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Prostate cancer is a disease in which cancer develops in the prostate, a gland important in male reproduction. Cancer occurs when cells that form the basic building blocks of the prostate multiply out of control. These cells may spread (metastasize) from the prostate to other parts of the body, especially the bones and lymph nodes. Prostate cancer can cause severe pain, weight loss, erectile dysfunction, difficulty urinating and can result in death.

Prostate cancer only occurs in men and develops most frequently in individuals over fifty years old. It is the second most common type of cancer in men and is responsible for more deaths than any cancer except for lung cancer. However, many men who develop prostate cancer never have symptoms, undergo no therapy, and die of unrelated illness. Many things, including diet, have been implicated in the development of prostate cancer but, as of 2005, it is not a preventable disease.

Prostate cancer is most often discovered by screening blood tests or by physical examination of the prostate gland by a health care provider. Confirmation of prostate cancer is typically accomplished by removing a piece of the prostate (biopsy) and examining it under a microscope. Further tests, such as x-rays and bone scans, may be performed to determine whether prostate cancer has spread.

Prostate cancer can be treated with surgery, hormone therapy, chemotherapy, radiation therapy, or a combination thereof. The age and underlying health of the individual, as well as the extent of spread, appearance under the microscope, and response of the cancer to initial treatment are important in determining the outcome of the disease.  Administrator note Since prostate cancer is a disease of older men, many men will die of other causes before the prostate cancer can spread or cause symptoms; this makes selecting treatment options difficult.

Prostate cancer
Specialty	Oncology, urology

The prostate

The prostate is an organ in the male reproductive system which helps make and store semen. The normal adult prostate is about the size of a walnut, is three centimers long, and weighs twenty grams. Administrator note It is located in the pelvis, beneath the bladder and in front of the rectum. It surrounds the upper part of the urethra, the tube that carries urine from the bladder during urination and semen during ejaculation. Administrator note Because of its location, diseases of the prostate may cause symptoms which affect urination, ejaculation, or defecation.

The prostate is composed of 30-50 small glands which create twenty percent of the fluid comprising semen. Administrator note These glands are formed by the cells which are mutated in prostate cancer. These cells require male hormones, known as androgens, to work properly. Androgens include testosterone, which is made in the testes, and dehydroepiandrosterone, made in the adrenal glands. These hormones are also responsible for male secondary sex characteristics such as facial hair and testicular growth.

Symptoms

Early stage prostate cancer does not usually cause symptoms. The majority of the time, it is diagnosed during the workup for an elevated PSA detected on a routine check-up.

Sometimes, however, prostate cancer causes symptoms which are more common in diseases such as benign prostatic hypertrophy. These include frequent urination, increased urination at night, difficulty initiating and maintaining a stream of urine, weak flow of urine, blood in the urine, and painful urination. Prostate cancer may also interfere with sexual function, causing difficulty achieving erection or painful ejaculation. Administrator note

More advanced prostate cancer may cause symptoms which result from spread of the disease to parts of the body outside of the pelvis. The most common symptom is bone pain from involvement of the bone with prostate cancer. This is often in the lower back, from spread of the tumor to the spine. Prostate cancer in the spine may also compress the spinal cord, resulting in weakness of the legs and urinary and fecal incontinence. Administrator note

Pathophysiology

Cancer is a group of many related diseases. These diseases begin in cells, the body's basic unit of life. Cells have many important functions throughout the body. Normally, cells grow and divide to form new cells in an orderly way. They perform their functions for a while, and then they die (apoptosis). This process helps keep the body healthy. Sometimes, however, cells do not die. Instead, they keep dividing and creating new cells that the body does not need. They form a mass of tissue, called a growth or tumor.

Tumors can be benign or malignant:

• Benign tumors are not cancer. They can usually be removed, and in most cases, they do not come back. Cells from benign tumors do not spread to other parts of the body. Most important, benign tumors of the prostate are not a threat to life. Benign prostatic hyperplasia (BPH) is the abnormal growth of benign prostate cells. In BPH, the prostate grows larger and presses against the urethra and bladder, interfering with the normal flow of urine. More than half of the men in the United States between the ages of 60 and 70 and as many as 90 percent between the ages of 70 and 90 have symptoms of BPH. For some men, the symptoms may be severe enough to require treatment.

• Malignant tumors are cancer. Cells in these tumors are abnormal. They divide without control or order, and they do not die. They can invade and damage nearby tissues and organs. Also, cancer cells can break away from a malignant tumor and enter the bloodstream and lymphatic system. This is how cancer spreads from the original (primary) cancer site to form new (secondary) tumors in other organs. The spread of cancer is called metastasis.

