Prostate Cancer Screening
A key to curing prostate cancer is to diagnose it when it is localized. This has become a very controversial topic and there are some medical groups that recommend against screening for prostate cancer. However, many patient advocate groups as well as the following organizations support prostate cancer screening, as does the Department of Urology at UMass: the American Urologic Association, the American Cancer Society, and the Massachusetts Department of Health. Key to prostate cancer screening is making sure that patients are educated and the benefits and risks of prostate cancer screening and is involved in shared decision-making with his physicians. The overview of prostate cancer screening below is designed to be educational and does not substitute for the personalized conversation between a patient and his physician.
Prostate cancer screening consists of two components: (1) a digital rectal exam, and (2) the PSA blood test.
Digital Rectal Exam
A traditional component of prostate cancer screening is the digital rectal exam [DRE], in which a physician’s finger is inserted into a patient’s rectum to feel the prostate for any areas of firmness (induration) or any masses (nodularity), two conditions that may represent cancer. As 25% of men with prostate cancer have “normal’ PSA values, the digital exam remains a crucial component of prostate cancer screening.
The PSA Blood Test
The prostate specific antigen test (or PSA test) has changed the detection of prostate cancer and is used both to screen men for prostate cancer and to monitor the effects of treatment, if chosen. Once a prostate cancer is diagnosed, PSA tests can help guide both the physician and patient in choosing the most appropriate and efficacious treatment approach. In addition, PSA can be used to follow patients after treatment.
The UMass Department of Urology faculty recommends PSA screening for just about all men when they reach 50 years of age. Because prostate cancer tends to be most prevalent among men with first-degree male relatives who have prostate cancer and among men with African American ethnicity, for those patients we believe that PSA screening should begin by age 40 or 45. Once a baseline value is established, the frequency of screening can be optimized. Ultimately, an age limit can be established as to when PSA screening can stop.
Using the most common types of PSA tests currently available in the USA, the average, normal, healthy, 50- to 70-year-old male is generally believed to have a PSA of less than 4.0ng/ml. However, some men with cancers present with normal PSA values (<4.0ng/ml). Moreover, several conditions can result in an elevated PSA (>4.0ng/ml), of which cancer is only one: increases in PSA can be associated with infection (prostatitis) and benign enlargement of the prostate gland, know as benign prostatic hypertrophy [BPH]. BPH is not a malignant or a pre-cancerous condition.
Because of these limitations of the PSA test, several variations have been developed. These are used to help discriminate which patients might be at sufficient risk for prostate cancer so that a biopsy is recommended. These include:
◦ The free/total PSA test can help discriminate benign disease from malignancy in patients with PSA levels between 4-10ng/ml. This test measures the amount of PSA that is free in the blood stream, and compares it to the amount that is bound to proteins. The lower the ratio of free to total PSA, the greater the likelihood that the patient has prostate cancer as opposed to a benign condition.
◦ PSA velocity measures the speed at which PSA values increase over a period of time. Some physicians believe that use of PSA velocity allows them to tell more about the way prostate cancer may be developing in individual patients. Any change in PSA of more than 0.75ng/ml in a year, is highly suspicious for cancer and warrants a biopsy, even if the total PSA is well under a value of 4ng/ml.
◦ PSA density is a measure of the concentration of PSA in a man's prostate. It compares the value of the PSA to the size of the prostate. Neoplastic or cancerous prostate tissue produces more PSA than normal or benign tissue. To determine the PSA density, a PSA level is obtained and is divided by the volume of the prostate; a value >0.15ng/ml per gram of prostate tissue is considered worrisome for prostate cancer. In addition, a higher PSA density may be associated with more aggressive cancer.
◦ Prostate Health Index (PHI): This test utilizes several different types of PSa blood tests to calculate a risk of having cancer. Likewise, the 4K test looks at different types of proteins to help identify men at greater risk of having prostate cancer.
For men with more aggressive prostate cancer, the key to curing it is to diagnose it when it is localized. Fortunately, many men with localized cancer can be cured with either surgery or radiation or active surveillance, in which the cancer is followed and treatment is used when there is progression of the disease to a more threatening condition. Again, it is important that each patient have a thorough discussion with his physician about prostate cancer screening and be involved in the decision making process as to whether to proceed with it or not. For men who have questions about prostate cancer screening and PSA, the urologists at UMass are available for consultation.