Introduction/Background Stereotactic Ablative Body Radiotherapy (SABR) is emerging as a treatment option for patients with oligometastatic solid tumours. The primary aim of this approach is to prolong disease free survival and delay the initiation of systemic therapies. We report a single institution clinical outcomes.

Methodology 71 lesions from 51 patients with relapsed oligometastatic (1 -3 lesions) gynaecological cancers (endometrium = 23, ovary = 16, cervical = 10, vulva = 1 and Vagina = 1) were treated with SABR, delivered using both cyberknife and VMAT. Treatment was delivered using a median of 4 fractions to a median dose of 45 Gy. Response was assessed with repeat imaging 10 – 12 weeks post-SABR. CTCAE system version 5.0 was used to assess acute and late toxicity.

Results Mean age was 67 years. Target lesions were pelvic node = 22, para-aortic node = 18, lung = 16, liver = 4, brain = 3, peritoneal mass = 2, porta-hepatis node = 2, bone =2, right adnexa = 1, vaginal vault = 1. After a median follow-up of 17 months, 48% of the lesions had a partial response (PR), 12% had a complete response (CR), 26.5% were stable (SD), and 13.5% has progressive disease. Lesions greater than 30 mm had unfavourable outcome. Median progression free survival (PFS) was 11.2 months. Median survival (OS) has not been reached. Treatment was generally well tolerated, 2 patients experienced grade 3 toxicity.

Conclusion SABR for patients with relapsed oligometastatic gynaecological cancers is a safe treatment with promising results in terms of local control and PFS. As distant progression remains the primary mode of failure in these patients, the combination of SABR and systemic therapies requires evaluation in randomized controlled trials.