CT Density in Lung Cancer Patients After Radiotherapy Sensitized by Metoclopramide : A Subgroup Analysis of a Randomized Trial

Abstract

Purpose: To investigate the lung tissue response measured with computed tomography (CT) after radiotherapy (RT) combined with metoclopramide. Patients and Methods: Patients with non-small cell lung cancer (tumor stage IIIA and IIIB), included in a multicenter, randomized phase III trial investigating the use of metoclopramide as a radiosensitizing agent, were examined with repetitive post-RT CT scans. The analysis comprised data up to 100 days after RT for a subgroup of 16 patients treated with a total dose of 60 Gy given in 1.82 Gy per fraction. Results: Large radiation doses to subvolumes were associated with denser lung tissue measured with CT (p < 0.001). Opposed to this finding, the volume of lung tissue irradiated with significant doses (V40Gy) was negatively correlated with the average increase in lung tissue density (p = 0.003). Patients randomized to metoclopramide injections also experienced less increase in lung tissue density (p = 0.01). Conclusion: There was an increase in the density of irradiated lung tissue with radiation dose and time after RT. Metoclopramide and significant radiation doses to larger lung volumes (V40Gy) seemed to protect against fibrosis development