DTPA clearance test: a sensitive method for detecting radiation-induced lung fibrosis in lung cancer patients

The aim of this study is to analyze the frequency of lung injury and the sensitivity of the diethylenetriamine penta-acetic acid (DTPA) clearance test in detecting lung injury in patients undergoing radiotherapy (RT) to the thorax.

Twenty individuals scheduled for RT for lung cancer were included as the patient group. The healthy control group consisted of 20 age and gender-matched individuals who were nonsmokers with no history of comorbidities. We conducted follow-up with patients at 0-1-6 months, performing carbon monoxide diffusion test (DLCO), DTPA clearance test (excluding the first month), and high-resolution computed tomography of the thorax. The control group was followed up with DLCO between the baseline and 6th months.

Ninety percent of the patient group was male, and the median age was 62 years. Seventy percent of the patients had squamous cell carcinoma and adenocarcinoma. Pneumonitis was detected in the patient group in the first month (100%) and fibrosis in the sixth month (%100) Both at the beginning and in the sixth month, the DLCO values of patients who received RT were lower than those of the control group ( P  = 0.001 and P  < 0.001, respectively). While DTPA clearance was similar between irradiated and non-radiated lungs at the beginning, there was a substantial decrease in the irradiated lung in the sixth month( P  = 0.001). There was no significant correlation between malignancy type, RT dose, and tumor size( P  > 0.05).

The DTPA clearance test could be an alternative method for demonstrating radiation injury in patients receiving RT.