title: Effect of radiation therapy after radical prostatectomy on serum prostate-specific antigen measured by an ultrasensitive assay.
abstract: OBJECTIVE
  To study prospectively the impact of adjuvant radiation therapy on the serum level of prostate-specific antigen (PSA), as measured by an ultrasensitive Yang Proscheck assay in patients with detectable serum PSA and a negative metastatic survey after radical prostatectomy for T1 or T2 prostate cancer.
  
  
  METHODS
  Seventeen patients had a detectable serum PSA (2.40 +/- 2.1 ng/mL; range, 0.5 to 10) by the Yang polyclonal assay 2 to 71 months after radical prostatectomy for P2N0 (2 patients) or P3N0 (15 patients) prostate cancer. Metastatic workup (bone and computed tomography scan) was negative; 9 of 17 patients had a local recurrence documented by a positive biopsy of the vesicourethral anastomosis. All patients were treated by external radiotherapy, receiving 65 Gy on the prostate fossa over 5 weeks for an assumed low volume residual disease. Patients were followed up by determination of serum PSA every 3 months, using the Yang ultrasensitive assay for a mean duration of 14.4 months.
  
  
  RESULTS
  In 17.6% of the patients (3 of 17) PSA became undetectable (less than 0.05 ng/mL) after radiotherapy. Radiotherapy had no impact on PSA in 35.3% (6 of 17). PSA decreased after radiation therapy within 6 months in 47.1% (8 of 17) and for up to 12 months in 2 patients, with a nadir of 0.28 ng/mL. All patients in this group experienced a secondary rise in PSA a mean of 10.6 months (range, 6 to 18 months) after radiotherapy.
  
  
  CONCLUSIONS
  External radiotherapy has a limited impact on residual disease after radical prostatectomy, as assessed by its impact on PSA.
authors.affiliation: Department of Urology, Bichat Hospital, Paris, France.
authors.forename: F
authors.initials: F
authors.lastname: Haab
authors.forename: A
authors.initials: A
authors.lastname: Meulemans
authors.forename: L
authors.initials: L
authors.lastname: Boccon-Gibod
authors.forename: M C
authors.initials: MC
authors.lastname: Dauge
authors.forename: V
authors.initials: V
authors.lastname: Delmas
authors.forename: C
authors.initials: C
authors.lastname: Hennequin
authors.forename: D
authors.initials: D
authors.lastname: Benbunan
authors.forename: L
authors.initials: L
authors.lastname: Boccon-Gibod
mesh_terms: D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood*; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000532:radiotherapy* / Q000601:surgery; D018714:Radiotherapy, Adjuvant; D012680:Sensitivity and Specificity
chemical_list: D017430:Prostate-Specific Antigen