Prostate Cancer Diagnosis
Prostate cancer testing is used to diagnose this potentially curable disease in men who would die prematurely if they have cancer and it is not found early.
For nearly 80 percent of men with prostate cancer, the disease is diagnosed early, in the local or regional stages. The five-year survival rate for these men is 100 percent. According to the American Cancer Society, the survival rate for all men with prostate cancer has increased from 67 percent to 92 percent over the past 20 years, primarily because men are being diagnosed at earlier stages than in the past.
The American Cancer Society recommends annual screening for all men over the age of 50 who have a life expectancy of at least 10 years. Annual screening consists of a prostate-specific antigen (PSA) test and a digital rectal exam (DRE).
Men who are at higher-than-average risk—including African American men and men with a family history of prostate cancer—should begin annual screening at age 40.
The American Cancer Society also recommends that all men who have a PSA score above 10 ng/mL should undergo a prostate biopsy. A PSA level greater than or equal to 4.0 ng/mL indicates the possibility of cancer. However, abnormal results alone are not sufficient to diagnose prostate cancer. For example, a non-cancerous, common condition called benign prostatic hyperplasia can also cause elevated PSA levels.
The following tests are used to diagnose prostate cancer.
Normal PSA levels in men are determined using statistical methods, usually defined as any level less than 2 standard deviations above the average. In men under 60 years of age, this number is 2.5 ng/mL, while in men over 60 it is 4.0 ng/mL.
Abnormal PSA results are those that are persistently elevated for up to three months of repeat testing. There is increasing evidence that men whose PSA levels are within the normal range but increase by 0.5 ng/mL for two to three consecutive years could also be at higher risk for cancer.
Free PSA Levels
The free PSA test is usually ordered only if the total PSA is elevated. It will help determine if further diagnostic tests are needed. This test is a subset of the total PSA. The free PSA level is divided by the total level to get a percent free PSA. The lower the percent free, the higher the prostate cancer risk. A result less than 15 percent means you have a higher risk for cancer. It is not clear that a low percent free PSA with a normal total PSA is a significant risk by itself.
Complexed PSA Levels
This is a relatively new blood test being investigated to see if it will help increase the accuracy of the total PSA test for cancer detection. It is not yet known if accuracy is improved with this test.
Urinary PCA3 Testing
This is a test for proteins in the urine after vigorous prostate massage thought to improve the accuracy of total/free PSA testing. Although available, this test has not been thoroughly reviewed in clinical trials to determine its accuracy in improving cancer detection. It can be used as an additional factor to recommend biopsy in addition to total/free PSA changes in men who have had prior biopsies without evidence of cancer. But it is not a stand-alone test, and it requires further study.
The urologist’s exam of the prostate is to assess the texture of the gland. Firm areas of the prostate, or nodules, significantly increase the likelihood of prostate cancer. Differences in size of the prostate overall, or even one side versus the other, have not been associated with increased cancer risk. Optimal prostate cancer detection requires the use of DRE along with PSA testing; neither one alone is enough.
Transrectal Ultrasound (TRUS)
TRUS is no longer used as a screening test for prostate cancer. This procedure requires using a probe that is inserted into the rectum. It is used to perform a prostate biopsy. If areas of concern for cancer are seen, they are sampled. (See biopsy information below).
Biopsy remains the only way to effectively diagnose prostate cancer. (Read more here.)