Transrectal ultrasound
Transrectal ultrasound (TRUS) uses sound waves to create an image of the prostate on a computer screen.
Sound waves are released from a small probe placed in the patient's rectum. The sound waves create echoes as they enter the prostate. The same rectal probe detects the echoes that bounce back from the prostate and a computer translates the pattern of echoes into a picture.
Because prostate tumours and normal prostate tissue often reflect sound waves differently, this test may be useful in detecting tumours, even those which might be too small or located in areas of the gland that cannot be felt by DE. The procedure is essentially painless and takes about 10-20 minutes.
TRUS is useful when the PSA or DRE indicates an abnormality, to guide the biopsy needle into exactly the right area of the prostate.
The prostate biopsy
A biopsy is a surgical procedure that removes a sample of tissue for examination. A core needle biopsy is the main method used to diagnose prostate cancer. Under transcrectal ultrasound guidance a doctor inserts a narrow needle through the wall of the rectum into the area of the prostate gland that appears abnormal. The needle then removes a cylinder of tissue, which is then tested. The procedure takes about half an hour and causes little discomfort.
When prostate cancer is affirmed
If cancer is found in a prostate biopsy, it is graded in order to estimate how fast it is likely to grow and spread. Prostate cancers are graded according to how closely they look like normal prostate tissue.
The most commonly used prostate cancer grading system is called the Gleason system. This system assigns a Gleason grade ranging from 1 through 5 based on how much the arrangement of the cancer cells mimics the way normal prostate cells from glands. If the cancer cell clusters resemble the small, regular, evenly spaced glands of normal prostate tissue, a grade of 1 is assigned. If the cancer lacks these features and its cells seem to spread haphazardly through the prostate, it is a grade 5 tumour.
Cancers with a high Gleason score are more likely to have already spread beyond the prostate gland at the time they are detected. Therefore, the Gleason score along with the blood PSA level and DRE is useful in considering treatment options.
Staging prostate cancer
If the prostate biopsy finds a cancer, more tests are done to find out how far the cancer has spread. This is called staging. The stage of a cancer is the most important factor in choosing treatment options.
Physical examination
The physical exam, especially the digital rectal examination, is an important part of prostate cancer staging. The DRE can tell whether the cancer is limited to one side of the prostate, whether it has spread to the other side as well, or if it has spread beyond the prostate gland.
Imaging tests used for prostate cancer staging
Computed tomography
Commonly known as a CT or CAT scan, this test uses an x-ray beam to create a series of pictures of your body from any angles. A computer combines the information from all these pictures to produce a detailed cross-sectional image. This may reveal abnormally enlarged lymph nodes. Lymph nodes are a network of bean-sized collections of white blood cells that fight infection. Some prostate cancers spread to nearby lymph nodes, called pelvic lymph nodes. Enlarged pelvic lymph nodes could be a sign of spreading cancer, or could mean that your body is fighting an infection.
Magnetic resonance imaging (MRI)
MRI uses magnetic fields to create detailed cross-sectional pictures of selected areas of your body. These pictures can show abnormal areas of bones or lymph nodes that suggest cancer may have spread from the prostate.
Radionuclide bone scan
This procedure helps show whether the cancer has spread from the prostate gland to bones. The patient receives an injection of radioactive material. This low level of radiation does not cause any side effects. The radioactive substance is attracted to diseased bone cells throughout the entire skeleton. Areas of diseased bone will be seen on the bone scan image as dense, gray areas, called 'hot spots'.
Lymph node biopsy
This procedure is done to find out if cancer has spread from the prostate to nearby lymph nodes. Lymph nodes may be removed by the surgeon through an incision in the lower part of the abdomen and test them for cancer.
Another way is to take a sample of cells from a lymph node by using fine needle aspiration (FNA), in which CT scan images guide a long, thin needle into the lymph nodes. The syringe attached to the needle takes a small tissue sample from one of the lymph nodes. There is no incision, no scar, and the patient can return home a few hours after the procedure.
A surgeon may also use a laparoscope, which is a long, slender tube inserted into the abdomen through a very small incision. The laparoscope allows the surgeon to view lymph nodes near the prostate and remove these pelvic lymph nodes using special surgical instruments operated through the laparoscope.
The TNM staging system
While there are several different staging systems for prostate cancer, the most commonly used system is the TNM system. It describes the extent of the primary tumour (T stage), the absence of spread to nearby lymph nodes (N stage), and the absence or presence of distant metastasis (M stage).
Side effects of prostate cancer treatments
Incontinence
Incontinence is the inability to control the urine stream, resulting in leakage or dribbling of urine. The patient may have urine leakage when coughing, laughing, sneezing, or exercising. Treatment of incontinence depends on its type, cause, and severity. Options include exercises to strengthen bladder muscles, biofeedback, medications, and additional surgery.
Normal bladder control returns for many patients within several weeks or months after radical prostatectomy. Mild stress incontinence may persist permanently after surgery in up to 35 per cent of men.
Impotence
Impotence, also known as erectile dysfunction, is an inability to get an erection of the penis. The nerves that allow men to get erections may be damaged or removed by radical prostatectomy. Radiation therapy and cryosurgery can also cause damage to these nerves. However, during the first 3 to 12 months after radical prostatectomy, most men will not be able to get a spontaneous erection.
Side effects of cryosurgery
Freezing can damage nerves near the prostate and cause impotence and incontinence. These complications occur about as often after cryosurgery as they do after radical prostatectomy. In addition, freezing may damage the bladder and intestines, leading to pain, a burning sensation, and the need to empty the bladder and bowels often. About 50 per cent of men notice swelling of their penis and scrotum after cryosurgery, usually lasting a couple of weeks.
Side effects of radiation therapy
These may include diarrhoea with or without blood in the stool, and an irritated large intestine. Occasionally, normal bowel function does not return after treatment is stopped. Both during and after treatment, other side effects may include frequent urination, burning sensation while urinating and blood in the urine. Radiation therapy may also cause a feeling of fatigue that may not disappear until a month or two after treatment stops. Impotence usually does not occur right after radiation therapy but gradually develops over one or more years.
Side effects of chemotherapy
The side effects of chemotherapy depend on the type of drugs, the amount taken, and the length of treatment. Temporary side effects might include nausea and vomiting, loss of appetite, loss of hair, and mouth sores. Because chemotherapy can damage the blood-producing cells of the bone marrow, patients may have low blood cell counts. This can result in an increased change of infection. Most side effects, however, disappear once treatment is stopped.
Side effects of hormone therapy
- Hot flashes similar to those experienced by women in menopause, sometimes controllable with other drugs such as Megace.
- Breast enlargement, which may be prevented by treatment with radiation to the breasts prior to the start of the hormone blockade treatments.
- Impotence-varying degrees are experienced. Generally, potency returns hormone therapy is discontinued. Actually, loss of libido is experienced more often than impotency.
- Other possible side effects include, anaemia, weight gain, loss of muscle mass, loss of body hair, and diarrhoea.
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