(P117) Outcomes, Patterns of Failures, and Toxicity for Patients Diagnosed With Pulmonary Metastases Treated With Stereotactic Body Ablative Radiotherapy (SABR)

Quynh-Nhu Nguyen, MD, William C. Chance, MD, Peter Balter, PhD, Jim Welsh, MD, Daniel Gomez, MD, Ritsuko Komaki, MD, Zhongxing Liao, MD, Joe Chang, MD, PhD, Reza J. Mehran, MD; UT MD Anderson Cancer Center

PURPOSE: To report patterns of failure, outcomes, and toxicity for patients with pulmonary metastases treated with stereotactic body ablative radiotherapy (SABR).

METHODS: From 2007 to 2014, a total of 49 patients with 61 pulmonary metastases were irradiated with SABR doses. Primary histology included: lung (n = 14), gastrointestinal (GI) (n = 15), sarcoma (n = 5), head/neck (n = 6), genitourinary (GU) (n = 3), melanoma (n = 3), endometrial (n = 2), and adrenal (n = 1). SABR doses were prescribed by tumor location and proximity to critical structures (central vs peripheral). The majority of metastases received 50 Gy in four fractions (n = 48), 70 Gy in 10 fractions (n = 3), 40 Gy in four fractions (n = 4), 50 Gy in five fractions (n = 1), or 45 Gy–60 Gy in 10 fractions (n = 5). Local failures were defined as recurrence within the high-dose region; locoregional failures included recurrences outside of the high-dose region, within the same lobe, or lymph nodes; and distant failures occurred in a separate lobe or outside of the thorax.

RESULTS: The 1-year and 2-year overall survival (OS) rates were 88% and 66%, respectively, with a median OS time of 29.1 months. The 1-year and 2-year progression-free survival (PFS) rates were 64% and 45%, respectively, with a median PFS time of 19.9 months. The 1-year and 2-year freedom from local failure rates were 94% and 84%, respectively. The 1-year and 2-year freedom from locoregional failure rates were 80% and 63%, respectively. The 1-year and 2-year distant metastases–free survival rates were 72% and 51%, respectively, with a median time to new distant metastases of 26.9 months. The toxicities included brachial plexopathy (grade 2, n = 2), radiation pneumonitis (grade 3, n = 1), and chest wall toxicity (grade 2, n = 7).

CONCLUSION: SABR is an effective treatment modality for patients with pulmonary metastases, with excellent local control. Further studies are warranted to elucidate which patients with pulmonary metastases would benefit from the local control with SABR and determine when to treat with systemic therapy due to quick progression of distant metastases.

Proceedings of the 97th Annual Meeting of the American Radium Society - americanradiumsociety.org