When prostate cancer spreads (metastasizes) outside the prostate, cancer cells are often found in nearby lymph nodes. If the cancer has reached these nodes, it means that cancer cells may have spread to other parts of the body -- other lymph nodes and other organs, such as the bones, bladder, or rectum. When cancer spreads from its original location to another part of the body, the new tumor has the same kind of abnormal cells and the same name as the primary tumor. For example, if prostate cancer spreads to the bones, the cancer cells in the new tumor are prostate cancer cells. The disease is metastatic prostate cancer; it is not bone cancer.

Epidemiology

The risk of developing prostate cancer is related to genetics, age, race, diet, lifestyle, and medications. Prostate cancer only occurs in men, and is more common with advancing age. Prostate cancer is uncommon in men less than 45. The average age of patients at the time of diagnosis is 70. Administrator note

A genetic predisposition to prostate cancer is suggested by an increased incidence among certain racial groups, in identical twins of men with prostate cancer, and in men with certain genes. In the United States, prostate cancer affects black men more commonly than white or Hispanic men. Prostate cancer is more common and more deadly in black men. Administrator note Men who have a brother or father with prostate cancer are twice as likely to themselves develop prostate cancer. Administrator note Scandinavian twin studies suggest that forty percent of prostate cancer risk can be explained by inherited factors. Administrator note There is no one single gene which is responsible for prostate cancer, however. Many different genes have been implicated. Two genes (BRCA1 and BRCA2) that are important risk factors for ovarian cancer and breast cancer in women have also been implicated in prostate cancer. Administrator note

Several different foods, vitamins, and minerals contribute to prostate cancer risk. The strongest link has been found between increased consumption of animal fat and increased risk for prostate cancer. Decreased intake of fruits and vegetables is also related to an increase in prostate cancer risk. Indeed this seems to be related to increased intake of alpha-linoleic acid (found in animal fat) at the expense of linoleic acid (found in vegetable oils). Less firm connections have been found between an increased risk for prostate cancer and a decreased intake of vitamin E (found in green leafy vegetables), lycopene (found in tomatoes), omega-3 fatty acids (found in fatty fishes like salmon), and the mineral selenium. Lower blood levels of vitamin D also may increase risk. Less ultraviolet radiation (UV) exposure also increases risk; because UV radiation is partly responsible for increasing levels of vitamin D in the blood, this further supports vitamin D's role in the development of prostate cancer. Administrator note

There are links between prostate cancer and medications, medical procedures, and medical conditions. Daily use of non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen, and naproxen sodium potentially decrease prostate cancer risk. Administrator note The group of cholesterol lowering drugs collectively known as the statins (eg atorvastatin) may lower prostate cancer risk. Administrator note Sterilization by vasectomy may increase the risk of prostate cancer, though there are conflicting data. Administrator note Men who are circumcised may have decreased rates of prostate cancer. Administrator note Increased ejaculation frequency also may decrease the chance for prostate cancer; one study showed that men who had five episodes of ejaculation a week in their 20s had a decreased rate of prostate cancer. Administrator note Infection or inflammation of the prostate, prostatitis, may increase the chance for prostate cancer. In particular, infection with the sexually-transmitted infections chlamydia, gonorrhea, and syphilis seem to increase risk. Administrator note Finally, obesity Administrator note and elevated blood levels of testosterone Administrator note may also increase the risk for prostate cancer.

Screening

Screening means looking for signs of disease in people who have no symptoms. So screening for prostate cancer is looking for early-stage disease when treatment may be more effective. The main screening tools for prostate cancer are the digital rectal examination (DRE) and the prostate–specific antigen (PSA) test. The DRE and PSA test cannot tell if you have cancer; they can only suggest the need for further tests. Some medical experts believe all men should be offered regular screening tests for prostate cancer. Other medical experts do not recommend screening.

• Digital rectal examination (DRE) -- During this procedure, the physician inserts a gloved, lubricated finger into the rectum in order to feel the size and shape of the prostate to find areas that are for hard or lumpy, which may indicate cancer. DRE can only detect abnormalities in one area of the prostate (the zone that can be felt through the rectum). Fortunately, this is where most prostate cancers arise.
• Blood test for prostate-specific antigen (PSA) -- a lab measures the levels of PSA in a blood sample. Under normal circumstances, PSA is not found in the blood, but levels lower than 4 ng/mL (nanograms per milliliter) are considered normal. Levels greater than 10 ng/mL are considered abnormal. PSA levels between 4 and 10 ng/mL are considered to be borderline. PSA tests for prostate cancer are a subject of some controversy among clinicians and researchers. This is because some men who have prostate cancer do not have elevated PSA (>4 ng/mL), while some men with elevated levels do not have prostate cancer. This is far from being a perfect test, but it is the best method currently and used commonly.

