Prognostic factors in metastatic prostate cancer

Androgen deprivation therapy is the initial treatment choice for metastatic disease. When enrolling patients into androgen deprivation trials, it is important to consider stratification of enrollees based on prognostic factors that have been identified as important in determining the likelihood of response. Prognostic factors are also helpful in identifying which patients are less likely to respond to treatment; this information also would help to counsel patients. Performance status is an important prognostic factor; however, its impact is minimal because the great majority of men who receive treatment for advanced disease have a normal performance status. Hemoglobin, alkaline phosphatase, and a semiquantitative grading scale for the number of metastatic foci on the bone scan are useful prognostic factors. The pretreatment serum testosterone level is a powerful prognostic factor. Patients with a low serum testosterone level have a shorter progression-free survival than men whose pretreatment serum testosterone level is above normal. The prognostic importance of pretreatment serum testosterone level has been evaluated in studies using treatment methods that lower this level to castrate levels. Recently, we found that serum testosterone level was not a prognostic factor for men taking the nonsteroidal antiandrogen, Casodex (Zeneca, Wilmington, DE), which does not alter the serum testosterone level. The pretreatment serum prostatic-specific antigen also is a prognostic factor. This antigen may be the best single method for monitoring patients in regard to response to or progression following therapy. The return of the prostatic-specific antigen level to normal (< 4 ng/ml), or the decline in the prostatic-specific antigen level of > 90% indicates a prolonged progression-free survival. In the future, it will be interesting to incorporate both the initial prognostic factors as well as monitor the prostatic-specific antigen into a multivariate analysis, which will be highly predictive of a man's response to treatment.