Treatment of multiple primary lung cancers using stereotactic radiotherapy, either with or without surgery.

BACKGROUND AND PURPOSE Multiple primary lung cancers (MPLC) are not an uncommon presentation. Current guidelines recommend a curative approach when early-stage MPLC is diagnosed as favorable outcomes have been reported after surgery. We studied outcomes following stereotactic ablative radiotherapy (SABR). MATERIALS AND METHODS Following review of imaging and pathology at a multi-disciplinary tumor board, a total of 62 patients were referred for SABR with a diagnosis of synchronous MPLC. SABR was performed for both lesions in 56 patients, while another 6 underwent SABR for only one lesion and surgery for the other lesion. A total dose of 54-60 Gy was delivered in 3-8 fractions. RESULTS Median follow-up was 44 months (95% CI: 29-59). Overall survival of all patients was 31 months (95% CI: 17-44), with an actuarial 2-year survival of 56%. No grade 4 or 5 post-SABR toxicity was observed. Local control rates calculated per lesion, were 84% at 2 years, and 78% at 3 years. The two-year actuarial regional control rate was 87%. CONCLUSIONS SABR for synchronous MPLC achieves a lesion control rate of 84% after 2 years, with limited toxicity. SABR should be considered when patients with lung cancer present with a synchronous second lesion and no nodal involvement.