Positron emission tomography in uro-oncology.

Positron emission tomography (PET) in uro-oncology has been one of the slowest areas to develop. There are problems because of the excretion of tracer through the renal tract. Its use in prostate cancer has generally being disappointing, with PET being unable to differentiate malignancy from benign prostatic hypertrophy. In more advanced disease and in the search for the site of recurrence, PET can be of more use. Also, new tracers may prove to be more effective. PET has been shown to be of value in testicular cancer, particularly in defining recurrent disease in residual masses and in patients with raised markers. There is a clear place for PET in some of these cases. Early studies at staging are promising but more work is required to define its exact place. In renal and bladder cancer, PET may be a useful adjunct to conventional imaging in difficult cases and may assist in local staging. In all tumours it is valuable to differentiate fibrosis from recurrent disease in the treatment bed, an area of difficulty for CT/MR.