2356 - Contemporary Experience with Percutaneous High Dose Rate (HDR) Brachyablation for Malignant Lung Tumors
Presenter(s)
M. A. Eala1, D. Moghanaki1, J. Phan1, T. Oughourlian1, J. Charters1, R. Suh2, F. Abtin2, S. Genshaft2, M. A. Hagio1, S. J. Park1, P. S. Venkat1, A. J. Chang1, and A. Lee1; 1Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, 2Department of Radiological Sciences, University of California, Los Angeles, Los Angeles, CA
Purpose/Objective(s): High dose rate (HDR) brachyablation has been used at our institution since 2015 to treat difficult primary and metastatic malignant lung tumors in patients who are not ideal candidates for surgery, external beam radiation therapy, or image-guided thermal ablation. Herein we provide a contemporary summary of our experience with this unique treatment modality.
Materials/Methods: We reviewed our experience from October 2019 to February 2022, identifying 33 patients with 41 lung tumors treated with CT-guided percutaneous brachyablation performed by a multidisciplinary team of interventional radiology and radiation oncology specialists. The median dose delivered was 24 Gy (range: 12-27 Gy) in a single fraction to 39 tumors, while two tumors were treated with a median dose of 43.5 Gy (range: 39-48 Gy) over two fractions 2-4 weeks apart. Response Evaluation Criteria in Solid Tumors (RECIST 1.1) was used to evaluate tumor control. Acute (<90 days) and late (>90 days) treatment-related toxicities were graded according to Common Terminology Criteria for Adverse Events v5.0.
Results: Median age at the time of treatment was 65 years (range: 40-86), with 55% male and 45% female. Most patients (88%) had good performance status (ECOG 0-1). Among the 41 treated malignant tumors, 80% were metastatic, and 20% were primary lung tumors. Tumor locations included peripheral (31.7%), central (34.1%), and ultra-central (34.1%). Median tumor size was 3.5 cm (range: 0.6-12.9 cm), and the median tumor volume was 9.0 cc (range: 0.05-150.8 cc). Dosimetric analyses revealed a mean tumor dose of 68.6 Gy (SD 18), while the mean CTV V150% and V200% were 76.0% (SD 12.2) and 58.7% (SD 12.9), respectively. The mean D95 was 102.1% (SD 20.5). The mean ipsilateral lung dose was 2.3 Gy (SD 1.9). With a median follow-up duration of 22 months, the local control rate was 98%, with only one tumor progressing at the treatment site at almost 20 months post-treatment. Acute toxicities occurred in only one patient requiring chest tube placement post-procedure and experiencing acute grade 3 toxicity. No late grade 3-4 toxicities were observed in the cohort.
Conclusion: The safety of percutaneous HDR brachyablation has established it as a standard of care treatment option at our institution, providing a highly effective treatment for difficult lung tumors. Acute and late toxicities were minimal. The local control rate of 98% exceeds what is generally reported after stereotactic body radiation therapy (SBRT), justifying its further evaluation for patients with primary or metastatic malignant lung tumors otherwise eligible for SBRT, thermal ablation, or surgery.