The prostate gland is a muscular male reproductive organ/gland surrounding the urethra just beneath the bladder and whose main function is to secrete prostate fluid, one of the components of semen. The prostate gland muscles, which are involuntary, help propel this seminal fluid into the urethra during ejaculation . It weighs about 20grams.
During ejaculation, millions of sperm move from the testes through the vas deferens into the area of the prostate. At this point, the prostate contracts, closing off the opening between the bladder and the urethra, releasing fluid into the urethra and pushing semen on through.
The fluid excreted by the prostate makes up about one-third of the total volume of semen and contains various enzymes, zinc and citric acid. Though prostate fluid is slightly acidic, another fluid in semen, made by the seminal vesicles, leaves semen slightly alkaline. This alkalinity helps protect sperm and prolong their life after they are deposited in the acidic environment of the vagina. One component of prostate fluid, an enzyme called Prostate Specific Antigen (PSA) also aids in the success of sperm by liquefying semen that has thickened after ejaculation. This thinning action allows sperm to swim more freely.
The prostate can become a problem in three major ways: enlargement, infection, and cancer. As a man ages, the prostate tends to enlarge. Because the urethra runs through the prostate, an enlarged prostate tends to cause difficulty with urination–men may experience incomplete bladder emptying, urinary frequency or hesitancy, or frequent awakening at night to urinate. The prostate can become infected, causing symptoms of a urinary tract infection: pain with urination, urinary frequency or urgency, blood in the urine, and sometimes fevers. The prostate can also develop cancer.
The prostate glands require male hormones, known as androgens, to work properly. These include testosterone, which is made in the testes; dehydroepiandrosterone, made in the adrenal glands; and dihydrotestosterone, which is converted from testosterone within the prostate itself. Androgens are also responsible for secondary sex characteristics such as facial hair and increased muscle mass.
BENIGN PROSTATE HYPERPLASIA (BPH).
More than half of men in their 60s suffer from a growth of the prostate called Benign Prostatic Hyperplasia (BPH). By age 70 or 80, a man’s chance of suffering BPH jumps to 90 percent. Symptoms include frequent urination, dribbling/leaking urine and a stuttered/weak stream or hesitancy (taking a while to get started). If the prostate grows too large, it may constrict the urethra and impede the flow of urine, making urination difficult and painful and, in extreme cases, completely impossible.
BPH can easily be managed using medication (using alpha blockers and/or DHT blockers) or minimally invasive outpatient procedures followed by insertion of a temporary stent to allow normal urination. However, in extreme cases, the entire prostate may have to be surgically removed as a last resort.
Urinary frequency due to bladder spasm, commonly seen in older men, may be confused with prostatic hyperplasia. Statistical observations suggest that a diet low in fat and red meat and high in protein and vegetables could protect against BPH.
Life-style changes to improve the quality of urination include urinating in the sitting position. This reduces the amount of residual volume in the bladder, increases the urinary flow rate and decreases the voiding time.
Benign prostate enlargement can sometimes lead to complications such as a urinary tract infection (UTI) or acute urinary retention. Serious complications are rare.
Prostate cancer is classified as an adenocarcinoma (glandular cancer), that begins when normal semen-secreting prostate gland cells mutate into cancer cells. It is most common is the peripheral zone of the prostate gland.
Initially, small clumps of cancer cells remain confined to otherwise normal prostate glands, a condition known as carcinoma in situ or prostatic intraepithelial neoplasia (PIN). Over time, these cancer cells multiply and spread to the surrounding prostate tissue forming a tumor. The tumor may eventually grow large enough to invade nearby organs such as the seminal vesicles or the rectum, or the tumor cells may travel in the bloodstream and lymphatic system.
Prostate cancer is considered a malignant tumor because it is a mass of cells that can invade other parts of the body, a process called metastasis. Prostate cancer most commonly metastasizes to the bones, lymph nodes, and may invade rectum, bladder and lower ureters after local progression.
