Prostatic Cancer

Prostatic cancer is the second most common neoplasm found in men over age 50. Adenocarcinoma is its most common form; sarcoma occurs only rarely. Most prostatic carcinomas originate in the posterior prostate gland; the rest originate 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.

Causes

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. Incidence is highest in Blacks and lowest in Asians. Incidence also increases with age more rapidly than any other cancer.

Signs and symptoms

Diagnosis

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 over age 40, a yearly blood test to detect prostate-specific antigen (PSA) in men over age 50, and ultrasonography if abnormal results are found.

Biopsy confirms the diagnosis. PSA levels will be elevated in all, and serum acid phosphatase levels will be elevated in two-thirds of men with metastatic prostatic cancer.

Treatment

Treatment must be chosen carefully because prostatic cancer usually affects older men, who commonly have coexisting disorders, such as hypertension, diabetes, or cardiac disease.

Therapy varies with each stage of the disease and generally includes radiation, prostatectomy, orchiectomy to reduce androgen production, and hormone therapy with synthetic estrogen (diethylstilbestrol [DES]) and antiandrogens such as cyproterone, megestrol, and flutamide. Radical prostatectomy is usually effective for localized lesions.

Radiation therapy is used to cure some locally invasive lesions and to relieve pain from metastatic bone involvement.

If hormone therapy, surgery, and radiation therapy aren't feasible or successful, chemotherapy (using combinations of cyclophosphamide, doxorubicin, fluorouracil, cisplatin, etoposide, and vindesine) may be tried. However, current drug therapy offers little benefit. Combining several treatment methods may be most effective.

Prevention

No preventive measures are known. Adopting a vegetarian, low-fat diet or one that mimics the traditional Japanese diet may lower risk. Early identification (as opposed to prevention) is now possible by yearly screening of men over 40 or 50 years old through digital rectal examination (DRE) and PSA blood test.