INTRODUCTION: Prostate cancer is the most common nonskin malignancy affecting men and is the second leading cause of cancer-related death in North America. The incidence of prostate cancer increases dramatically with age. However, many health authorities advocate the cessation of routine prostate cancer testing in men older than 75 because of the belief that most patients will have a clinically insignificant cancer and will not benefit from therapy. The true prevalence of clinically significant prostate cancer in elderly men is not known.
METHODS: We analyzed 1446 needle biopsies of the prostate in men aged 75 or older. All pathological reviews were conducted by the pathology department at the Methodist Hospital in Houston, Tex. Data were collected from pathology reports, hospital and clinic databases, and medical records when available. Data obtained included age at biopsy, serum prostate-specific antigen (PSA) levels, number of positive core biopsies and Gleason grade. Statistical analysis was performed using Stata. Clinically significant cancer was defined by the pathological presence of Gleason grade 6 adenocarcinoma in more than 1 biopsy core or the presence of any Gleason 4 or 5 component in the biopsy.
RESULTS: The median age of the patients included in the study was 78.8 and 95% of the patients were between the ages of 75 and 85. The mean serum PSA level for patients biopsied was 10.4 mug/L. Of all biopsies reviewed, 53% were positive for prostate cancer and 78% of these would be defined as clinically significant cancer. Regression analysis revealed age to be a significant (p < 0.05) factor for increased Gleason grade in positive biopsies. Logistic regression revealed age as a significant factor (p < 0.05) for clinically significant prostate cancer even when controlling for PSA. A serum PSA threshold value of 6.5 mug/L would have missed 38% of significant cancers and a threshold of 4.0 mug/L would have missed 8% of significant cancers.
CONCLUSION: Our findings suggest that the prevalence of clinically significant prostate cancer in the elderly population may be higher than previously thought. As the population continues to live longer and healthier lives, it will become more common to confront prostate cancer morbidity in the eldery population. Using higher serum PSA thresholds to eliminate unnecessary biopsies in older men does not appear to help identify patients at greater risk of having clinically significant prostate cancer. Patients with prostate cancer having aggressive clinical features may benefit from treatment of their prostate cancer well into their eighth and ninth decades of life. Testing and diagnostic recommendations should reflect the potential benefit of identifying patients with aggressive prostate cancer even after age 75.