While the exact cause(s) of prostate cancer remain unknown, some risk factors have been identified:
[li]Age – risk rises as you get older and most cases are diagnosed in men over 50 years of age. About 6 in 10 cases of prostate cancer are found in men over the age of 65.[/li][li]Ethnic group – prostate cancer is more common among men of African-Caribbean and African descent than in men of Asian descent. The reasons for these racial and ethnic differences are not clear.[/li][li]Family history – Prostate cancer seems to run in some families, which suggests that in some cases there may be an inherited or genetic factor. Having a brother or father who developed prostate cancer under the age of 60 seems to increase the risk of you developing it. The risk is higher for men who have a brother with the disease than for those with an affected father. The risk is much higher for men with several affected relatives, particularly if their relatives were young when the cancer was found. Research also shows that having a close female relative who developed breast cancer may also increase your risk of developing prostate cancer.[/li][li]Gene changes - Scientists have found several inherited gene changes that seem to raise prostate cancer risk, but they probably account for only a small percentage of cases overall. For example:[/li][/ul]
Inherited mutations of the BRCA1 or BRCA2 genes raise the risk of breast and ovarian cancers in some families. Mutations in these genes may also increase prostate cancer risk in some men.
Men with Lynch syndrome (also known as hereditary non-polyposis colorectal cancer, or HNPCC), a condition caused by inherited gene changes, have an increased risk for a number of cancers, including prostate cancer.
Other inherited gene changes can also raise a man’s risk of prostate cancer.
[li]Obesity – recent research suggests that there may be a link between obesity and prostate cancer.[/li][li]Exercise – men who regularly exercise have also been found to be at lower risk of developing prostate cancer.[/li][li]Diet – research is ongoing into the links between diet and prostate cancer. There is evidence that a diet high in calcium (through food or supplements) is linked to an increased risk of developing prostate cancer. Dairy foods (which are often high in calcium) might also increase risk. But most studies have not found such a link with the levels of calcium found in the average diet, and it’s important to note that calcium is known to have other important health benefits.[/li][/ul]
In addition, some research has shown that prostate cancer rates appear to be lower in men who eat foods containing certain nutrients such as lycopene, found in cooked tomatoes and other red fruit, and selenium, found in brazil nuts. The exact role of diet in prostate cancer is not clear, but several factors have been studied.
Men who eat a lot of red meat or high-fat dairy products appear to have a slightly higher chance of getting prostate cancer. These men also tend to eat fewer fruits and vegetables. Doctors aren’t sure which of these factors is responsible for raising the risk. Eating fats raises the amount of testosterone in the body, and testosterone speeds the growth of prostate cancer.
Lower blood levels of vitamin D may increase the risk of developing prostate cancer.
· Geography - Prostate cancer is most common in North America, northwestern Europe, Australia, and on Caribbean islands. It is less common in Asia, Africa, Central America, and South America. The reasons for this are not clear. More intensive screening in some developed countries probably accounts for at least part of this difference, but other factors such as lifestyle differences (diet, etc.) are likely to be important as well. For example, men of Asian descent living in the United States have a lower risk of prostate cancer than white Americans, but their risk is higher than that of men of similar backgrounds living in Asia.
· Smoking - Most studies have not found a link between smoking and prostate cancer risk. Some research has linked smoking to a possible small increase in the risk of death from prostate cancer, but this finding will need to be confirmed by other studies.
· Workplace exposures - There is some evidence that firefighters are exposed to substances (toxic combustion products) that may increase their risk of prostate cancer. Welders, battery manufacturers, rubber workers, and workers frequently exposed to the metal cadmium seem to be more likely to get prostate cancer.
· Inflammation of the prostate - Some studies have suggested that prostatitis (inflammation of the prostate gland) may be linked to an increased risk of prostate cancer, but other studies have not found such a link. . In particular, infection with the sexually transmitted infections chlamydia, gonorrhea, or syphilis seems to increase risk. Inflammation is often seen in samples of prostate tissue that also contain cancer. The link between the two is not yet clear, but this is an active area of research.
· Medication exposure- There are also some links between prostate cancer and medications, medical procedures, and medical conditions.Use of the cholesterol-lowering drugs known as statins may also decrease prostate cancer risk.
