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.
- The prostate surrounds the urethra, which is a tubular structure that carries sperm and urine out of the penis.
- The prostate produces a thin, milky fluid that is added to the sperm at the time of ejaculation.
- Older men often have anenlarged prostate, which is a noncancerous condition called benign prostatic hypertrophy (BPH) that causes urinary symptoms.
Cancer occurs when normal cells undergo a transformation in which they grow and multiply without normal controls.
- As the cells multiply, they form a mass called a tumor.
- Tumors are cancerous only if they are malignant. This means that they invade neighboring tissues because of their uncontrolled growth.
- They may also travel to remote organs via the bloodstream.
- This process of invading and spreading to other organs is called metastasis.
- Tumors overwhelm surrounding tissues by invading their space and taking the oxygen and nutrients they need to survive and function.
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. According to American cancer society's most recent estimates, 192,280 new cases of prostate cancer would be diagnosed in 2009 and 27,360 would die from the disease.
The estimated lifetime risk of being diagnosed with the disease is 17.6% for whites and 20.6% for African Americans. The lifetime risk of death from prostate cancer similarly is 2.8% and 4.7% respectively. Because of these numbers, prostate cancer is likely to impact the lives of a significant proportion of men that are alive today.
Over the years, however, the death rate from this disease has shown a steady decline, and currently more than 2 million men in the U.S. are still alive after being diagnosed with prostate cancer at some point in their lives.
Most men with prostate cancer have no symptoms.
This is particularly true of early prostate cancer.
- Currently, most prostate cancers are discovered when a prostate biopsy is performed after a raised serum prostate specific antigen (S. PSA) blood test is noted. This test is frequently performed as a part of a health screening program.
- Sometimes, 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. If there are some hard or irregular areas in the prostate, the physician may request for a prostate biopsy to confirm or rule out the presence of prostate cancer (details regarding S. PSA and prostate biopsy are available in subsequent sections).
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.
Less common symptoms are blood in the urine (hematuria), painful ejaculation, orimpotence (inability to have an erection).
- These three symptoms are uncommon in early stages of the disease. They usually occur when the cancer is advanced.
- As the cancer advances to cause a greater blockage, bladder function may deteriorate further.
- Men with such advanced cancers sometimes experience recurring urinary tract infections.
These symptoms, by themselves, do not confirm the presence of prostate cancer in any single individual. Indeed, most, if not all, of these can occur in men with non-cancerous (benign) enlargement of the prostate, which is the more common form of prostate enlargement as compared to cancer.
However, the occurrence of these symptoms should prompt an evaluation by the physician to rule out cancer and provide appropriate treatment.
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.
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 one in 100,000 for men 40 years of age to 1,146 per 100,000 in men 85 years of age. The median age at diagnosis of prostate cancer is 70.5 years of age. More than 80% of prostate cancers are diagnosed in men older than 65 years of age. Autopsyrecords indicate that 70% of men older than 90 years of age have at least one region of cancer in their prostate.
- Race: African American men are 1.6 times more likely than white men to develop prostate cancer. They are also 2.4 times more likely to die from their disease as compared to white men of a similar age. Asian Americans, on the other hand, have a much lower chance of getting prostate cancer as compared to whites or African Americans. Although, these racial criteria have been used to study and describe the disease in the past, there is no defined biologic basis for this classification. In other words, these differences in diagnosis and death rates are more likely to reflect a difference in factors like environmental exposure, diet, lifestyle, and health-seeking behavior rather than any racial susceptibility to prostate cancer. Recent evidence, however, suggests that this disparity is progressively decreasing with high chances of complete cure in men undergoing treatment for organ-confined prostate cancer (cancer that is limited to within the prostate without spread outside the confines of the prostate gland) irrespective of race.
- 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 two to three times greater than the risk for men without a family history of the disease. Earlier age at diagnosis (<60 years of age) in a first-degree relative and disease affecting more than one relative also increases the risk for developing prostate cancer.
- Infection: Recent evidence has suggested the role of sexually transmitted infections as one of the causative factors for prostate cancer. People who have had sexually transmitted infections are reported as having 1.4 times greater chance of developing the disease as compared to the general population.
- 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 also some evidence to suggest that obesity leads to an increased risk of having more aggressive, larger prostate cancer, which results in a poorer outcome after treatment.
There is no proven link between frequency of sexual activity and prostate cancer risk.
Treatments for prostate cancer are effective in most men.
- They cause both short- and long-term side effects that may be difficult to accept.
- You and your life partner or family members should discuss your treatment options in detail with your urologist and other physicians.
- Make sure you understand which treatments are available, how effective each is likely to be, and what side effects can be expected.
- You must weigh all these choices carefully before making a decision about which course to pursue.