Observation on the Clinical Effect of Stereotactic Body Radiotherapy in Patients with Oligometastatic Tumors

Objective: To observe the efficacy and safety of stereotactic body radiotherapy (SBRT) in the treatment of extracranial oligometastases. Method: A retrospective analysis of 70 patients with extracranial oligometastasis of malignant tumors who underwent SBRT in our hospital (Shaanxi Provincial People’s Hospital) from January 2019 to December 2021 with ? 5 metastases, ?3 metastatic organs, and metastases with diameters of ? 5 cm. According to the clinical data of patients, the dose-fractionation mode of SBRT is mainly determined according to the pathology of the primary tumor, the location of the metastatic tumor, and the important structures around the tumor. The local control, survival and adverse reactions were observed. Results: A total of 219 oligometastatic lesions in 70 patients were treated with SBRT. The median follow-up time was 24 months (12–40 months). The local control rate (LCR) of all target lesions assessed 3 months after radiotherapy was 94.1%; the 1-, 2-, and 3-year LCRs were 88.6%, 74.6%, and 64.9%, respectively. The median progression-free survival (PFS) was 11.8 months (95% CI, 8.9–14.7 months), and the 1- and 2-year PFS rates were 48.6% and 32.6%, respectively; the median overall survival (OS) was 31.9 month (95% CI 26.0-37.8 months), the 1-year OS rate was 84.3%. The local control time, PFS, and OS of patients with metastases ? 3 cm were significantly better than those with metastases > 3 cm, and the differences were statistically significant (P < 0.05). Acute adverse reactions after SBRT treatment in oligometastatic patients were mainly bone marrow suppression and gastrointestinal reactions, with incidence rates of 48.98% and 30.61%, respectively; chronic adverse reactions were mainly pain (bone, muscle), radiation enteritis, and radiation pneumonitis, with incidence rates of 38.57%, 30.00%, and 24.29%, respectively. The treatment-related adverse reactions were mainly grade 1, which were all improved after symptomatic treatment, except for one patient with bone metastases from lung cancer who had grade 4 myelosuppression. No grade 4 or 5 adverse events occurred in the other patients. Conclusion: The application of SBRT in the treatment of extracranial oligometastases is safe, effective, and has high tolerability.