title: Granulomatous Prostatitis After Intravesical Bacillus Calmette-Guérin Instillation Therapy: A Potential Cause of Incidental F-18 FDG Uptake in the Prostate Gland on F-18 FDG PET/CT in Patients with Bladder Cancer.
abstract: OBJECTIVE
  This study aimed to evaluate the possibility that Bacillus Calmette-Guérin (BCG)-induced granulomatous prostatitis can be a potential cause of benign F-18 FDG uptake.
  
  
  METHODS
  A total of 395 bladder cancer patients who underwent F-18 FDG PET/CT (PET/CT) were retrospectively evaluated. Patients were divided into two groups according to BCG therapy status. Elapsed time after BCG therapy, serum PSA level, results of prostate biopsy, and the SUVmax and uptake pattern in the prostate gland were reviewed. For patients who underwent follow-up PET/CT, the changes in SUVmax were calculated.
  
  
  RESULTS
  While 35 % of patients showed prostate uptake in the BCG therapy group, only 1 % showed prostate uptake in the non-BCG therapy group (p < 0.001). Among 49 patients with FDG-avid prostate lesions, none had suspected malignancy during the follow-up period (median: 16 months). Five patients revealed granulomatous prostatitis on biopsy. The incidence of FDG-avid prostate lesions was significantly higher if the elapsed time after BCG therapy was less than 1 year compared to more than 1 year (p < 0.001). Serum PSA was normal in 88 % of patients. All patients with incidental F-18 FDG uptake in the prostate gland showed focal or multifocal prostate uptake, and median SUVmax was 4.7. In 16 patients who underwent follow-up PET/CT, SUVmax was decreased in 14 patients (88 %) without treatment, and no patients demonstrated further increased prostate uptake (p < 0.001).
  
  
  CONCLUSIONS
  BCG-induced granulomatous prostatitis can be a potential cause of benign F-18 FDG uptake, especially in those with a history of bladder cancer treated with BCG. In BCG-induced granulomatous prostatitis, focal or multifocal prostate uptake is frequently seen within 1 year after BCG therapy, and the intensity of prostate uptake is decreased on the follow-up PET/CT without any treatment.
authors.affiliation: Department of Nuclear Medicine, Kyungpook National University Medical Center and School of Medicine, 807 Hoguk-ro, Buk-gu, Daegu, 702-210 Republic of Korea.
authors.forename: Choon-Young
authors.initials: CY
authors.lastname: Kim
authors.affiliation: Department of Nuclear Medicine, Kyungpook National University Medical Center and School of Medicine, 807 Hoguk-ro, Buk-gu, Daegu, 702-210 Republic of Korea.
authors.forename: Sang-Woo
authors.initials: SW
authors.lastname: Lee
authors.affiliation: Department of Urology, Kyungpook National University Medical Center and School of Medicine, 807 Hoguk-ro, Buk-gu, Daegu, 702-210 Republic of Korea.
authors.forename: Seock Hwan
authors.initials: SH
authors.lastname: Choi
authors.affiliation: Department of Nuclear Medicine, Kyungpook National University Medical Center and School of Medicine, 807 Hoguk-ro, Buk-gu, Daegu, 702-210 Republic of Korea.
authors.forename: Seung Hyun
authors.initials: SH
authors.lastname: Son
authors.affiliation: Department of Nuclear Medicine, Kyungpook National University Medical Center and School of Medicine, 807 Hoguk-ro, Buk-gu, Daegu, 702-210 Republic of Korea.
authors.forename: Ji-Hoon
authors.initials: JH
authors.lastname: Jung
authors.affiliation: Department of Nuclear Medicine, Kyungpook National University Medical Center and School of Medicine, 807 Hoguk-ro, Buk-gu, Daegu, 702-210 Republic of Korea.
authors.forename: Chang-Hee
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Department of Nuclear Medicine, Kyungpook National University Medical Center and School of Medicine, 807 Hoguk-ro, Buk-gu, Daegu, 702-210 Republic of Korea.
authors.forename: Shin Young
authors.initials: SY
authors.lastname: Jeong
authors.affiliation: Department of Nuclear Medicine, Kyungpook National University Medical Center and School of Medicine, 807 Hoguk-ro, Buk-gu, Daegu, 702-210 Republic of Korea.
authors.forename: Byeong-Cheol
authors.initials: BC
authors.lastname: Ahn
authors.affiliation: Department of Nuclear Medicine, Kyungpook National University Medical Center and School of Medicine, 807 Hoguk-ro, Buk-gu, Daegu, 702-210 Republic of Korea.
authors.forename: Jaetae
authors.initials: J
authors.lastname: Lee
keywords: Bladder cancer; F-18 FDG PET/CT; Granulomatous prostatitis; Intravesical BCG therapy