Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (232 page)

Lotan Y, Roehrborn CG. Sensitivity and specificity of commonly available bladder tumor markers versus cytology: results of a comprehensive literature review and meta-analyses.
Urology.
2003;61:109–118.

PROSTATE CANCER

   Definition

   Prostate cancer is an adenocarcinoma of the prostate gland, most commonly occurring in the peripheral zone. There is a close association of the cancer with small clumps of cancer cells—carcinoma in situ or prostatic intraepithelial neoplasia (PIN)—although it has not been proven that PIN is the cancer precursor.

   Prostate cancer is generally so indolent that most men die of other causes before the disease becomes clinically advanced. However, globally it is the sixth leading cause of cancer deaths in men (second leading cause in the United States and first in the United Kingdom).

   Who Should Be Suspected?

   Prostate cancer tends to develop in men over age 50. In the early stage of the disease, most men have no symptoms directly linked to the cancer, but because the gland surrounds the prostatic urethra, changes in urinary function can occur with disease progression.

   As a presenting symptom, a change in urinary function (frequency, urgency, nocturia, hesitancy) is the most common, but benign prostatic hyperplasia (BPH) figures into the differential diagnosis and is usually the cause.

   Hematuria and hematospermia are uncommon symptoms but, if present, also are more likely to be caused by BPH. However, if occurring in older men, prostate cancer should be included in the differential diagnosis.

   Bone pain, often in the vertebrae, pelvis, or ribs, if present, would indicate metastatic disease.

   Early Detection

   The two methods for early detection of
suspected
prostate cancer are the digital rectal examination for asymmetric areas of induration or nodules on the posterior and lateral aspects of the prostate gland and measurement of serum prostate-specific antigen (PSA). About 20% of early detections occur through a suspicious digital rectal examination and the remaining 80% through a suspicious PSA test. A definitive diagnosis of prostate cancer by either method of early detection is established by a positive biopsy.

   Screening of
unsuspected
cases for prostate cancer via the PSA test is controversial. Because of the low specificity of elevated PSA levels for prostate cancer versus BPH or prostatitis, the benefits of screening are outweighed by the harms of unnecessary treatment. Screening is not recommended by the U.S. Preventive Services Task Force (Grade “D,” 2012) and the Centers for Disease Control and Prevention. The American Society of Clinical Oncology and the American College of Physicians discourage screening in those expected to live less than another 10–15 years. The American Urological Association recommends shared decision making in those from age 55 to 69 and no more often than every 2 years.