Among men undergoing androgen deprivation therapy for metastatic prostate cancer, those who achieve a low PSA level by seven months after the start of treatment experience significantly better survival. These results were published in the Journal of Clinical Oncology.
Prostate-specific antigens (PSA) are proteins that are normally shed by the prostate and can be found in circulating blood. PSA levels that are elevated may indicate the presence or progression of prostate cancer. PSA levels are often monitored during and following treatment for prostate cancer to measure a patient’s response to treatment.
Androgen deprivation therapy, also known as hormonal therapy, is designed to block testosterone from stimulating the growth of hormone-dependent types of prostate cancer. Among men with metastatic prostate cancer (cancer that has spread beyond the prostate to distant sites in the body), androgen deprivation therapy is often used to relieve symptoms. Androgen deprivation can be achieved through the use of medications or by surgically removing the testicles.
Survival varies among men treated with androgen deprivation therapy, prompting interest in identifying patient or tumor characteristics that can be used to predict prognosis.
To explore the relationship between post-treatment PSA level and survival, researchers conducted a study among 1,395 men with metastatic prostate cancer. The men had baseline PSA levels of 5 ng/mL or higher. The initial course of androgen deprivation therapy consisted of seven months of Zoladex® (goserelin) and Casodex® (bicalutamide).
- At the end of seven months of androgen deprivation therapy, 965 men (69%) had PSA values that were 4.0 ng/mL or less. Very low PSA levels (0.2 ng/mL or less) were achieved by 604 of these men.
- Compared to men with a PSA greater than 4.0 ng/mL, men with a PSA between 0.2 ng/mL and 4.0 ng/mL had a 70% reduction in risk of death, and men with a PSA of 0.2 ng/mL or less had an 83% reduction in risk of death.
- The survival achieved by more than half the men was 13 months among those with a PSA greater than 4.0 ng/mL, 44 months among those with a PSA between 0.2 ng/mL and 4.0 ng/mL, and 75 months among those with a PSA of 0.2 ng/mL or less.
The researchers conclude that men who achieve a PSA level of 4.0 ng/mL or less after seven months of androgen deprivation therapy for metastatic prostate cancer experience significantly better survival than men with higher PSA levels.
Reference: Hussain M, Tangen CM, Higano C et al. Absolute Prostate-specific antigen Value after Androgen Deprivation is a Strong Independent Predictor of Survival in New Metastatic Prostate Cancer: Data from Southwest Oncology Group Trial 9346 (INT-0162). Journal of Clinical Oncology. 2006;24:3984-3990.
Related News:Urologists Play Large Role in Determining Which Patients Receive Androgen Deprivation Therapy (6/23/2006)
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