Prostate Cancer Testing
The Growth Rate Factor
The second recent study (New England Journal of Medicine, v 351, p125, 2004) correlates the "Preoperative PSA Velocity" (PPV) with the risk of death from prostate cancer after radical prostatectomy. PPV is the rate of increase, per year, in the measured PSA value. Radical prostatectomy is the complete removal of the prostate.
The study included 1095 men with localized prostate cancer. Their median age was 65 (spanning 43 to 84). 95 percent had a PSA below 10 ng/milliliter, the median being 4.3, range from 0.3 to 58.2. Two more numbers are used to evaluate the cancer: the Gleason score and the T stage of the cancer. Initially, 71% of the men were at stage T1C (cancer detectable by needle biopsy only).
Median followup was for 5.1 years. The researchers found that for PPV's greater than 2, there was a 5% chance of finding cancer in lymph nodes, a higher percent had later T stages, and higher Gleason scores. After 10 years, the recurrence rate of cancer was approximately double, the death rate from any cause was more than double, and the death rate from prostate cancer was 10 times higher (3 - 34 Margin of Error).
The paper concludes by stating that "men whose PSA level increases by 2 ng/milliliter during the year before the diagnosis of prostate cancer may have a high risk of dying from prostate cancer despite undergoing radical prostatectomy. For these men... watchful waiting may not be the best option." There is no suggestion as to what treatment, if any, may provide a better outcome.
Later studies (Journal of the National Cancer Institute, received online March 2010, accepted January 2011, Vickers et. al.) provide the results obtained from the Prostate Cancer Prevention Trial involving 5519 men. They find that the PSA velocity has almost no effect on the diagnosis and prognosis of prostate cancer, when all other factors such as age, race, PSA levels, and digital rectal exam outcome are considered. The authors of this study conclude that PSA velocity should not be included in prostate cancer screening guidelines.