title: Relationship between prostate-specific antigen bounce body fat distribution and body mass index in permanent seed brachytherapy for prostate cancer.
abstract: OBJECTIVE
  To analyze the influence of body mass index (BMI) and adipose tissue distribution on prostate-specific antigen (PSA) bounce after iodine-125 prostate brachytherapy.
  
  
  METHODS
  We studied 20 patients who had PSA bounce (≥0.50ng/mL) after exclusive prostate brachytherapy. These patients were compared with 48 patients without a bounce (<0.50ng/mL). All patients in the comparison group had a followup of ≥24 months and a last PSA ≤0.5ng/mL. Within these 48 patients, there was a group matched for age (n=20). Univariate and multivariate logistic models were estimated to assess the association between age, baseline PSA, prostate volume, D(90), visceral fat (VF) volume, and BMI on PSA-bouncing status.
  
  
  RESULTS
  When comparing the patients with a bounce to those without, only BMI showed a significantly different distribution (mean, 25.18 vs. 27.47kg/m(2); p=0.0342). On a multivariate analysis, BMI had an odds ratio of 0.85 (95% confidence interval, 0.71-0.99, p=0.049), indicating that an increase of 1kg/m(2) in BMI is associated with a 15% reduction in the odds of having a bounce. In the univariate analysis with the matching patients, BMI was a significant predictor of a bounce (p=0.0147). In the multivariate conditional logistic model, BMI showed a trend toward an influence on a bounce (p=0.0615). All other factors, including VF, did not have any influence on a PSA bounce.
  
  
  CONCLUSIONS
  Patients with a lower BMI are more likely to experience a PSA bounce ≥0.50ng/mL. VF did not have an influence on a PSA bounce.
authors.affiliation: Department of Radiation Oncology, Centre Hospitalier de l'Université de Montréal (CHUM), Hôpital Notre-Dame, Montreal, Canada.
authors.forename: Guila
authors.initials: G
authors.lastname: Delouya
authors.forename: Daniel
authors.initials: D
authors.lastname: Taussky
authors.forename: Catherine Ran
authors.initials: CR
authors.lastname: Ji
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Sylvestre
authors.forename: David
authors.initials: D
authors.lastname: Donath
mesh_terms: D000367:Age Factors; D000368:Aged; D050218:Body Fat Distribution; D015992:Body Mass Index; D001918:Brachytherapy / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009929:Organ Size / Q000528:radiation effects; D011467:Prostate / Q000473:pathology; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000532:radiotherapy*
chemical_list: D017430:Prostate-Specific Antigen