The prostate gland is a small, solid gland roughly the size of a walnut, located behind the pubic bone. It is situated beneath the bladder, enclosing the first part of the urethra (water passage). Approximately 0.5ml of each ejaculate is fluid made by the prostate, containing a number of substances that nourish the sperm and are necessary for fertility. Two small pouches, the seminal vesicles, sit directly behind the prostate, and provide a further 2ml of ejaculatory fluid via small tubes that run through the prostate into the urethra, the ejaculatory ducts.
Cancer is a condition in which the growth of normal cells becomes uncontrolled for reasons not entirely understood. These cells continue to divide, creating a tumour which at first grows locally within the prostate, then may spread via the lymphatics or blood stream to more distant parts of the body. Prostate cancer most commonly affects the outer part of the gland, and is often slow growing over many years. It does not usually cause any symptoms until it has grown to a large size or spreads outside the prostate.
Prostate cancer is the 3rd most common cancer of Singaporean men, and sixth most common cause of from cancer in men.
One of the substances secreted into the ejaculate by the prostate, Prostate Specific Antigen (PSA), is made in larger amounts when prostate cells become cancerous, and can be measured in the blood. This is therefore used as a screening test for prostate cancer. It is not a perfect test however, and only around a third of men with an elevated PSA go on to have a diagnosis of prostate cancer made. Causes of an increased PSA other than cancer include:
The exact reason for prostate cells turning cancerous is not understood. A number of factors have been determined to identify those at higher risk of prostate cancer, and these include:
As prostate cancer affects the outer part of the gland most commonly (ie away from the urethra), it does not cause symptoms until it is advanced. As such it is often recommended to test asymptomatic men to ‘catch’ the disease early in its course when there is a greater chance of cure
Urinary symptoms are more often due to co-existing BPH
If prostate cancer spreads to other parts of the body, such as into the bones, it may cause symptoms in these areas such as pain.
These are used to determine how advanced or aggressive the cancer is and therefore the likelihood of cure with treatment such as surgery or radiotherapy.
The stage refers to how far the prostate cancer is spread.
Stage I: Cancer in this early stage is usually slow growing. The tumor cannot be felt and involves one-half of 1 side of the prostate or even less than that. PSA levels are low. The cancer cells are well differentiated, meaning they look like healthy cells
Stage II: The tumor is found only in the prostate. PSA levels are medium or low. Stage II prostate cancer is small but may have an increasing risk of growing and spreading.
Stage III: PSA levels are high, the tumor is growing, or the cancer is high grade. These all indicate a locally advanced cancer that is likely to grow and spread.
Stage IV: The cancer has spread beyond the prostate.
Prostate cancer is also given a grade called a Gleason score. This score is based on how much the cancer looks like healthy tissue when viewed under a microscope. Less aggressive tumors generally look more like healthy tissue. Tumors that are more aggressive are likely to grow and spread to other parts of the body. They look less like healthy tissue.
The Gleason scoring system is the most common prostate cancer grading system used. The pathologist looks at how the cancer cells are arranged in the prostate and assigns a score on a scale of 3 to 5 from 2 different locations. Cancer cells that look similar to healthy cells receive a low score. Cancer cells that look less like healthy cells or look more aggressive receive a higher score. To assign the numbers, the pathologist determines the main pattern of cell growth, which is the area where the cancer is most obvious and looks for another area of growth. The doctor then gives each area a score from 3 to 5. The scores are added together to come up with an overall score between 6 and 10.
Gleason scores of 5 or lower are not used. The lowest Gleason score is 6, which is a low-grade cancer. A Gleason score of 7 is a medium-grade cancer, and a score of 8, 9, or 10 is a high-grade cancer. A lower-grade cancer grows more slowly and is less likely to spread than a high-grade cancer.
Doctors look at the Gleason score in addition to stage to help plan treatment. For example, active surveillance may be an option for a patient with a small tumor, low PSA level, and a Gleason score of 6. Patients with a higher Gleason score may need treatment that is more intensive, even if the cancer is not large or has not spread.
