DOSIMETRIC EVALUATION OF THE IMPACT OF ACTIVE BREATHING CONTROL (ABC) SYSTEM ON PHYSICAL LUNG DOSE-VOLUME PARAMETERS IN PATIENTS RECEIVING CONSOLIDATIVE RADIATION THERAPY (RT) FOR EXTENSIVE STAGE SMALL CELL LUNG CANCER (ES-SCLC)

Target determination for hepatic tumors

Abstract

Patients with extensive stage small cell lung cancer (ES-SCLC) suffer from impaired pulmonary functions due to their disease burden and avoidance of radiation therapy (RT) related pulmonary toxicity is of utmost importance. Within this context, efforts have been focused on improving the toxicity profile of radiation delivery by incorporating of contemporary RT techniques. Active Breathing Control (ABC) system has been developed for the management of respiratory motion in thoracoabdominal tumors by achieving reproducible breath holds. In this study, we evaluate the impact of the ABC system on physical lung dose-volume parameters (DVH) in patients receiving consolidative RT for ES-SCLC. For 16 patients referred to our clinic, two different RT plans with and without the ABC system were created and the mean lung dose (MLD) and V20 were analyzed.  MLD and V20 were 2267 cGy and 36.7%, respectively at free breathing. MLD and V20 were 1882 cGy and 28.5%, respectively incorporation of the ABC system. The inclusion of the ABC system in consolidative thoracic RT therapy resulted in a 16.98% and 22.34% reduction in MLD and V20, respectively. For the radiotherapeutic management of ES-SCLC, the ABC system is considered to contribute to the treatment.