Clinical Outcomes of Stereotactic Body Radiotherapy (SBRT) for Oligometastatic Patients with Lymph Node Metastases from Gynecological Cancers

Background: To evaluate clinical outcomes of stereotactic body radiation therapy (SBRT) as a local treatment for lymph node metastases from gynecological cancers. Methods: Between November 2007 and October 2021, we retrospectively analyzed 29 lymph node metastases in 22 oligometastatic/oligoprogressive patients treated with SBRT. The Kaplan-Meier method was used to estimate the rates survival. Univariate analysis for prognostic factors were performed with the log-rank test, and Cox proportional hazards regression was used to estimate hazard ratios (HR). Results: Median age was 62 years (IQR, 50-80 years). Median follow-up was 17 months (IQR 10.5-31 months). The median survival was 22 months (CI 95%: 4.2-39.7, IQR: 12.5-34.5 months). Six months, one year and two year overall survival (OS) were 96.6%, 85.2%, and 48.7%, respectively. Median local control (LC) was not reached. Six months, 1one year and 2 year were 93.1%, 87.9%, and 79.9%, respectively. Distant metastasis free survival (DMFS) at one year, and two year was 53% and 37.1%, respectively Four patients (18%) experienced acute G1-G2 toxicities. No G3-4 acute toxicity was reported, and no late toxicity was observed. Conclusions: SBRT for lymph node recurrence offers excellent in-field tumor control with safe profile and low toxicities. Size, number of oligometastases, and time primary tumor to RT seem to be significant prognostic factors.