Behind skin cancer , prostate cancer is the most common cancer in men. In fact, one man in six will be diagnosed with it during his lifetime. The American Cancer Society estimates that in 2004, more than 230,000 men will be diagnosed with prostate cancer and almost 30,000 will die from it in the United States.

Since screening for prostate cancer has become available, the death rate from prostate cancer has declined. The most common type of prostate cancer screening involves testing for prostate-specific antigen (PSA) in the blood. PSA, a protein made in the prostate, helps keep semen liquid. In a healthy male, only a small amount of PSA escapes into circulation and is measurable in the blood. Prostate cancer, as well as other prostate conditions, can cause the level of PSA in the blood to rise.

Although there is disagreement about the appropriate cutoff for a normal PSA level, a man’s chance of having prostate cancer is increased by 25% if his PSA level is greater than 4 nanograms per milliliter (ng/ml)—a level greater than 10 ng/mL increases his chance by 67%. However, this also means that many men with a PSA level higher than 4 ng/mL do not have prostate cancer, and that not all men with prostate cancer have elevated PSA levels.

An article published in the July 8, 2004 issue of the New England Journal of Medicine looked at another aspect of PSA levels—how fast PSA rises (PSA velocity). Several previously published studies have found a relationship between PSA velocity and the severity and recurrence risk of prostate cancer. The NEJM study investigated whether a relationship existed between PSA velocity and risk of death from prostate cancer.

About the Study

The study followed 1,095 men who were diagnosed with localized (no spread) prostate cancer and treated with radical prostatectomy (removal of the entire prostate). All PSA measurements that were taken within one year before diagnosis were used to calculate the PSA velocity during that time.

After the surgery, the men were followed, on average, five years and had a serum PSA measurement every six months. During follow-up, 366 disease recurrences occurred, as did 84 deaths, 27 of which were attributable to prostate cancer.

The Findings

The researchers found a significant difference between the men with an annual PSA velocity of less than 2.0 ng/mL and the men with an annual PSA velocity greater than 2.0 ng/mL. Specifically, when compared to a lower PSA velocity, an annual PSA velocity of greater than 2.0 ng/mg was associated with:

  • Shorter times to disease recurrence
  • Death from prostate cancer
  • Death from any cause

In fact, the risk of death from prostate cancer for men with an annual PSA velocity of greater than 2.0 ng/mL was almost 10 times greater than that of men below 2.0 ng/mL, despite radical proctectomy.

The authors do point out that although the study controlled for the severity of the initial cancer, and the PSA level at diagnosis, these are still important determinants of the risk of death from prostate cancer.

How Does This Affect You?

Virtually all authorities recommended annual PSA testing beginning at age 50; some advocate starting at 40. While a level greater than 4 ng/mL is cause for concern, this study confirms that a red flag should be raised not only for a higher PSA level, but also for a rapidly rising one. Yearly, or more frequent, monitoring is crucial to determine the PSA velocity.

Watchful waiting, or expectant therapy, is an option for managing prostate cancer. During it, the PSA level is carefully monitored. This treatment option is not for everyone; it is recommended when the cancer is not causing symptoms, is slow growing, is small, and the potential adverse effects of treatment would outweigh the benefits it could provide. In light of the results of this and other studies, a patient’s rapid rise in PSA levels should trigger the end of watchful waiting.