One in 11 men will develop prostatic cancer, the second most common neoplasm found in men older than age 55. (In black men, it’s the most prevalent cancer.) Adenocarcinoma is its most common form; sarcoma occurs only rarely. Most prostatic cancer originate in the posterior prostate gland; the rest, near the urethra.
Malignant prostatic tumors seldom result from the benign hyperplastic enlargement that commonly develops around the prostatic urethra in elderly men. Prostatic cancer seldom produces symptoms until it’s advanced.
Although androgens regulate prostate growth and function and may also speed tumor growth, no definite link between increased androgen levels and prostatic cancer has been found. When primary prostatic lesions metastasize, they typically invade the prostatic capsule and spread along the ejaculatory ducts in the space between the seminal vesicles or perivesicular fascia.
Prostatic cancer accounts for about 18% of all cancers. The incidence is highest in Blacks and lowest in Asians. Incidence also increases with age more rapidly than any other cancer.
Signs and symptoms
Manifestations of prostatic cancer appear only in the advanced stages and include signs and symptoms of urinary obstruction, such as difficulty initiating a urinary stream, dribbling, urine retention, unexplained cystitis and, rarely, hematuria.
A digital rectal examination that reveals a small, hard nodule may help diagnose prostatic cancer. The American Cancer Society advises a yearly digital examination for men older than age 40, a yearly blood test to detect prostate-specific antigen (PSA) in men older than age 50, and ultrasonography if abnormal results are found.
Biopsy confirms the diagnosis. PSA is produced by the normal neoplastic ductal epithelium of the prostate and secreted into the lumen; its concentration in the blood is proportional to the total prostate mass. PSA levels will be elevated in all patients with prostatic cancer, and serum acid phosphatase