title: Focal dose escalation using FDG-PET-guided intensity-modulated radiation therapy boost for postoperative local recurrent rectal cancer: a planning study with comparison of DVH and NTCP.
abstract: BACKGROUND
  To evaluate the safety of focal dose escalation to regions with standardized uptake value (SUV) >2.0 using intensity-modulated radiation therapy (IMRT) by comparison of radiotherapy plans using dose-volume histograms (DVHs) and normal tissue complication probability (NTCP) for postoperative local recurrent rectal cancer
  
  
  METHODS
  First, we performed conventional radiotherapy with 40 Gy/20 fr. (CRT 40 Gy) for 12 patients with postoperative local recurrent rectal cancer, and then we performed FDG-PET/CT radiotherapy planning for those patients. We defined the regions with SUV > 2.0 as biological target volume (BTV) and made three boost plans for each patient: 1) CRT boost plan, 2) IMRT without dose-painting boost plan, and 3) IMRT with dose-painting boost plan. The total boost dose was 20 Gy. In IMRT with dose-painting boost plan, we increased the dose for BTV+5 mm by 30% of the prescribed dose. We added CRT boost plan to CRT 40 Gy (summed plan 1), IMRT without dose-painting boost plan to CRT 40 Gy (summed plan 2) and IMRT with dose-painting boost plan to CRT 40 Gy (summed plan 3), and we compared those plans using DVHs and NTCP.
  
  
  RESULTS
  D(mean) of PTV-PET and that of PTV-CT were 26.5 Gy and 21.3 Gy, respectively. V50 of small bowel PRV in summed plan 1 was significantly higher than those in other plans ((summed plan 1 vs. summed plan 2 vs. summed plan 3: 47.11 +/- 45.33 cm3 vs. 40.63 +/- 39.13 cm3 vs. 41.25 +/- 39.96 cm3 (p < 0.01, respectively)). There were no significant differences in V30, V40, V60, D(mean) or NTCP of small bowel PRV.
  
  
  CONCLUSIONS
  FDG-PET-guided IMRT can facilitate focal dose-escalation to regions with SUV above 2.0 for postoperative local recurrent rectal cancer.
authors.affiliation: Department of Radiation Oncology, Tohoku University School of Medicine, Sendai, Japan. kjingu-jr@rad.med.tohoku.ac.jp
authors.forename: Keiichi
authors.initials: K
authors.lastname: Jingu
authors.forename: Hisanori
authors.initials: H
authors.lastname: Ariga
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kaneta
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Takai
authors.forename: Ken
authors.initials: K
authors.lastname: Takeda
authors.forename: Lindel
authors.initials: L
authors.lastname: Katja
authors.forename: Kakutaro
authors.initials: K
authors.lastname: Narazaki
authors.forename: Takahiro
authors.initials: T
authors.lastname: Metoki
authors.forename: Keisuke
authors.initials: K
authors.lastname: Fujimoto
authors.forename: Rei
authors.initials: R
authors.lastname: Umezawa
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Ogawa
authors.forename: Kenji
authors.initials: K
authors.lastname: Nemoto
authors.forename: Masashi
authors.initials: M
authors.lastname: Koto
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Mitsuya
authors.forename: Naruhiro
authors.initials: N
authors.lastname: Matsufuji
authors.forename: Shoki
authors.initials: S
authors.lastname: Takahashi
authors.forename: Shogo
authors.initials: S
authors.lastname: Yamada
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage; D004307:Dose-Response Relationship, Radiation; D004338:Drug Combinations; D019788:Fluorodeoxyglucose F18; D006801:Humans; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000532:radiotherapy*; D010094:Oxonic Acid / Q000008:administration & dosage; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000532:radiotherapy* / Q000601:surgery; D005641:Tegafur / Q000008:administration & dosage
chemical_list: D000964:Antimetabolites, Antineoplastic; D004338:Drug Combinations; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; C079198:S 1 (combination); D005641:Tegafur; D010094:Oxonic Acid