Role of stereotactic body radiation therapy for lung metastases from radio-resistant primary tumours

A retrospective analysis was performed on patients treated for lung oligo-metastatic disease from radio-resistant histology groups. The primary end point was local control (LC), secondary end points were overall survival (OS) and progression free survival (PFS). Toxicity was scored according to CTCAE 4.03. 200 patients were analyzed: 49.5% of the cases derived from colorectal primary tumors, 20.5% from sarcomas, 12.0% from renal cell carcinoma and the rest from other mixed origin. The mean follow-up was 24.2 months. LC at 1 and 2 years was 91, 84.9%. Primary histology and the presence of extra-pulmonary disease had a significant impact on LC. OS at 1 and 2 years was 88.7, 65.4%. Primary histology, disease free interval, presence of extra-pulmonary disease, number of irradiated lung lesions and age showed a correlation with prognosis at univariate analysis. PFS at 1 and 2 years was 84, 57.7%. The presence of extra-pulmonary disease and the number of irradiated lung lesions correlated with prognosis. Treatment was well tolerated with no G3-4 acute or late toxicity recorded. Colorectal metastases showed a higher rate of local relapse. However, the factors mostly influencing prognosis were the presence of extra-pulmonary disease and the number of lung lesions.