Prostate cancer usually progresses slowly and produces no symptoms in its initial stages. Warning signs may eventually include difficult or painful urination; frequent urination, especially at night; and blood in the urine or semen.
Pain in the lower back, pelvis, or upper thighs may signal that prostate cancer cells have spread to the ribs, pelvis, and other bones. All these symptoms, however, may have other causes, such as infection and prostate enlargement, which are a natural result of the aging process.
Many doctors perform screening tests for prostate cancer during regular physical exams in order to identify the disease in its earliest—and most curable—stages. Doctors perform a digital rectal examination, in which the physician uses a gloved finger to gently check the smoothness of the rectal lining. If cancer is present, a physician may feel a nodule or other prostate irregularity. Another screening test, called the prostate-specific antigen (PSA) test, measures levels of a protein called prostate-specific antigen in the blood. Prostate cancer cells overproduce this protein, causing an elevation of PSA levels in blood. If screening tests indicate cancer is present, a physician will usually perform a biopsy, in which a tissue sample is removed from the prostate and examined under a microscope. The American Cancer Society recommends that men aged 50 years and older should have an annual digital rectal exam and PSA test. Men who have a high risk for the disease (blacks or those with a family history of prostate cancer) should talk to their doctors about starting annual screening tests at a younger age.