Proton beam therapy is a safe and feasible treatment for patients with second primary lung cancer after lung resection. - Ono, Takashi; Nakamura, Tatsuya; Azami, Yusuke; Suzuki, Motohisa; Wada, Hitoshi; Kikuchi, Yasuhiro; Murakami, Masao; Nemoto, Kenji (Thoracic Cancer, 2019)