[Bone scan and prostate cancer]

Prostatic cancer has a great predilection for bone. The evaluation of its extension towards the skeleton is based on the bone scan, which has a better sensitivity than radiological examinations and clinical evaluation. Bone scan evaluation of the osseous extension, allowed a better comprehension of the mechanism of dissemination, the assumption of Batson appearing currently not very plausible. The importance of the osseous extension on the bone scan has a prognostic value; it constitutes one of the significant parameters of stratification in clinical trials. The indications of bone scan have been greatly modified since the introduction of prostate-specific antigen (PSA). At the initial assessment, the of bone scan should be indicated only if the rate of PSA exceeds 10-20 ng/mL, in the event of low grade tumor and pain. In the follow-up, the evolution of the PSA constitutes the major element of monitoring. After radical therapy, a rise in the PSA indicates bone scan, particularly if the level exceeds 10 ng/mL. In stage D2, routine bone scan is no longer indicated, except in phases II and III of the clinical trials.