normal function or mild-moderate COPD, however, non-significant in patients with severe COPD. These declines were primarily due to physiologic aging. SBRT had a limited effect on decline in long-term pulmonary function and may be an acceptable alternative to surgery for patients with comorbid lung cancer and COPD.
http://chestjournal.chestpubs.org/content/early/2012/06/20/chest.12-0207.abstract