title: The use of prostate-specific antigen (PSA) for the monitoring of radiation therapy in prostate cancer.
abstract: BACKGROUND
  The classic methods for surveilling the efficacy of radiotherapy in prostate cancer are not accurate enough. The objective of this analysis was to determine whether prostate-specific antigen could perform this task.
  
  
  METHODS
  From 1/95 to 10/95, 16 patients were treated at our clinic. 7 of these underwent primary irradiation, 4 treatment for local recurrence, and 5 had adjuvant radiotherapy. Radiotherapy was carried out with a total dose of 60 Gy in 30 fractions, 10 fractions per week, to the prostate bed plus 2 cm safety margin.
  
  
  RESULTS
  PSA levels usually start to decline between the 3rd and the 4th week of radiotherapy with a half-life of 2.5 months. Five patients had equal or rising PSA levels, including all three patients with recurrent tumor.
  
  
  CONCLUSIONS
  In most cases, PSA declined continuously from the 3rd week of therapy. Our median half-life was similar to other reported results. Persisting or rising PSA levels are an indicator for local or distant recurrence; all our patients who developed a recurrence showed a corresponding PSA increase.
authors.affiliation: Klinik und Poliklinik für Strahlentherapie-Radioonkologie, Westfälischen Wilhelms-Universität Münster, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Schäfer
authors.forename: O
authors.initials: O
authors.lastname: Micke
authors.forename: G
authors.initials: G
authors.lastname: Hampel
authors.forename: B
authors.initials: B
authors.lastname: Brandt
authors.forename: A
authors.initials: A
authors.lastname: Bovenschulte
authors.forename: A
authors.initials: A
authors.lastname: Semjonow
authors.forename: N
authors.initials: N
authors.lastname: Willich
mesh_terms: D006801:Humans; D008297:Male; D009364:Neoplasm Recurrence, Local; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000532:radiotherapy*
chemical_list: D017430:Prostate-Specific Antigen