· Sexual factors - Several case-control studies have shown that having many lifetime sexual partners or starting sexual activity early in life substantially increases the risk of prostate cancer. This correlation suggests a sexually transmitted infection (STI) may cause some prostate cancer cases; however, many studies have unsuccessfully attempted to find such a link, especially when testing for STIs shortly before or after prostate cancer diagnosis. Studies testing for STIs a decade or more prior to prostate cancer diagnosis find a significant link between prostate cancer and various STIs (HPV-16, HPV-18 and HSV-2). This evidence could be explained by a yet-to-be-identified sexually transmitted infection and a long latency period between onset of infection and prostate cancer.
On the other hand, while the available evidence is weak, tentative results suggest that frequent ejaculation may decrease the risk of prostate cancer. A study, over eight years, showed that those that ejaculated most frequently (over 21 times per month on average) were less likely to get prostate cancer. The results were broadly similar to the findings of a smaller Australian study.
Prostate cancer does not normally cause symptoms until the cancer has grown large enough to put pressure on the urethra, resulting in problems associated with urination such as:
[li]needing to urinate more frequently, often during the night (nocturia)[/li][li]needing to rush to the toilet (urgency)[/li][li]difficulty in starting to pee (hesitancy)[/li][li]straining or taking a long time while urinating[/li][li]weak flow[/li][li]feeling that your bladder has not emptied fully[/li][li]blood in the urine (hematuria) or in semen[/li][li]painful urination (dysuria).[/li][li]Because the vas deferens deposits seminal fluid into the prostatic urethra, and secretions from the prostate gland itself are included in semen content, prostate cancer may also cause problems with sexual function and performance, such as difficulty achieving erection or painful ejaculation[/li][li]Leaking of urine when laughing or coughing (stress incontinence)[/li][li]Inability to urinate standing up[/li][/ul]
These are not symptoms of the cancer itself; rather, they are caused by the blockage from the cancer growth in the prostate. They can also be caused by an enlarged, noncancerous prostate or by a urinary tract infection.
Symptoms of advanced prostate cancer include;
· Loss of weight and appetite, fatigue, nausea, or vomiting
· Swelling of the lower extremities
[li]Advanced prostate cancer can spread to other parts of the body, causing additional symptoms such as bone pain, often in the bones of the spine, pelvis, or ribs. Spread of cancer into other bones such as the femur is usually to the proximal part of the bone. Prostate cancer in the spine can also compress the spinal cord, causing leg weakness and urinary and fecal incontinence.[/li][/ul]
· Weakness or paralysis in the lower limbs, often with constipation
Two initial tests are commonly used to look for prostate cancer in the absence of any symptoms. One is the digital rectal exam, in which a doctor feels the prostate through the rectum to find hard or lumpy areas known as nodules. The other is a blood test used to detect a substance made by the prostate called “prostate-specific antigen” (PSA). When used together, these tests can detect abnormalities that might suggest prostate cancer.
Prostate screening tests include:
· Digital rectal exam (DRE). During a DRE, your doctor inserts a gloved, lubricated finger into your rectum to examine your prostate, which is adjacent to the rectum. If your doctor finds any abnormalities in the texture, shape or size of your gland, you may need more tests. This will feel a little uncomfortable, but should not be painful.
Prostate cancer can make the gland hard and bumpy. However, in most cases, the cancer causes no changes to the gland and a DRE may not be able to detect the cancer.
DRE is useful in ruling out prostate enlargement caused by benign prostatic hyperplasia, as this causes the gland to feel firm and smooth
[li]Prostate-specific antigen (PSA) test. A blood sample is drawn from a vein in your arm and analyzed for PSA, a substance that’s naturally produced by your prostate gland. It’s normal for a small amount of PSA to be in your bloodstream. However, if a higher than normal level is found, it may be an indication of prostate infection, inflammation, enlargement or cancer.[/li][/ul]
The PSA test is a part of staging and can help tell if your cancer is likely to still be confined to the prostate gland. If your PSA level is very high, your cancer has probably spread beyond the prostate. This may affect your treatment options, since some forms of therapy (such as surgery and radiation) are not likely to be helpful if the cancer has spread to the lymph nodes, bones, or other organs.
PSA tests are also an important part of monitoring prostate cancer during and after treatment and when combined with DRE, helps identify prostate cancers at their earliest stages, but studies have disagreed whether these tests reduce the risk of dying of prostate cancer. For that reason, there is debate surrounding prostate cancer screening.
