99PD - Modelling of pulmonary function test changes after stereotactic body radiotherapy for stage I NSCLC

Date 14 April 2016
Event European Lung Cancer Conference 2016 (ELCC) 2016
Session Predictive models for chemo- and radiotherapy
Topics Non-Small-Cell Lung Cancer, Early Stage
Surgery and/or Radiotherapy of Cancer
Presenter Johannes Roesch
Citation Journal of Thoracic Oncology (2016) 11 (supplement 4): S57-S166. S1556-0864(16)X0004-4
Authors J. Roesch1, B. Stam2, J. Belderbos2, H. Peulen2, M. Flentje3, M. Giuliani4, A. Hope4, M. Werner-Wasik5, Y. Hong6, I. Grills6
  • 1Department Of Radiation-oncology, Universitätsspital Zürich, 8001 - Zürich/CH
  • 2Radiotherapy, The Netherlands Cancer Institute, 1066 CX - Amsterdam/NL
  • 3Department Of Radiation Oncology, University Hospital Wuerzburg, Würzburg/DE
  • 4Department Of Radiation Oncology,, Princess Margaret Hospital, Toronto/CA
  • 5Department Of Radiation Oncology,, Thomas Jefferson Univ Hospital, Philadelphia/US
  • 6Department Of Radiation Oncology,, William Beaumont Hospital, Royal Oak/US

Abstract

Background

Surgical lung volume reduction is an established option in patients with severe pulmonary emphysema showing that resection or damage to non-functional lung volumes improves pulmonary function. We evaluated whether irradiation dose to the lung and weighting of the irradiation dose with the local lung density allows modelling of pulmonary function test changes after stereotactic body radiotherapy (SBRT) for stage I NSCLC.

Methods

A multicenter retrospective database from the Elekta lung consortium of 505 patients with early stage NSCLC treated with SBRT was analyzed. PF, in forms of FEV1 and % predicted (FEV1%) as well as DLCO and % predicted (DLCO%), were obtained before, between 0–6 months, and between 6–24 months after SBRT; this resulted in 194 and 98 patients available for analysis, respectively. Planning-CTs were analyzed and 2 Gy-equivalent mean lung dose (MLDEQD2) without GTV was calculated. Furthermore, a density weighted lung dose (MLDDWD) was introduced: EQD2 was related to density per voxel (MLDDWD=AVG(EQD2 × CT-number / AVG(CT-number)). Spearman correlations of PF and MLDEQD2 and MLDDWD were investigated (p-vale was corrected for multiple testing using Holm-Bonferroni method). Moreover, the changes in PF pre and post treatment were studied.

Results

In comparison to pre-treatment PF Wilcoxon test showed significant changes (p 

Conclusions

Although there is a large variability in PF changes post-SBRT, no dose effect relationship was observed and density weighting of the mean lung dose did also not improve the correlation.

Clinical trial identification

Legal entity responsible for the study

Department of radiation oncology, University hospital, Zürich

Funding

Elekta

Disclosure

All authors have declared no conflicts of interest.