SBRT for elderly oligometastatic patients as a feasible, safe and effective treatment opportunity

The constantly increasing life expectancy is raising the issue of treating oncological older patients, who were traditionally candidates to best supportive care or palliative treatments. Several literature data support SBRT in the treatment of the oligometastatic patient as a potentially curable therapeutic option. However, data on older patients are lacking. This study presents the outcomes of a cohort of 61 oligometastatic patients over the age of 80 years who received SBRT, that was proposed to all patients with a minimum Karnofsky Performance Status ≥ 70 and a life expectancy of at least 6 months, with up to five oligometastatic lesions. Radiotherapy was delivered in 3-10 fractions with VMAT-IGRT technique. Toxicity was retrospectively collected according to CTCAE v4.0. Data were retrospectively collected and analyzed. Univariate and multivariate analysis were performed for assessing any potential predictive factor for clinical outcomes. A total of 90 oligometastases were treated in 61 patients with median age 82 years (range, 80-90). The most frequent histology was colorectal cancer (27% of cases). Median follow-up was 20 months (range, 2-63). Local control rates at 1- and 2-years were 98.8% and 88.2%, with colorectal histology being associated with worse LC rates (p = 0.014) at univariate analysis. Progression-free survival rates at 1- and 2-years were 48.6% and 30.5%. Oligorecurrent lesions and single oligometastases were associated with better PFS rates (respectively, p = 0.04 and p = 0.011). Overall survival rates were 75% and 60.5%, polymetastatic spread being predictive of worse survival outcomes at multivariate analysis (p = 0.012). No G2 or higher adverse events were recorded. Our study supports the role of SBRT for the treatment of elderly oligometastatic patients, highlighting the possibility to further explore this therapeutic option in the management of older oncological patients.