Neither of these initial tests for prostate cancer is perfect. Many men with a mildly elevated PSA do not have prostate cancer, and men with prostate cancer may have normal levels of PSA. Also, the digital rectal exam does not detect all prostate cancers, as it can only assess the back portion of the prostate gland.
[SIZE=5]· [SIZE=4]Transrectal ultrasound (TRUS).[/SIZE] F[SIZE=4]or this test, a small probe about the width of a finger is lubricated and inserted into your rectum. The probe gives off sound waves that enter the prostate and create echoes. The probe picks up the echoes, which a computer then turns into a black and white image of the prostate.[/SIZE][/SIZE]
[SIZE=4]The procedure often takes less than 10 minutes and is done at an outpatient clinic. You will feel some pressure when the probe is inserted, but it is usually not painful. The area may be numbed before the procedure.
TRUS is often used to look at the prostate when a man has a high PSA level or has an abnormal DRE result. It is also used during a prostate biopsy to guide the needles into the right area of the prostate.
TRUS is useful in other situations as well. It can be used to measure the size of the prostate gland, which can help determine the PSA density and may also affect which treatment options a man has. TRUS is also used as a guide during some forms of treatment such as internal radiation therapy or cryosurgery.
· [COLOR=rgb(0, 0, 255)]Prostate MRI. This has better soft tissue resolution than ultrasound.[/SIZE]
MRI, in those who are at low risk might help people choose active surveillance, in those who are at intermediate risk it may help with determining the stage of disease, while in those who are at high risk it might help find bone disease.
As of 2011, MRI is used to identify targets for prostate biopsy using fusion MRI with ultrasound (US) or MRI-guidance alone. In men who are candidates for active surveillance, fusion MR/US guided prostate biopsy detected 33% of cancers compared to 7% with standard ultrasound guided biopsy.
Prostate MRI is also used for surgical planning for men undergoing robotic prostatectomy. It has also shown to help surgeons decide whether to resect or spare the neurovascular bundle, determine return to urinary continence, and help assess surgical difficulty.
[SIZE=5]· [SIZE=4]Prostate biopsy[/SIZE][SIZE=4]. If certain symptoms or the results of early detection tests – a PSA blood test and/or DRE – are suggestive of prostate cancer, a prostate biopsy is indicated to confirm.[/SIZE][/SIZE]
[SIZE=4]A biopsy is a procedure in which a sample of body tissue is removed and then looked at under a microscope. A core needle biopsy is the main method used to diagnose prostate cancer. It is usually done by a urologist, a surgeon who treats cancers of the genital and urinary tract, which includes the prostate gland.
Using transrectal ultrasound to “see” the prostate gland, the doctor quickly inserts a thin, hollow needle through the wall of the rectum into the prostate. When the needle is pulled out it removes a small cylinder (core) of prostate tissue. This is repeated from 8 to18 times, but most urologists will take about 12 samples.
Though the procedure sounds painful, each biopsy usually causes only a brief uncomfortable sensation because it is done with a special spring-loaded biopsy instrument. The device inserts and removes the needle in a fraction of a second. The area will often be numbed first by injecting a local anesthetic alongside the prostate. The biopsy itself takes about 10 minutes. You will likely be given antibiotics to take before the biopsy and possibly for a day or 2 after to reduce the risk of infection.
For a few days after the procedure, you may feel some soreness in the area and will probably notice blood in your urine. You may also have some light bleeding from your rectum, especially if you have hemorrhoids. Many men also see some blood in their semen or have rust colored semen, which can last for several weeks after the biopsy, depending on how frequently you ejaculate.
Your biopsy samples will be sent to a lab, where a pathologist will look at them under a microscope to see if they contain cancer cells. If cancer is present, the pathologist will also grade it.
Even when taking many samples, biopsies can still sometimes miss a cancer if none of the biopsy needles pass through it. This is known as a false-negative result. It can miss up to one in five cancers, because the location of the cancer is unknown when it is carried out. The doctors can see the prostate using the ultrasound scan, but not the tumor(s) if they are present. If your doctor still strongly suspects you have prostate cancer (because your PSA level is very high, for example) a repeat biopsy might be needed to help be sure.[/SIZE]
[SIZE=4]…to be continued…[/SIZE]