Elevated PSA levels can occur for many reasons. They may rise in men who have prostate cancer, benign prostate hyperplasia (BPH), or an infection in the prostate (prostatitis). To maximize the accuracy of a PSA test: (1) don't ejaculate for 2 days prior to having a PSA test as this can raise PSA levels, and (2)inform your physician if you are taking finasteride (marketed as Proscar or Propecia) or dutasteride (marketed as Avodart). These drugs, used to treat BPH and baldness affect the metabolism of testosterone throughout your body and will likely lower your PSA levels. Also, (3) the DRE needs to be performed after drawing blood for the PSA test, as palpation of the prostate can stimulate it to produce PSA and lead to elevated PSA levels in the serum. Some herbal supplements can also affect PSA levels. Discuss any supplements you are taking with your physician prior to having a PSA test.

The most recent trend is to consider the rate of change of the PSA level as an indication of the risk of cancer. This requires at least two PSA tests be done over a period of time. Abnormal DRE or high serum PSA levels are reasons for a medical follow up. The results of these tests will help to determine whether further tests are necessary to check for cancer.

When the total PSA blood test is in the grey zone (between 4 and 10 ng/mL) and the DRE is normal, the percentage of free PSA (unbound to other proteins) in the blood is used to distinguish between BPH and prostate cancer. A low value for percent-free PSA indicates a higher probability of prostate cancer.

Currently, a biopsy is the only procedure that can definitively diagnose prostate cancer. It is performed when digital rectal examination shows abnormalities or a patient has high total PSA in the serum. A biopsy gun inserts and removes hollow core needles (usually three to six for each side of the prostate) in less than a second. The needles are very fine and remove only small cores of tissue. In this way, small 'samples' of the prostate are removed. The tissue samples are then examined under a microscope to determine if cancer cells are present and to evaluate the extent of the cancer. Some men have reported that this is the most physically uncomfortable part of their experience of being diagnosed with prostate cancer. (Patients can request that an appropriate anesthetic be used.)

Diagnosis

If a man has symptoms or test results that suggest prostate cancer, his doctor asks about his personal and family medical history, performs a physical exam, and may order laboratory tests. The exams and tests may include a digital rectal exam, a urine test to check for blood or infection, and a blood test to measure PSA. In some cases, the doctor also may check the level of prostatic acid phosphatase (PAP) in the blood, especially if the results of the PSA indicate there might be a problem.

The doctor may order exams to learn more about the cause of the symptoms. These may include:

• Transrectal ultrasonography -- sound waves that cannot be heard by humans (ultrasound) are sent out by a probe inserted into the rectum. The waves bounce off the prostate, and a computer uses the echoes to create a picture called a sonogram.
• Intravenous pyelogram -- a series of x-rays of the organs of the urinary tract.
• Cystoscopy -- a procedure in which a doctor looks into the urethra and bladder through a thin, lighted tube.

If test results suggest that cancer may be present, the man will need to have a biopsy. During a biopsy, the doctor removes tissue samples from the prostate, usually with a needle. A pathologist looks at the tissue under a microscope to check for cancer cells. If cancer is present, the pathologist usually reports the grade of the tumor. The grade tells how much the tumor tissue differs from normal prostate tissue and suggests how fast the tumor is likely to grow. The most common method of grading prostate cancer, called the Gleason system, uses scores of 2 to 10, with 10 indicating the most aberrant growing and 'cancerous' samples. The pathologist assigns a number between 1 and 5 to the most common pattern observed under the microscope. The second most common pattern is also assigned a number. The sum of these numbers makes up the Gleason score. Another system uses G1 through G4. It is important that the pathologist grading the tumor have a lot of experience looking at prostate tumors, as the grade of the tumor is one of the major factors in determining the treatment recommendation. This is because tumors with higher scores or grades are more likely to grow and spread than tumors with lower scores.

If the physical exam and test results do not suggest cancer, the doctor may recommend treatment for benign prostatic hypertrophy.

