Patients were randomly assigned to receive either maintenance chemotherapy alone (15 patients) or a combination of stereotactic ablative radiotherapy (SAbR)—also known as stereotactic body radiation therapy or SBRT—to all sites of disease followed by maintenance chemotherapy (14 patients). Radiation to metastases was offered as a single fraction (to 21-27 Gray (Gy)), three fractions (to 26.5-33 Gy) or five fractions (to 30-37.5 Gy) of SAbR (regimens were biologically equivalent). Radiation to the primary disease site was delivered via SAbR where possible, or through 15 fractions of hypofractionated radiation therapy if the primary tumor was too central or involved mediastinal nodes. Maintenance chemotherapy was left to the discretion of the treating medical oncologists and consisted of pemetrexed, docetaxel, erlotinib or gemcitabine.

Twenty-nine patients were accrued between April 2014 and July 2016. The median patient age was 70 years (range 51-79 years) for the patients receiving maintenance chemotherapy only and 63.5 years (range 51-78) for the patients receiving SAbR to metastases followed by maintenance chemotherapy. Most patients were male (69%). Eighty-six percent of all patients had tumors with non-squamous histologies. Thirty-one lesions were treated with radiation in the 14 patients that received local therapy.


The median follow-up for this report was 9.6 months (range 2.4-30.2 months). Patient accrual was stopped ahead of schedule after an unplanned interim analysis found substantially improved survival rates in the arm receiving local therapy, matching similar findings in a parallel trial.

The interim analysis found a median progression-free survival rate of 9.7 months with consolidative radiation therapy followed by chemotherapy, versus 3.5 months for maintenance chemotherapy alone (p = 0.01; Hazard Ratio (HR) = 0.304, 95% CI 0.113-0.815). Survival rates were estimated using the Kaplan-Meier method and compared using the log-rank test and Cox proportional hazard models.

Specifically, rates of local control and delay in distant metastases also favored the approach incorporating radiation with systemic therapy. In the arm with consolidative local therapy, there were no recurrences in original sites of gross disease versus seven failures in original sites of gross disease in the arm receiving only maintenance therapy. At the time of analysis, 10 of the 15 patients receiving maintenance chemotherapy-only had progressed, compared with four of the 14 patients also receiving radiation. None of the recurrences among the latter patients were in areas treated directly with radiation therapy.

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