title: Predictive value of prostate specific antigen nadir after salvage cryotherapy.
abstract: OBJECTIVE
  We determined nadir prostate specific antigen (PSA) after salvage cryotherapy to distinguish patients who are potentially cured from those at risk for subsequent biochemical and biopsy proved failure.
  
  
  METHODS
  A total of 146 patients who underwent salvage cryotherapy were followed a median of 21 months (range 3 to 47) with regular serum PSA analysis and digital rectal examination. Sextant biopsies were performed at 6 months or earlier when PSA increased greater than 2 ng./ml. from the nadir value (biochemical failure) or there was a palpable local recurrence. We compared the incidence of biochemical failure and biopsy specimens positive for cancer to pretreatment PSA and posttreatment nadir PSA.
  
  
  RESULTS
  In 59 of the 146 patients (40%) PSA decreased to an undetectable level within a median of 3 months. In 85 of the 109 patients (78%) who underwent biopsy the specimens were negative for cancer. Low serum PSA nadir values were associated with low pretreatment PSA and a low incidence of biochemical failure. In 6 of 60 patients (10%) in whom PSA nadir was 0.5 ng./ml. or less and in 18 of 49 (37%) with a higher PSA nadir biopsy was positive for cancer.
  
  
  CONCLUSIONS
  A PSA nadir of 0.5 ng./ml. or less should be achieved after salvage cryotherapy. Higher nadirs are more likely to be associated with increasing posttreatment PSA and positive biopsies. PSA nadir is a better prognostic indicator of biochemical and biopsy proved failure after salvage cryotherapy than pretreatment PSA.
authors.affiliation: Department of Urology, University of Texas M. D. Anderson Cancer Center, Houston 77030, USA.
authors.forename: G F
authors.initials: GF
authors.lastname: Greene
authors.forename: L L
authors.initials: LL
authors.lastname: Pisters
authors.forename: S M
authors.initials: SM
authors.lastname: Scott
authors.forename: A C
authors.initials: AC
authors.lastname: Von Eschenbach
mesh_terms: D017679:Cryotherapy; D018450:Disease Progression; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000628:therapy*; D016879:Salvage Therapy
chemical_list: D017430:Prostate-Specific Antigen