Clinical efficacy of stereotactic ablative radiotherapy for lung metastases arising from colorectal cancer

Background: Limited data describe the prognosis after stereotactic ablative radiotherapy for lung metastases arising from colorectal cancer. Thus, we evaluated treatment outcomes of stereotactic ablative radiotherapy for those patients. Methods: The study involved patients received stereotactic ablative radiotherapy for one to three lung metastases arising from colorectal cancer at a single institution. A total dose of 40-60 Gy (median, 48 Gy) in three or four fractions was prescribed. Results: A total of 79 metastatic lung lesions from 50 patients who underwent curative resection for their primary colorectal cancer or salvage treatment at a recurrent site were included. The one-and three-year local control rates were 88.7 % and 70.6 %, respectively. The three-year overall survival and progression-free survival rates were 64.0 % and 24.0 %, respectively. Patients with tumor volume <= 1.5 mL had a significantly better overall survival rate than those with tumor volume > 1.5 mL (68.0 % vs. 60.0 % at three-year, p = 0.02). Local control was associated with a trend towards better survival (p = 0.06). No pulmonary complications greater than grade 2 were observed. Conclusion: Stereotactic ablative radiotherapy is a competitive treatment modality for the management of lung metastases arising from colorectal cancer.