Prognostic significance of changes in prostate-specific markers after endocrine treatment of stage D2 prostatic cancer.
BACKGROUND: The prognostic value was determined of prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) measured before and after endocrine treatment in 57 patients with newly diagnosed Stage D2 prostatic cancer. METHODS: Therapy included orchiectomy or administration of luteinizing hormone releasing hormone analogues or an antiandrogen. RESULTS: The absolute pretreatment PSA (elevated in 100% of patients) but not PAP (abnormal in 93%) predicted disease progression (P < 0.0011), i.e., a poor response to therapy. Fifty-three patients responded to androgen deprivation with a decrease in PSA level. This declined to normal at 3 and 6 months in 25% of patients. Forty-nine percent had a greater than 90% decrease in their PSA level. By 1 year, 58% of patients had progressive disease. Both the nadir PSA level and the percent decline from the pretreatment level at 3 and 6 months predicted the progression-free interval (P < 0.001). Patients with a 90% or greater decline in PSA had a prolonged progression-free survival. Serial PAP levels were similarly prognostic. CONCLUSION: It was concluded that PSA was better than PAP in evaluating patients before and after androgen-deprivation therapy. The nadir level of both markers was an important tool to predict progression-free survival in patients with metastatic prostatic cancer.