Overview
The prostate is a glandular organ present only in males. Only men develop prostate cancer.
The prostate is normally about 3 cm long (slightly more than 1 inch) and lies at the neck of the bladder and in front of the rectum.
Almost all prostate cancers arise from the secretory glandular cells in the prostate. Cancer arising from a glandular cell is known as adenocarcinoma. Therefore, almost all prostatic cancers are prostatic adenocarcinomas.
In the United States, cancer of the prostate is a common malignant cancer in men, second only to lung cancer. About 200,000 new cases are diagnosed each year, and about 30,000 men die of the disease each year.
Causes
The cause of prostate cancer is unknown, but hormonal, genetic, environmental, and dietary factors are thought to play roles. The following risk factors have been linked with development of this condition:
- Age: There is a strong correlation between increasing age and developing prostate cancer. The incidence of prostate cancer increases steadily from fewer than 1 in 100,000 for men aged 40 years to 1146 per 100,000 in men aged 85 years. The median age at diagnosis of prostate cancer is 70.5 years. More than 80% of prostate cancers are diagnosed in men older than 65 years. Autopsy records indicate that 70% of men older than 90 years have at least one region of cancer in their prostate.
- Race: African American men are 1.5-2 times more likely than white men to develop prostate cancer. African American men also appear to develop prostate cancer at an earlier age.
- Genetic factors: Men who have a history of prostate cancer in their family, especially if it was a first-degree relative such as a father or brother, are at an increased risk. This risk may be 2-3 times greater than the risk for men without a family history of the disease.
- Diet: A diet high in fat has been associated with an increased risk of prostate cancer.
- Chemical agents: Exposure to chemicals such as cadmium has been implicated in the development of prostate cancer.
There is no proven link between frequency of sexual activity and prostate cancer risk.
Symptoms
Most men with prostate cancer have no symptoms. This is particularly true of early prostate cancer.
- Most prostate cancers are discovered incidentally when a digital rectal exam is performed.
- A digital rectal exam is part of a thorough regular health examination. Digital refers to finger.
- During the digital rectal exam, the examiner inserts a gloved and lubricated finger in the rectum to feel the prostate for abnormalities.
Symptoms usually appear when the tumor causes some degree of urinary blockage at the bladder neck or the urethra.
- The usual symptoms include difficulty in starting and stopping the urinary stream, increase in frequency of urination, and pain while urinating.
- The urinary stream may be diminished (urinary retention), or it may simply dribble out.
- Even after urination, there is a sense of bladder fullness because the bladder has not been fully emptied.
Despite these symptoms, many men do not seek medical care until the cancer has spread. Symptoms of metastatic disease include fatigue, malaise, and weight loss. Spread to the bones causes deep bone pain, especially in the hips and back, and bone fractures from weakening of the bone.
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