Surveillance of patients with prostate cancer after treatment: The roles of serologic and imaging studies

Abstract

The asymptomatic patient who has been treated with a curative intent by surgery or irradiation for cancer of the prostate needs only a PSA and a baseline bone scan for his initial (post-treatment) follow-up. Rising serum PSA levels which still remain in the moderate range may signal a local recurrence, but this must be documented histologically. The therapeutic options to consider for a documented local recurrence include pelvic irradiation for the previously operated patient, or surgery for a post-irradiation recurrence. A serum PSA which rises to high levels following treatment will often be associated with distant metastases, and this is more certain if the original tumor was locally advanced and/or the histology was poorly differentiated or aneuploid. A newly elevated serum acid phosphatase in a treated patient with prostate cancer will usually signify disseminated disease also. Whether to wait until a patient becomes symptomatic from a recurrence or to initiate endocrine treatment solely on the basis of a rising serum marker still remains a point of controversy. The overall survival of Stage D2 patients has not been prolonged by endocrine manipulations which were instituted before symptoms of widespread dissemination appeared. The routine use of periodic imaging studies to follow asymptomatic patients with prostate cancer after they have received treatment cannot be justified for clinical decision-making purposes. On the other hand, in treated patients who develop new symptoms suggesting bone metastases, radionuclide scans which are correlated carefully with the patient's symptoms and with radiographs of "hot" areas on the scans are indicated. When a suspected diagnosis of metastatic disease still remains in doubt, elevated serum tumor markers may provide additional evidence. Imaging studies can also be used to guide percutaneous biopsies of suspected metastases in bones (radionuclide scans and radiographs), or of persistent tumor in an irradiated prostate gland or at the urethro-vesical junction after surgery (TRUS). Since cancer of the prostate often progresses slowly and disseminated disease remains incurable at this time, some degree of uncertainty about the presence of metastases or of recurrent local disease might be safer and less costly than the use of multiple diagnostic studies and aggressive treatment (including endocrine manipulations) in nonsymptomatic patients.