Effect of I-125 Seed Implantation on Lung Cancer and Its Environmental Impact

ABSTRACT: This paper compares the efficacy and adverse effects of iodine-125 ( 125 I) seed implantation and external beam radiotherapy (EBRT) in the treatment of lung cancer as well as impact of the 125 I radiation on the environment around the patients. A total of 40 patients who were admitted with lung cancer to our hospital from October 2017 to October 2018 were enrolled into this study. The patients were randomly assigned into study groups treated with 125 I seed implantation (20 patients) and a control group treated with EBRT (20 patients). The patients were followed up for 6 mo by CT scanning of the tumor size as well as measuring serum carcinoembryonic antigen (CEA), cytokeratin fragment (CYRA21-1), and neurospecific enolase (NSE) levels. The dose rate of 125 I at various distances and times after implantation was also measured. The local tumor control rate was higher in the study group than in the control group. CEA, NSE and CYFRA21-1 significantly decreased from the pre-treatment baseline in both groups (p < 0.05). Side effects of pneumothorax, hemoptysis, chest pain, and leukopenia occurred in the patients treated with 125 I seed implantation. Radiation of the 125 I isotope, which was correlated with the number of implanted 125 I seeds, decreased rapidly in a time- and distance-dependent manner. A lead apron could significantly block radiation of 125 I. Compared to EBRT, brachytherapy with 125 I seed implantation in the lung cancer had a better therapeutic outcome with fewer complications. A lead apron could protect members of patient's family as well as public from 125 I radiation.