title: Three-dimensional conformal arc radiotherapy using a C-arm linear accelerator with a computed tomography on-rail system for prostate cancer: clinical outcomes.
abstract: BACKGROUND
  We report the feasibility and treatment outcomes of image-guided three-dimensional conformal arc radiotherapy (3D-CART) using a C-arm linear accelerator with a computed tomography (CT) on-rail system for localized prostate cancer.
  
  
  METHODS
  Between 2006 and 2011, 282 consecutive patients with localized prostate cancer were treated with in-room CT-guided 3D-CART. Biochemical failure was defined as a rise of at least 2.0 ng/ml beyond the nadir prostate-specific antigen level. Toxicity was scored according to the National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0.
  
  
  RESULTS
  A total of 261 patients were analyzed retrospectively (median follow-up: 61.6 months). The median prescribed 3D-CART dose was 82 Gy (2 Gy/fraction, dose range: 78-86 Gy), and 193 of the patients additionally received hormonal therapy. The 5-year overall survival rate was 93.9 %. Among low-, intermediate-, and high-risk patients, 5-year rates of freedom from biochemical failure were 100, 91.5 and 90.3 %, respectively. Rates of grade 2-3 late gastrointestinal and genitourinary toxicities were 2.3 and 11.4 %, respectively. No patient experienced late grade 4 or higher toxicity.
  
  
  CONCLUSIONS
  In-room CT-guided 3D-CART was feasible and effective for localized prostate cancer. Treatment outcomes were comparable to those previously reported for intensity-modulated radiotherapy.
authors.affiliation: Department of Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan. akumabe@rad.med.keio.ac.jp.|Division of Radiation Oncology, Department of Radiology, Sagamihara Kyodo Hospital, 2-8-18 Hashimoto, Midori-ku, Sagamihara, Kanagawa, 252-0143, Japan. akumabe@rad.med.keio.ac.jp.
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Kumabe
authors.affiliation: Division of Radiation Oncology, Department of Radiology, Sagamihara Kyodo Hospital, 2-8-18 Hashimoto, Midori-ku, Sagamihara, Kanagawa, 252-0143, Japan. noborufukuhara@gmail.com.
authors.forename: Noboru
authors.initials: N
authors.lastname: Fukuhara
authors.affiliation: Department of Urology, Sagamihara Kyodo Hospital, 2-8-18 Hashimoto, Midori-ku, Sagamihara, Kanagawa, 252-0143, Japan. t-utsunomiya@sagamiharahp.com.
authors.forename: Takuji
authors.initials: T
authors.lastname: Utsunomiya
authors.affiliation: Department of Radiation Oncology, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo, 162-8655, Japan. tkawase@hosp.ncgm.go.jp.
authors.forename: Takatsugu
authors.initials: T
authors.lastname: Kawase
authors.affiliation: Division of Radiation Oncology, Department of Radiology, Sagamihara Kyodo Hospital, 2-8-18 Hashimoto, Midori-ku, Sagamihara, Kanagawa, 252-0143, Japan. iwata92@gmail.com.
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Iwata
authors.affiliation: Division of Radiation Oncology, Department of Radiology, Sagamihara Kyodo Hospital, 2-8-18 Hashimoto, Midori-ku, Sagamihara, Kanagawa, 252-0143, Japan. y.okada@marianna-u.ac.jp.|Department of Radiology, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki, Kanagawa, 216-8511, Japan. y.okada@marianna-u.ac.jp.
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Okada
authors.affiliation: Department of Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan. sutani-shinya@rad.med.keio.ac.jp.
authors.forename: Shinya
authors.initials: S
authors.lastname: Sutani
authors.affiliation: Department of Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan. ohashi@rad.med.keio.ac.jp.
authors.forename: Toshio
authors.initials: T
authors.lastname: Ohashi
authors.affiliation: Department of Urology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan. moto-oya@z3.keio.jp.
authors.forename: Mototsugu
authors.initials: M
authors.lastname: Oya
authors.affiliation: Department of Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan. shige@rad.med.keio.ac.jp.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Shigematsu
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000532:radiotherapy*; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D010315:Particle Accelerators; D011471:Prostatic Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D011881:Radiotherapy, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000295:instrumentation / Q000379:methods*; D061089:Radiotherapy, Image-Guided / Q000295:instrumentation / Q000379:methods*; D012189:Retrospective Studies