Clinical outcomes of image-guided proton therapy for histologically confirmed stage I non-small cell lung cancer

• Main Authors: Koichiro Nakajima, Hiromitsu Iwata, Hiroyuki Ogino, Yukiko Hattori, Shingo Hashimoto, Toshiyuki Toshito, Kensuke Hayashi, Kenji Akita, Fumiya Baba, Katsumi Nakamae, Jun-etsu Mizoe, Yuta Shibamoto
• Format: Article
• Language: English
• Published: BMC 2018-10-01
• Series: Radiation Oncology
• Subjects: Stage I non-small cell lung cancer; Proton therapy; Image-guided proton therapy; Fiducial metallic marker; Respiratory gating system
• Online Access: http://link.springer.com/article/10.1186/s13014-018-1144-5

Abstract Background Two prospective phase II trials were designed to assess the efficacy and safety of image-guided proton therapy (IGPT) for either medically inoperable or operable stage I non-small cell lung cancer (NSCLC). The present study reports the interim results of these trials. Methods Fifty-five patients with histologically confirmed stage I NSCLC (IA in 33 patients and IB in 22 patients; inoperable in 21 patients and operable in 34 patients) who received IGPT between July 2013 and February 2017 were analyzed. The median patient age was 71 years (range: 48–88 years). IGPT with fiducial metallic marker matching was performed for suitable patients, and a respiratory gating method for motion management was used for all treatments. Peripherally located tumors were treated with 66 Gy relative biological effectiveness equivalents (Gy(RBE)) in 10 fractions (n = 49) and centrally located tumors were treated with 72.6 Gy(RBE) in 22 fractions (n = 6). Treatment associated toxicities were evaluated using Common Toxicity Criteria for Adverse Events (v.4.0). Results Median follow-up was 35 months (range: 12–54 months) for survivors. For all patients, the 3-year overall survival, progression-free survival, and local control rates were 87% (95% confidence interval: 73–94%), 74% (58–85%), and 96% (83–99%), respectively. Fiducial marker matching was used in 39 patients (71%). Grade 2 toxicities observed were radiation pneumonitis in 5 patients (9%), rib fracture in 2 (4%), and chest wall pain in 5 (9%). There were no grade 3 or higher acute or late toxicities. Conclusions IGPT appears to be effective and well tolerated for all patients with stage I NSCLC. Trial registration Lung-001, 13–02-09 (9), registered 11 June 2013 and Lung-002, 13–02-10 (10), registered 11 June 2013.