title: Prostate-specific Antigen Mass Density--A Measure Predicting Prostate Cancer Volume and Accounting for Overweight and Obesity-related Prostate-specific Antigen Hemodilution.
abstract: OBJECTIVE
  To test prostate-specific antigen mass density (PSAMD) as a predictor of total tumor volume (TTV) at radical prostatectomy (RP).
  
  
  METHODS
  We conducted a detailed pathologic analysis of 469 RP from men with NCCN low-risk prostate cancer who had Gleason score of 3 + 3 = 6 (grade group 1) at RP. We then compared the ability of PSA, PSA density (PSAD), PSA mass (PSAM-absolute amount of PSA in patient's circulation), and PSAM density (PSAM divided by prostate weight without seminal vesicles) to predict TTV at RP. PSAM was calculated by multiplying plasma volume (estimated body surface [weight, kg(0.425) × height, m(0.72) × 0.007184] × 1.67) by PSA. Performance of the above measures in different BMI categories was assessed. Kruskal-Wallis test was used to compare the means and Spearman's rank correlation coefficient to assess the correlations.
  
  
  RESULTS
  The 469 men were normal weight (n = 129), overweight (n = 253), and obese (n = 87). Mean age of the patients' was 57.4 years and PSA of 4.53 ng/ml. Increase of prostate weight with body mass index (BMI) was reflected in PSAM (both P <.001) but not in other measures. BMI did not correlate with TTV and PSA. Among PSA, PSAD, PSAM, and PSAMD, PSAMD had the highest correlation with TTV (r = 0.336; P <.001). Prostate weight had stronger (negative) association with PSAMD (r = -0.394; <.001) than TTV.
  
  
  CONCLUSIONS
  PSAMD is the biochemical measure with the best correlation with TTV at RP. Unlike other measures, it is not affected by BMI-related hemodilution. Thresholds should be established to use this more objective measure clinically in surveillance algorithms and in planning radical prostatectomy.
authors.affiliation: Department of Pathology & Laboratory Medicine and Urology, and Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL. Electronic address: o.kryvenko@med.miami.edu.
authors.forename: Oleksandr N
authors.initials: ON
authors.lastname: Kryvenko
authors.affiliation: Vattikuti Urology Institute, Henry Ford Hospital, Detroit, MI.
authors.forename: Mireya
authors.initials: M
authors.lastname: Diaz
authors.affiliation: Department of Pathology, Rhode Island Hospital and Brown University, Providence, RI.
authors.forename: Andres
authors.initials: A
authors.lastname: Matoso
authors.affiliation: Department of Urology, The Johns Hopkins Medical Institutions, Baltimore, MD.
authors.forename: Max
authors.initials: M
authors.lastname: Kates
authors.affiliation: The Johns Hopkins Medical School, Baltimore, MD.
authors.forename: Jason
authors.initials: J
authors.lastname: Cohen
authors.affiliation: Department of Radiation Oncology, UT Health Science Center, San Antonio, TX.
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Swanson
authors.affiliation: Department of Urology, The Johns Hopkins Medical Institutions, Baltimore, MD; Department of Pathology, The Johns Hopkins Medical Institutions, Baltimore, MD; Department of Oncology, The Johns Hopkins Medical Institutions, Baltimore, MD.
authors.forename: Jonathan I
authors.initials: JI
authors.lastname: Epstein
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000150:complications; D050177:Overweight / Q000097:blood* / Q000150:complications; D010953:Plasma Volume; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000097:blood*; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000097:blood* / Q000150:complications / Q000473:pathology / Q000601:surgery; D047368:Tumor Burden
chemical_list: D017430:Prostate-Specific Antigen