- adenocarcinoma of the prostate
Prostate cancer is a tumor that grows in the prostate gland in men. The prostate gland is part of the reproductive system. It stores seminal fluid, the substance that mixes with sperm to form semen.
Prostate cancers range from highly aggressive, life-threatening tumors to small, slow-growing nodules. Some of these, though they meet the definition of malignancy under the microscope, never cause illness and are found only incidentally at surgery or autopsy.
What is going on in the body?
Normally, the prostate is a firm, walnut-shaped gland at the base of a man's bladder. It surrounds the urethra, the tube that carries urine from the bladder to the outside of the body. A man with prostate cancer has a tumor in the prostate gland. In some cases, prostate cancer can grow slowly for many years. Other times, it may grow rapidly and spread swiftly to other parts of the body. It may also spread its cells throughout the lymph system or bloodstream and along nerve pathways.
What are the causes and risks of the disease?
No one knows what causes prostate cancer. The male hormone testosterone stimulates the normal growth of the prostate gland, but unfortunately fuels the growth of prostate cancer cells as well. Viruses (such as HPV, or human papilloma virus) or chronic infections may contribute to prostate cancer.
Researchers have recently identified a gene that is linked to some cases of the disease. Unlike bladder cancer, prostate cancer has not yet been linked to common cancer-causing substances in the environmnet. Some of the risk factors for prostate cancer include:
- Advanced age. Prostate cancer is seen mostly in men over the age of 55.
- Diet. Fruits, vegetables, and fatty fish may lower a man's risk for prostate cancer. A high fat diet may increase the risk.
- Ethnic background. Prostate cancer occurs most often in African and northern European ethnic groups. It is less common in American Indian and Asian men.
- Family history of cancer. A man's risk is higher if his father or brother had prostate cancer.
Men who have had a vasectomy, who smoke, or who have been exposed to a metal called cadmium may also be at an increased risk.
What can be done to prevent the disease?
At this time, not all cases of prostate cancer are preventable. Good dietary choices, such as eating less fat and more fruits, vegetables, and fatty fish help lower a man's risk for prostate cancer.
The American Cancer Society (ACS), recommends that a digital rectal exam and a prostate-specific antigen (PSA) test be offered every year to men 50 years of age or older who have a life expectancy of at least 10 years. The ACS also recommends that screening start at the age of 45 years for African American men or men with a family history of prostate cancer.
How is the disease diagnosed?
Diagnosis of prostate cancer begins with a medical history and physical exam. The healthcare provider will do a digital rectal exam. This involves inserting a gloved finger into the man's rectum to feel the prostate. This exam helps tell whether a prostate is simply enlarged, which can explain urinary hesitancy or dribbling, or hether it has nodules or lumps which could be cancer.
PSA levels that are above the norm for a man's age and race can be due to any of a number of causes; however in general, the higher the level, the more likely that prostate cancer is the cause. It is important to note though that a prostate infection may elevate the PSA without the presence of cancer.
If prostate cancer is suspected, a biopsy may be done. During the biopsy, a needle is inserted into the prostate gland to obtain a small sample of tissue.
The healthcare provider may order a transrectal ultrasound. This test uses sound waves to examine the inside of the gland. It can be used to guide the healthcare provider during a biopsy. If several areas of the prostate are in question, a number of biopsies may be done.
The tissue is sent to a laboratory where it will be checked for cancer. Prostate cancer is graded (a measure of how aggressive the cells look under the microscope) and staged (a measure of how far the cancer has spread throughout the body.)
Cancer of the prostate is graded as a low score (Gleason score 2-4), intermediate score (Gleason score 5-7) and a high score (Gleason 8-10). A low score carries a very low risk of dying of prostate cancer and a high score carries a much higher risk of dying from prostate cancer. Staging prostate cancer is as follows:
- Stages A and B are cancers confined to the prostate gland.
- Stage C cancer has spread to other tissues near the prostate gland.
- Stage D cancer has spread to lymph nodes or sites in the body a distance away from the prostate
CT scans and bone scans help in staging. Sometimes staging only becomes clear at the time of surgery.
Long Term Effects
What are the long-term effects of the disease?
Long-term effects of prostate cancer depend on its grade and stage and the type of treatment used. Some men who have slow-growing cancer can be monitored without treatment. Others live for a long time even with prostate cancer that has spread to other sites in the body. Cancer that has spread is not curable in most cases and eventually causes death unless another illness occurs first.
What are the risks to others?
Prostate cancer is not contagious and poses no risk to others. Prostate cancer does run in families. Brothers or sons of men who develop cancer should be aware of their family history. They should be screened for the disease as they grow older, as recommended by the ACS.
What are the treatments for the disease?
The proper management of the many stages of prostate cancer is controversial. Depending on the grade and stage of the cancer, some options are as follows:
- brachytherapy which is high dose radiotherapy administered through small tubes temporarily placed in the prostate, followed by external radiation
- cryosurgery to freeze cancer cells
- external radiation to the prostate and pelvis
- hormone therapy
- intensity-modulated radiotherapy (IMRT) which is radiation delivered in a 3-dimensional fashion to limit radiation to surrounding tissues.
- surgery to remove part or all of the prostate and surrounding tissue
- surgical removal of the testicles to block testosterone production
- watchful waiting and monitoring only
Hormone is used mostly for men with advanced stage D disease. Hormone therapy includes use of the following:
- antiandrogens, such as flutamide (i.e., Eulexin and others) and bicalutamide (i.e., Casodex), that block the action of testosterone
- corticosteroids, such as prednisone
- GnRH agonists, also known as LHRH analogues, such as goserelin (i.e., Zoladex) and leuprolide (i.e., Lupron), which reduce the body's production of testosterone
- medicines that stop the production of testosterone, such as ketoconazole (i.e., Nizoral) and aminoglutethimide (i.e., Cytadren)
Treatment for men with prostate cancer that has spread through the body is usually with hormonal therapy or chemotherapy if they are healthy enough to take the treatments. If they are not, measures are taken to keep them as comfortable as possible. Often the prostate is not removed. A cure for advanced prostate cancer is not available, although research in this area continues.
What are the side effects of the treatments?
Following are some common side effects of radiation or surgery for prostate cancer:
- erectile dysfunction
- swelling of the extremities
- urinary incontinence
Occasionally, radiation or surgery may cause the following:
- bladder inflammation
- bone marrow suppression
- inflammation of the lining of the small intestine
- lowered blood counts
- severe swelling in the legs and feet
Depending on exact treatment, hormone therapy may cause the following conditions:
- erectile dysfunction
- a higher risk of blood clots in the leg
- osteoporosis, or bone thinning
- swelling in the breasts
Often given intravenously, chemotherapy
has certain common side effects, such as:
- bleeding disorders
- higher risk of infections
- lowered blood counts
- nausea and vomiting
- damage to organs such as the bone marrow, nervous system, heart, kidneys and liver
Cryosurgery or radiation implants can be painful and expensive. However, these treatments may preserve sexual function.
What happens after treatment for the disease?
After treatment, men are regularly monitored for side effects and a recurrence and progression of the cancer.
How is the disease monitored?
The following are used to monitor the disease:
- bone scans
- chest X-rays
- CT scans of the pelvis
- digital rectal exams
- PSA tests, which are sensitive and specific for recurrence of cancer
- ultrasound of the prostate
Any new or worsening symptoms should be reported to the healthcare provider.