[Diagnostic methodology for the biochemical recurrence of prostate cancer after radiotherapy].
Due to the permanence of the prostate, PSA does not descend to undetectable levels after radical radiotherapy the way it happens after radical prostatectomy. PSA as response parameter after radiotherapy or for the characterization of biochemical recurrence is very sensitive but not much specific. The positive predictive value for local or systemic clinical recurrence is low, so that the use of PSA alone for the indication of rescue therapies is open to debate. There are different definitions of biochemical recurrence after radiotherapy. To date, the most standardized definition was that of the American Society for Therapeutic Radiology and Oncology (ASTRO) in 1996, but it was exclusive for patients treated with external beam radiotherapy as monotherapy. It was very sensitive to the follow-up time, but it was based on retrospective data, and its correlation with clinical progression was suboptimal. With the aim of improving the definition of biochemical failure ASTRO reunited a new expert commission in 2005 that gave a new definition of biochemical failure more specific for clinical events and valid in the context of short-term androgen deprivation or brachytherapy. The final recommendations were to consider biochemical recurrence a PSA increase of 2 ng/ml or greater over the nadir, or patients that have received rescue therapies. Prostate biopsy after radiotherapy is employed in patients with suspicion of exclusively local recurrence to direct them to rescue therapies. The criteria for the diagnosis of post-therapy carcinoma must be homogenized before establishing this test as a routine in the evaluation of treatment response. Standard imaging techniques for the localization of clinical recurrences (99-technetium bone scan, CT scan and MRI) are not much sensitive and it is predictable that other diagnostic tests which have a metabolic character (such as PET with various tracers, MR spectroscopy) will be used for the study of biochemical recurrence after radiotherapy in the near future.
Pijoan
Javier Maldonado
JM
Oncología Radioterápica, Hospital Vall d'Hebron, Universidad Autíonoma de Barcelona, Barcelona, España. xmaldona@vhebron.net
D006801:Humans; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000097:blood* / Q000175:diagnosis*; D016609:Neoplasms, Second Primary / Q000097:blood* / Q000175:diagnosis*; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000532:radiotherapy*
D017430:Prostate-Specific Antigen