Prostate cancer presenting with normal serum PSA levels and boney metastases treated with zoledronic acid.

Prostate specific antigen (PSA) is currently the most widely used tumor marker for diagnosing and monitoring prostate cancer. Serum PSA level greater than 10 ng/mL is considered a negative predictor for the presence of bone metastases and routine use of bone scans is therefore avoided. This report describes two cases of patients presenting with normal PSA levels (0-4 ng/ mL) and positive bone scans. The value of routine use of bone scintigraphy in the follow up of these cases is therefore questioned here. Moreover the addition of bisphosphonates to the androgen deprivation treatment, achieved not only pain relief and improvement in aspects of quality of life, but also provided radiographic evidence of management of metastatic bone disease.