ESTRO 2022 - Abstract Book

S623

Abstract book

ESTRO 2022

Most patients (834, 71.2%) had a further distant progression. DMFS at 1, 2 and 3 years was 59.5%, 44.7% and 40.1%, respectively. Among progressing patients, the majority (598, 71.6%) experienced a further oligometastatic progression. In 347 patients (41.6%) the new metastases appeared in the same organ of the irradiated lesion(s), in 341 (40.8%) in a different organ, while in 147 (17.6%) progression occurred both in the same and in at least one different organ. Considering both local and distant progression, PFS at 1, 2 and 3 years was 57.2%, 43.4% and 39.4%. During follow up, 512 (43.7%) patients died for disease progression, 55 (4.7%) died for other causes not related to cancer. Among living patients, 159 (13.6%) remained free from disease progression, 78 (6.7%) were still affected by active residual disease in irradiated sites and 367 (31.3%) experienced were alive with further metastatic disease. OS at 1,2 and 3 years was 86.6%, 65.4% and 50.3%, respectively. KM curves are shown in figure 1. At univariate analysis, age, primary tumor site, disease free interval, PS, previous systemic therapies, number of irradiated metastases, site of irradiated metastases and BED resulted statistically significant for OS with a p value < 0,05. Primary tumor site, disease free interval, PS, previous systemic therapies, number of irradiated metastases, site of irradiated metastases and BED had a statistically significant correlation with PFS. Conclusion SRT for oligometastatic patients is a valid treatment, with potential for long term remission. In a large database analysis, half of patients is still alive after 3 years. A better integration with effective systemic therapies could reduce the occurrence of distant progression, which remains the main pattern of failure.

MO-0713 Stereotactic Body Radiotherapy for Long Bone Metastases: An International Multicenter Analysis