title: Potential risk of alpha-glucosidase inhibitor administration in prostate cancer external radiotherapy by exceptional rectal gas production: a case report.
abstract: BACKGROUND
  Radiotherapy is a standard treatment for prostate cancer, and image-guided radiotherapy is increasingly being used to aid precision of dose delivery to targeted tissues. However, precision during radiotherapy cannot be maintained when unexpected intrafraction organ motion occurs.
  
  
  METHODS
  We report our experience of internal organ motion caused by persistent gas production in a patient taking an alpha-glucosidase inhibitor. A 68-year-old Japanese man with prostate cancer visited our institution for treatment with helical tomotherapy. He suffered from diabetes mellitus and took an alpha-glucosidase inhibitor. Routine treatment planning computed tomography showed a large volume of rectal gas; an enema was given to void the rectum. Subsequent treatment planning computed tomography again showed a large volume of gas. After exercise (walking) to remove the intestinal gas, a third scan was performed as a test scan without tight fixation, which showed a sufficiently empty rectum for planning. However, after only a few minutes, treatment planning computed tomography again showed extreme accumulation of gas. Therefore, we postponed treatment planning computed tomography and consulted his doctor to suspend the alpha-glucosidase inhibitor, which was the expected cause of his persistent gas. Four days after the alpha-glucosidase inhibitor regimen was suspended, we took a fourth treatment planning computed tomography and made a treatment plan without gas accumulation. Thereafter, the absence of rectal gas accumulation was confirmed using daily megavolt computed tomography before treatment, and the patient received 37 fractions of intensity-modified radiotherapy at 74 Gy without rectal gas complications. In this case study, the alpha-glucosidase inhibitor induced the accumulation of intestinal gas, which may have caused unexpected organ motion, untoward reactions, and insufficient doses to clinical targets.
  
  
  CONCLUSIONS
  We suggest that patients who are taking an alpha-glucosidase inhibitor for diabetes should discontinue use of that particular medicine prior to beginning radiotherapy.
authors.forename: Takuya
authors.initials: T
authors.lastname: Nishimura
authors.affiliation: Department of Radiology, Ujitakeda Hospital, 24-1, Umonji, Uji-city, Kyoto 611-0021, Japan. hideya10@hotmail.com.
authors.forename: Hideya
authors.initials: H
authors.lastname: Yamazaki
authors.forename: Kazuki
authors.initials: K
authors.lastname: Iwama
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Oota
authors.forename: Norihiro
authors.initials: N
authors.lastname: Aibe
authors.forename: Satoaki
authors.initials: S
authors.lastname: Nakamura
authors.forename: Ken
authors.initials: K
authors.lastname: Yoshida
authors.forename: Haruumi
authors.initials: H
authors.lastname: Okabe
authors.forename: Kei
authors.initials: K
authors.lastname: Yamada
mesh_terms: D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000188:drug therapy*; D005414:Flatulence / Q000139:chemically induced* / Q000000981:diagnostic imaging; D065089:Glycoside Hydrolase Inhibitors / Q000009:adverse effects*; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000150:complications / Q000532:radiotherapy*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012007:Rectum / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed
chemical_list: D065089:Glycoside Hydrolase Inhibitors