Clinical outcomes following image-guided stereotactic body radiation for pulmonary oligometastases.

Acknowledgement and Funding: This work was made possible by funding from NIH grant T32 RR023254; Salary support for Dr M.M. Fuster was provided by the Department of Veterans Affairs (BLR&D CDTA Career Development Award).
Keywords: Pulmonary metastases; oligometastases; stereotactic body radiotherapy (SBRT); frameless SBRT.
Background: Lung is a common site of extracranial metastases. Frameless Stereotactic Body Radiation Therapy (SBRT) is a promising new therapy for unresectable neoplastic lung lesions used at our institution.
Methods: A retrospective study of 21 patients and 33 lesions treated with SBRT was done. Local control (LC), distant control (DC), progression-free survival (PFS) and overall survival (OS) were analyzed using the Kaplan-Meier method. Potential prognostic factors were analyzed using the log-rank test and Cox regression. Toxicities were also reported.
Results: Actuarial local control rates by lesions were 88% (95% confidence interval [CI], 77-99%) and 76% (95% CI, 59-92%) at 12-and 24-months, respectively. Actuarial local control rates by patients was 80% (95% CI, 62-98%) and 71% (95% CI, 43-100%) for 12- and 24-months, respectively. DC rates were 52% (95% CI 31-74%) and 38% (95% CI, 15-61%), at 12- and 24-months respectively. PFS rates were 52% (95% CI 31-74%) and 32% (95% CI 9-55%) at 12- and 24-months, respectively. Overall survival rates were 90% (95% CI 77-100%) and 78% (95% CI 59-97%) at 12- and 24-months, respectively. Single metastasis was associated with better PFS (p=0.023). No toxicities greater than CTCAE grade 3 were observed.
Conclusions: Frameless SBRT achieves acceptable control in pulmonary metastatic lesions with an excellent toxicity profile.