Clinical efficacy and prognosis of stereotactic body radiation therapy for pulmonary oligometastases

Abstract

Objective To analyze the clinical efficacy and prognosis of stereotactic body radiation therapy (SBRT) for pulmonary oligometastases. Methods Medical records of 104 patients with SBRT for pulmonary oligometastases in our hospital between 2012 and 2018 were retrospectively reviewed. SBRT was performed by intensity modulated radiation therapy (IMRT) technique before December 2015, and by helical tomotherapy (HT) technique in others. The local control (LC), progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method. Cox-regression was used for univariate analyses and multivariate analyses. The radiotherapy-related adverse events were evaluated by NCICTCAE V4.0. Results The 1-, 2- and 3-year LC rates were 86.6%, 75.9% and 72.3%, respectively. The 1-, 2- and 3-year PFS rates were 40.9%, 28.4% and 22.1%, respectively. The 1-, 2- and 3-year OS rates were 75.9%, 53.2% and 43.53%, respectively. The median OS time was 26.6 months. Multivariate analyses showed that the pathologic type of primary tumor, the volume of lung oligometastases and the carcino-embryonic antigen (CEA) level before SBRT were the independent prognostic factors of LC (χ2=28.66, P<0.05). The way of tumor progression after SBRT was the independent prognostic factor of OS (χ2=40.01, P<0.05). Meanwhile, there were no significant differences in the LC and OS between HT-SBRT and IMRT-SBRT. Radiation pneumonitis was the major adverse event of SBRT (n=25, 24.04%). Less than 7% patients experienced grade 2 and above radiation pneumonitis. Conclusions SBRT shows high local control rates and tolerable adverse events in the treatment of pulmonary oligometastases. There were no significant differences in the clinical efficacy and adverse events between HT-SBRT and IMRT-SBRT, which means they are all suitable for clinical application. Key words: Pulmonary oligometastases; Stereotactic body radiation therapy; Treatment outcome; Prognosis