@article{oai:repo.qst.go.jp:00046766,
 author = {Takahashi, Wataru and Nakajima, Mio and Yamamoto, Naoyoshi and Yamada, Shigeru and Yamashita, Hideomi and Nakagawa, Keiichi and Tsuji, Hiroshi and Kamada, Tadashi and 高橋 渉 and 中嶋 美緒 and 山本 直敬 and 山田 滋 and 辻 比呂志 and 鎌田 正},
 journal = {Radiation oncology (London, England)},
 month = {Apr},
 note = {Background
The purpose of this study was to evaluate the efficacy and feasibility of carbon ion radiotherapy (CIRT) for oligo-recurrent lung tumors from colorectal cancer (CRC). 
\nMethods
From May 1997 to October 2012, 34 consecutive patients with oligo-recurrent pulmonary metastases from CRC were treated with CIRT. The patients were not surgical candidates for medical reasons or patient refusal. Using a respiratory-gated technique, carbon ion therapy was delivered with curative intent using 4 coplanar beam angles. A median dose of 60 GyE (range, 44–64.8 GyE) was delivered to the planning target volume (PTV), with a median daily dose of 15 GyE (range, 3.6–44 GyE). Treatment outcome was analyzed in terms of local control rate (LCR), survival rate, and treatment-related complications. 
\nResults
In total, 34 patients with 44 oligo-recurrent pulmonary lesions were treated with CIRT. Median follow-up period was 23.7 months. The 2- and 3-year actuarial LCRs of the treated patients were 85.4% ± 6.2% and 85.4% ± 6.2%, respectively. Overall survival was 65.1% ± 9.5% at 2 years, and 50.1% ± 10.5% at 3 years. Although survival rates were relatively worse in the subsets of patients aged < 63 years or with early metastasis (< 36 months after resection of primary site), these factors were not significantly correlated with overall survival (P = 0.13 and 0.19, respectively). All treatment-related complications were self-limited, without any grade 3–5 toxicity. 
\nConclusions
CIRT is one of the most effective nonsurgical treatments for colorectal lung metastases, which are relatively resistant to stereotactic body radiotherapy. CIRT is considered to be the least invasive approach even in patients who have undergone repeated prior thoracic metastasectomies.},
 title = {Carbon ion radiotherapy for oligo-recurrent lung metastases from colorectal cancer: a feasibility study.},
 volume = {9},
 year = {2014}
}