Hi, my name is Stephanie Newton. Today, I will be reporting the outcomes with multidisciplinary management of central lung tumors treated with percutaneous high-dose rate brachytherapy. I have no conflicts of interest to disclose. Centrally located lung tumors present treatment challenges given their proximity to critical airways and medial stymal structures, such as the trachea, main stem bronchi, esophagus, and at the heart. Therapeutic options may be limited for medically inoperable patients, particularly if they receive previous thoracic radiation therapy. We therefore introduce percutaneous high-dose rate brachytherapy to improve the therapeutic ratio for patients with central lung tumors. This report summarizes long-term safety and efficacy outcomes. The first 25 patients with 37 lung tumors were treated from September 2015 to August 2019 with percutaneous high-dose rate brachytherapy. Treatments were delivered by a multidisciplinary team of interventional radiologists, pulmonologists, and radiation oncologists. 23 patients received a median dose of 21.5 gray, ranging from 15 to 27.5 gray in a single fraction to the surface of the clinical target volume. Two patients received a median dose of 24.75 gray, ranging from 24 to 25.5 gray over two three fractions. Here in figure 1a, an ultracentral tumor was treated with percutaneous high-dose rate brachytherapy to 24 gray in a single fraction. Here in figure 1b, the isotopes curves from another percutaneous high-dose rate brachytherapy treatment are displayed. In this case, the target was treated to 25 gray in a single fraction. The thick red line displays the clinical target volume contour, while the dark blue line displays 100% isotopes line. Tumor local control was evaluated by response evaluation criteria in solid tumors version 1.1, while treatment-related toxicities were graded by common terminology criteria for adverse events version 5. Any events occurring within 90 days were defined as acute, while those occurring after were considered late. Local control and overall survival rates were estimated by the Kaplan-Meyer method. Among the 37 treated tumors, 88% of them were metastatic. 24.3% of the tumors were centrally and 54% of the tumors were ultracentrally located. The average tumor volume was 11.6 cubic centimeters, ranging from 0.57 to 62.8. Figure 2 shows the resolution of an ultracentral pulmonary metastasis in a patient with metastatic hepatocellular carcinoma. It shows the appearance of the tumor before treatment and at the time of CT-guided percutaneous high-dose rate brachytherapy, as well as the near-complete resolution on CT scan four months post-treatment. The median follow-up was 19 months, ranging from 3 to 48 months. The two-year local control and overall survival rates were 96.2% and 65.5% respectively. Four patients experienced acute grade 1 to 2 toxicity, and the study did not identify patients with a late toxicity beyond 90 days follow-up. Therefore, percutaneous high-dose rate brachytherapy is a promising therapeutic option for centrally located primary and metastatic lung tumors. Future comparisons to more established therapies, such as stereotactic body radiotherapy and other ablative techniques, are warranted to expand multidisciplinary management options.

percutaneous high-dose rate brachytherapy

centrally located lung tumors

treatment outcomes

local control rates

overall survival rates