## 3 SBRT in Non-Ovarian Gynecologic Primary Oligometastases  
Most retrospective studies evaluating the role of SBRT in gynecologic malignancies included multiple primary histologies; although ovarian cancer was studied most, cervical, and uterine cancer were included as well [Table 1]. There are no trials to our knowledge with significant numbers of patients with vaginal or vulvar primary oligometastases or intracranial metastases, and thus will not be a focus of this review. [PERSON] et al. reported the outcomes of 40 patients with 60 extracranial oligometastases from gynecological cancers. Metastases were from ovarian cancer (43%), endometrial cancer (41%), cervical cancer (13%) and vaginal cancer (3%). Lymph node metastases were the most common site of radiation (55.5%) and most patients had a single lesion (65%). SBRT was delivered to a total median dose of 42 Gy (range, 24-70) and a median BED\({}_{10}\) of 72 Gy\({}_{10}\) (range, 48-180 Gy\({}_{10}\)). After a median follow-up 27 months, the median local control was 19 months, the 2-year local control rate was 100% and the 2-year progression-free survival was 23%. In a retrospective study by [PERSON] et al. [17], 29 patients with 35 oligometastatic cervical cancer (72%) and ovarian cancer (28%) were treated with SBRT for either de novo oligometastatic disease (24%) or oligoprogressive disease (76%). The 2-year local control was 85% and disease progression occurred at a median time of 7.7 months after SBRT. Complete response after SBRT was correlated with improved overall and progression-free survival. SBRT has been evaluated in primary oligometastatic cervical cancer in the recently published MITO RT2/RAD study [19] which represents the largest retrospective cohort of patients with oligometastases from primary cervical cancer treated with SBRT. A total of 83 patients with 125 oligometastatic cervical cancer lesions were treated with SBRT. Most patients had single (69.9%) pelvic (36.8%) lymph node (55.2%) disease treated to a total dose of 35 Gy in five fractions with a median BED\({}_{10}\) of 59.5 Gy. After a median follow-up of 14.5 months, complete response was noted in 58.4% of lesions and in 55.4% of patients. Interestingly, the authors noted significant improvements in local control, progression-free survival and overall survival in patients who had complete response (CR), as opposed to any other response (partial response (PR), stable disease (SD) or progression of disease (PD)). Two-year local control was 89% for CR and 22.1% for PR/SD/PD, respectively. Two-year progression-free survival was 42.5% for CR and 7.8% for PR/SD/PD, respectively. Two-year overall survival was 68.9% for CR and 44.4% for PR/SD/PD, respectively. However, no factors independently predicted for complete response. While the MITO RT1 study demonstrated the effectiveness and tolerability of SBRT for ovarian primary oligometastases, the MITO RT2/RAD study showed less favorable outcomes in cervical primary oligometastases treated with SBRT, but still suggested a promising avenue for further research in patients with comparatively unfavorable prognostic factors. In fact, early evidence in patients with cervical cancer with supraclavicular lymph node involvement without distant metastases showed that treatment with standard fractionation led to long term disease control which helped provide early rationale for selective targeting of oligometastatic disease with curative intent [23; 24; 25]. As for uterine cancer, most of the current data regarding uterine primary oligometastases are from retrospective studies with mixed cohorts [26; 27; 21; 22; 28; 29; 30]. The only recent study to our knowledge that exclusively included uterine primary oligometastases treated with SBRT is a single-institution retrospective analysis including 27 patients with 61 biopsy-proven lesions [20]. Most patients (74%) were treated for oligorecurrence and half (51.9%) had adenocarcinoma.