Multi-institutional phase I/II trial of stereotactic body radiation therapy for lung metastases

To evaluate the efficacy and tolerability of high-dose stereotactic body radiation therapy (SBRT) for the treatment of patients with one to three lung metastases.

Patients with one to three lung metastases with cumulative maximum tumor diameter smaller than 7 cm were enrolled and treated on a multi-institutional phase I/II clinical trial in which they received SBRT delivered in 3 fractions. In phase I, the total dose was safely escalated from 48 to 60 Gy. The phase II dose was 60 Gy. The primary end point was local control. Lesions with at least 6 months of radiographic follow-up were considered assessable for local control. Secondary end points included toxicity and survival.

Thirty-eight patients with 63 lesions were enrolled and treated at three participating institutions. Seventy-one percent had received at least one prior systemic regimen for metastatic disease and 34% had received at least two prior regimens (range, zero to five). Two patients had local recurrence after prior surgical resection. There was no grade 4 toxicity. The incidence of any grade 3 toxicity was 8% (three of 38). Symptomatic pneumonitis occurred in one patient (2.6%). Fifty lesions were assessable for local control. Median follow-up for assessable lesions was 15.4 months (range, 6 to 48 months). The median gross tumor volume was 4.2 mL (range, 0.2 to 52.3 mL). Actuarial local control at one and two years after SBRT was 100% and 96%, respectively. Local progression occurred in one patient, 13 months after SBRT. Median survival was 19 months.

This multi-institutional phase I/II trial demonstrates that high-dose SBRT is safe and effective for the treatment of patients with one to three lung metastases.