Jae Myoung Noh

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is associated with fatal complications after radiotherapy (RT) for lung cancer patients; however, the role of proton therapy to reduce the incidence of life-threatening complications is unclear. Herein, we present the preliminary results of early-stage lung cancer patients having IPF and treated with RT, with a focus on the comparison between X-ray and proton therapy. METHODS: From January 2010 to October 2017, we retrospectively reviewed the medical records of 264 patients with stage I-II non-small cell lung cancer (NSCLC) treated with definitive RT alone. Ultimately, 30 patients (11.4%) who had underlying IPF were analyzed. Among these, X-ray and proton RT were delivered to 22 and 8 patients, respectively. Treatment-related complications and survival outcomes were compared between X-ray and proton therapy. RESULTS: The median follow-up duration was 11 months (range, 2 to 51 months). All living patients were followed-up at least 9 months. Treatment-related death occurred in four patients (18.2%) treated with X-ray but none with proton therapy. Most patients died within one month after the onset of pulmonary symptoms in spite of aggressive treatment. In addition, the 1-year overall survival (OS) rate in patients treated with X-ray and proton was 46.4 and 66.7%, respectively, and patients treated with proton therapy showed a tendency of better survival compared to X-ray (p = 0.081). Especially, in GAP stage II and III subgroups, patients treated with proton therapy showed significantly increased survival outcomes compared to X-ray (1-year OS rate; 50.0% versus 26.4%, p = 0.036) in univariate analysis. CONCLUSIONS: RT is associated with serious treatment-related complications in patients with IPF. Proton therapy may be helpful to reduce these acute and fatal complications. TRIAL REGISTRATION: retrospectively registered.

Tumor microenvironments polarize neutrophils to protumoral phenotypes. Here, we demonstrate that the angiotensin converting enzyme inhibitors (ACEis) and angiotensin II type 1 receptor (AGTR1) antagonist attenuate tumor growth via polarization of neutrophils toward an antitumoral phenotype. The ACEis or AGTR1 antagonist enhanced hypersegmentation of human neutrophils and increased neutrophil cytotoxicity against tumor cells. This neutrophil hypersegmentation was dependent on the mTOR pathway. In a murine tumor model, ACEis and AGTR1 antagonist attenuated tumor growth and enhanced neutrophil hypersegmentation. ACEis inhibited tumor-induced polarization of neutrophils to a protumoral phenotype. Neutrophil depletion reduced the antitumor effect of ACEi. Together, these data suggest that the modulation of Ang II pathway attenuates tumor growth via polarization of neutrophils to an antitumoral phenotype.