There are many ways to treat cancer that is still confined to the prostate (stage I and II) and there is still no definite agreement as to which is the best. One of the reasons for this is that patients with early stage disease may live 10 years or more if no treatment is used, whereas in others the disease can be more serious and progress quickly. While we can generalize, it is impossible to predict with certainty for any one individual the course their particular cancer may take.
The first thing to note is that you should not feel pressured to make a decision. When prostate cancer is detected early, there is plenty of time to explore your options, and it is not uncommon for patients to take a few months to decide upon which treatment they would prefer.
If their cancer has been diagnosed very early or incidentally during transurethral prostate resection, a ‘wait and see’ policy may be chosen to assess if the cancer is growing quickly enough to warrant treatment. This does not mean do nothing, but involves a regime of regular PSA measurements and sometimes repeat prostate biopsies to monitor the cancer. If treatment is ultimately required, it may be in the form of curative treatment (such as surgery or radiotherapy), or control with hormonal therapy (particularly in the elderly or those with other medical conditions posing a more serious threat)
This is the traditional form of treatment for prostate cancer, and involves removal of the entire prostate gland along with the seminal vesicles and attached vas deferens. The urethra is then reattached to the bladder opening. For cancer confined within the prostate, this offers complete removal and subsequent analysis of the specimen for a more accurate prediction of cure. Following surgery the PSA drops to undetectable levels and is monitored closely. A rise in PSA after surgery is an indicator of very early cancer recurrence, and this may be further treated with radiotherapy in some patients.
During robot-assisted surgery, the instruments are attached to a mechanical device (robot) and inserted into your abdomen through several small incisions. The robot enhances the surgeons visualisation and replicates the surgeon’s hand movements with instruments that articulate in all dimensions and eliminates tremor, with a full three dimensional image of the anatomy. he surgeon sits at a console and uses hand controls to guide the robot to move the instruments. Robotic prostatectomy may allow the surgeon to make more-precise movements with surgical tools than is possible with traditional open or laparoscopic surgery.
Radiotherapy is the delivery of radiation beams at the prostate, aiming to destroy the cancerous cells, with minimal impact on surrounding normal structures (bladder, urethra and rectum). It can also be used in a palliative setting, directed at areas of cancer outside the prostate, eg for relief of bone pain due to cancer spread. Radiotherapy can be administered like an X-ray, by directing the beam from outside the body onto the prostate (external beam radiotherapy), or by inserting radioactive ‘seeds’ or needles into the prostate (brachytherapy). Following radiotherapy, the PSA slowly declines and is monitored to assess the success of treatment, although this can take up to 12-18 months.
This treatment is usually offered to patients in whom the cancer has spread beyond the prostate, eg to lymph glands or bone. Prostate cancer is partly driven by the male hormone, testosterone, which is made by the testicles. By stopping the production of testosterone, the cancer usually significantly shrinks in size throughout the body, and is held dormant for a period of time that may last many years. Ways to achieve this consist of either:
The effectiveness of treatment can be monitored by the PSA reading, which quickly drops in most patients. Side effects are those of a loss of the male hormone and are similar to the menopause experienced by women as they lose their female hormones. These may consist of fatigue, loss of libido, loss of erections, hot flushes, tender or enlarged breasts, loss of muscle bulk. Over time the bones may lose strength (osteoporosis) with increased risk of fracture, and therefore it is recommended to have regular bone density scans.
Hormonal therapy is not a cure, as with time the cancer begins to grow again despite the treatment, but is an effective control that in some patients can last for a long period of time.
Chemotherapy uses drugs to kill rapidly growing cells, including cancer cells. Chemotherapy in combination with hormonal therapy may be a treatment option for men with stage IV prostate cancer.
Chemotherapy may also be an option for cancers that don't respond to hormone therapy.
On top of the shock of being diagnosed with cancer, the array of possible treatment plans can leave patients feeling very confused as to which is most appropriate for them. Some patients feel surprised at being offered a choice of treatments and naturally feel inadequately prepared to make such an important decision. It is worthwhile seeking multiple consultations to discuss options, as well as second opinions from other specialists before coming to a decision.
A cancer diagnosis can be emotionally devastating but it's important to act fast.
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