Prospective evaluation of early lung toxicity following three-dimensional conformal radiation therapy in non-small-cell lung cancer: preliminary results.

Abstract

Radiation pneumonitis is the restricting complication following lung cancer irradiation. The correlation between dose-volume histograms (DVHs) and pneumonitis, with a clinical, radiological, and respiratory function evaluation was assessed. Special endpoint was the evaluation of respiratory function after three-dimensional conformal radiotherapy (3D-CRT). Fifty-four patients with non metastatic non-small-cell lung cancer (NSCLC) were treated with a curative intent with 3D-CRT (66 Gy). Thirty-one patients were treated postoperatively (pneumonectomy in 9 patients) for residual tumor or massive nodal involvement (N2 or N3); 23 patients were treated with exclusive radiotherapy. Clinical evaluation, CT scan, and pulmonary functional tests were performed before and 6 weeks after irradiation. The DVHs were calculated applying lung density heterogeneity. Twenty patients had radiation pneumonitis. Irradiation significantly decreased total lung capacity. Volume of the PTV2 (more than 200 cm(3)) was a significant prognostic factor for lung complication. DVHs combined with initial pulmonary functional tests can predict pulmonary toxicity and could allow us to adjust volume that received total highest dose with acceptable toxicity.