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The use of stereotactic radiotherapy (SBRT) for oligometastases is supported by several literature studies, but in the setting of gynecological tumors, this scenario remains unexplored. This study reports a preliminary assestement of clinical outcomes in a cohort of 46 patients (pts) with oligometastatic gynaecological cancers.

From 4/2009 to 5/2021, 85 lesions in 46 pts were treated with SBRT. Five lesions of 4 pts were treated with Image Guided-helical Intensity Modulated Radiotherapy (IG-IMRT) to a median dose of 54 (35-63) Gy in 6 (5-10) median fractions prescribed at 95% of the Planning Target Volume (PTV). Eighty lesions of 42 pts were treated with robotic SBRT to a median dose of 40 (18-60) Gy in a median of 5 (1-8) fractions, prescribed at a median isodose of 80% (68-84%). Nine PTVs (10.6%) were in the same field of previous adjuvant or salvage radiotherapy performed with IG-IMRT with a median dose of 50.4 Gy. Primary histology was: uterine in 42%, ovarian in 33%, cervical in 15.3% and other (fallopian tubes, vulva and vagina) in 9.4 % of lesions, respectively. Target locations were 53.7% lymph nodes, 33% lung, 6% bone, 6% central nervous system and 3.5% liver. Gross tumor volume was defined by the fusion of CT, PET/CT and/or MRI images. Toxicity was assessed using CTCAE version 4.03 criteria.

The median age of the cohort at the treatment was 67 years (33-91). Median follow-up was 18 months (0.69–75.4). Eleven pts (24%) presented grade (G) 1-2 acute toxicity. No grade ≥3 acute toxicity was observed. Two pts presented late toxicity: one had G2 rib pain persistent 28 months after the end of the treatment, and the other, irradiated on D12 (lytic lesion), a spine fracture 12 months later, with G3 bilateral leg pain and motor deficit, and underwent surgical decompression. After treatment 74% of targets had a complete response, 14% a partial response and 12% a progression disease. Overall survival (OS) at 6 and 12 months after the treatment was 87 % and 70 %, respectively. Twelve-months local relapse-free survival was  89.7 % (Fig.1). Systemic progression occurred in 67% of pts with a progression free-survival (PFS) of 5.6 months (0.56-67.2).

Our mono-institutional experience supports the use of SBRT in the management of the oligometastatic gynaecological cancer, with acceptable toxicity and promising results in terms of local control. Distant progression remains the primary site of failure in these pts, and this confirm the need for further research of effective salvage systemic therapy.