Stereotactic body radiotherapy for pulmonary oligometastases: A monoinstitutional analysis of clinical outcomes and potential prognostic factors.

Purpose: We report the retrospective data of a cohort of patients who received stereotactic body radiotherapy for pulmonary oligometastases aiming to assess the clinical factors potentially affecting the clinical outcomes. Methods: The present series reports the outcomes of a cohort of 71 patients with pulmonary oligometastases. All patients were treated with SBRT performed with VMATIGRT, up to 5 secondary lesions. Survival estimates were performed using Kaplan-Meier method. Results: A total of 98 lesions in 71 patients were treated from February 2014 to August 2020. The most frequent histologies were: colo-rectal in 37.7%, lung cancer in 44.8%, head and neck cancer in 8.1%, other in 9.4%. Median age was 71 (range, 32-93 years). Concurrent systemic therapy was administered in 32.3%. SBRT was delivered for a median total dose of 60 Gy (range, 55-70 Gy) in 3-10 fractions for a median BED10=105 Gy (range, 96-180 Gy). Median follow-up was 29.5 months (range, 6-81), with no acute or late G>2 adverse event. Our LC rates at 2 and 4-years were 92.4% and 89.8%. DPFS rates at 2- and 4- years were 45.3% and 27.2%. A second SBRT course was proposed in 21 cases (29.5%) who developed an oligoprogression, resulting in median time to second progression of 9 months (range, 2-44) and 2-year PFS2 rate of 42.4%. At univariate analysis, patients with sequential oligometastases reported better OS rates (p=0.002), also confirmed at multivariate analysis, where also distant progression related with worse OS (p=0.022). Higher local control rates relate to better PFS (p=0.04). The 2- and 4- OS rates were 61% and 39.7% Conclusions: SBRT is feasible for pulmonary oligometastases with favorable outcomes and toxicity. At multivariate analysis, patients with sequential oligometastatic progression maintain a survival advantage. Also, local control was found to be related to improved PFS rates. [ABSTRACT FROM AUTHOR]