Clinical Outcomes of Stereotactic Body Radiotherapy in Oligometastatic Gynecological Cancer

Abstract OBJECTIVE: The objective of this study was to assess the role of stereotactic body radiotherapy (SBRT) in the treatment of distantly recurrent, oligometastatic gynecological cancer. METHODS: The hospital records of 45 patients with F-fluorodeoxyglucose (F-FDG) positron emission tomography positive, distantly recurrent, oligometastatic gynecological cancer were reviewed. All these patients had a number of target lesions less than 5, with largest diameter less than 6 cm. The treatment was delivered with a TrueBeam LINAC and RapidArc technique, using 10 or 6 MV FFF beams. A total of 70 lesions were treated, and lymph nodes represented the most common site of metastases, followed by lung, liver, and soft tissues. Twenty lesions were treated with one single fraction of 24 Gy and 5 lesions received 27 Gy delivered in 3 fractions, depending on the ability to fulfill adequate target coverage and safe dose/volume constraints for the organ at risk with either regimen. RESULTS: Positron emission tomography scan 3 months after SBRT showed a complete response (CR) in 45 lesions (64.3%), a partial response in 14 (20.0%), a stable disease in 5 (7.1%), and a progressive disease in 6 (8.6%). No lesions in CR after SBRT subsequently progressed. Overall acute toxicity occurred in 13 (28.9%) patients. The most common grade 1 to 2 adverse event was pain (n = 9, 20.0%), followed by nausea and vomiting (n = 5, 11.1%). No grade 3 to 4 acute toxicities occurred, and no late toxicities were observed. Patients who failed to achieve a CR had a 2.37-fold higher risk of progression and a 3.60-fold higher risk of death compared with complete responders (P = 0.04 and P = 0.03, respectively). CONCLUSIONS: Stereotactic body radiotherapy offers an effective and safe approach for selected cases of oligometastatic gynecological cancer.