Oligometastatic cancer in elderly patients: the "blitzkrieg" radiotherapy approach : SBRT in oligometastatic elderly patients.

Aims: To retrospectively evaluate the outcome of stereotactic body radiation therapy (SBRT) in the treatment of elderly patients affected by isolated body metastasis from different primitive tumors.

Methods: 70 patients with isolated body metastasis were treated. Median age at diagnosis was 75 years (IQR 69-80). The most common SBRT fractionation scheme was 5 × 7 Gy (total dose 35 Gy). The primary endpoints were Local Control (LC) and Toxicity. Secondary endpoints were Overall Survival (OS) and Disease-Specific Survival (DSS). Response to radiotherapy was assessed according to RECIST criteria v1.1. Toxicity was registered according to Common Terminology Criteria for Adverse Events (CTCAE) v 4.0. We performed survival analysis with the Kaplan-Meier method. The correlation between time actuarial incidence and clinical parameters was studied.

Results: Median follow-up was 26.5 months. 44 patients (62.8%) were alive at the time of analysis, while 22 (31.4%) died because of the disease. Local control at 2 and 3 years was 87%. The 2-year OS and DSS were 84 and 71%, respectively, while the 3-year values were 57 and 62%. PFS at 2 and 3 years was 41 and 25%, respectively. On univariate analysis, KPS ≥ 90 is statistically correlated with improved OS and DSS (p < 0.05). Acute toxicity of grade ≥ 2 occurred in 4 (5.7%) patients, while late toxicity ≥ 2 was recorded in 6 (8.6%) patients.

Conclusions: Ablative Radiotherapy represents a safe, effective, and minimally invasive treatment modality for elderly oligometastatic patients who are judged unfit for systemic therapy.