Stages

An important part of the evaluation of prostate cancer is determination of the stage, or how far the cancer has spread. The most common system is the TNM system, which evaluates the size of the tumor, the number of involved lymph nodes, and any other metastasis. As with many other cancers, these are often grouped into four stages (I–IV). The Whitmore-Jewett stage is another method sometimes used. The purpose of staging is to help determine prognosis and to assist in selecting therapies; a good staging system will have similar characteristics for most cancers at a given stage.

Treatment

Treatment for prostate cancer depends on the stage of the disease and the grade of the tumor (which indicates how abnormal the cells look, and how likely they are to grow or spread). Other important factors in planning treatment are the man's age and general health and his feelings about the treatments and their possible side effects.

Treatment for prostate cancer may involve watchful waiting, surgery, radiation therapy, or hormonal therapy. Some patients receive a combination of therapies. The patient and his doctor may want to consider both the benefits and possible side effects of each option, especially the effects on sexual activity and urinary control, and other concerns about quality of life.

It is hard to limit the effects of treatment so that only cancer cells are removed or destroyed. Because healthy cells and tissues may be damaged, treatment often causes unwanted side effects. The side effects of cancer treatment depend mainly on the type and extent of the treatment. Also, each patient reacts differently.

During and after treatment, the doctor will continue to follow the patient. The doctor will examine the man regularly to be sure that the disease has not returned or progressed, and will decide what other medical care may be needed. Follow-up exams may include x-rays, scans, and lab tests, such as the PSA blood test.

Watchful waiting

If the doctor recommends watchful waiting, the man's health will be monitored closely, including frequent PSA monitoring, and he will be treated only if symptoms occur or worsen or if the rate of PSA rise is concerning. Watchful waiting may be suggested for some men who have prostate cancer that is found at an early stage and appears to be slow growing. Also, watchful waiting may be advised for older men or men with other serious medical problems. For these men, the risks and possible side effects of surgery, radiation therapy, or hormonal therapy may outweigh the possible benefits. Men with early stage prostate cancer are taking part in a study to determine when or whether treatment may be necessary and effective.

Although men who choose watchful waiting avoid the side effects of surgery and radiation, there can be some negative aspects to this choice. Watchful waiting may reduce the chance of controlling the disease before it spreads. Also, older men should keep in mind that it may be harder to manage surgery and radiation therapy as they age.

Some men may decide against watchful waiting because they feel they would be uncomfortable living with an untreated cancer, even one that appears to be growing slowly or not at all. A man who chooses watchful waiting but later becomes concerned or anxious should discuss his feelings with his doctor. A different treatment approach is nearly always available.

Surgery

Surgery is a common treatment for early stage prostate cancer. The doctor may remove all of the prostate (a type of surgery called radical prostatectomy) or only part of it. In some cases, the doctor can use a new technique known as nerve-sparing surgery. This type of surgery may save the nerves that control erection. However, men with large tumors or tumors that are very close to the nerves may not be able to have this surgery.

The doctor can describe the types of surgery and can discuss and compare their benefits and risks.

• In radical retropubic prostatectomy, the doctor removes the entire prostate and nearby lymph nodes through an incision in the abdomen.
• In radical perineal prostatectomy, the doctor removes the entire prostate through an incision between the scrotum and the anus. Nearby lymph nodes are sometimes removed through a separate incision in the abdomen.

Surgical removal of the prostate and surrounding tissue (radical prostatectomy) has long been recognized as one of the most effective forms of therapy for prostate cancer. A conventional radical prostatectomy involves an open incision across the abdomen. Robotic laparoscopic prostatectomy represents a major advance in the treatment of prostate cancer by offering men a less-invasive alternative to traditional surgery. The surgeon performs the same nerve-sparing procedure done in conventional laparoscopic prostatectomy, but with greater precision. The prostate, nearby lymph nodes, seminal vesicles and adjacent tissue are removed through the small incisions, which are closed with a few stitches.

• In transurethral resection of the prostate (TURP), the doctor removes part of the prostate with an instrument that is inserted through the urethra. The cancer is cut from the prostate by electricity passing through a small wire loop on the end of the instrument. This method is used mainly to remove tissue that blocks urine flow.

If the pathologist finds cancer cells in the lymph nodes, it is likely that the disease has spread to other parts of the body. Sometimes, lymph nodes are removed before doing a prostatectomy. If the prostate cancer has not spread to the lymph nodes, the doctor then removes the prostate. But if cancer has spread to the nodes, the doctor usually does not remove the prostate, but may suggest other treatment.

While the above was the standard of care through the 1980s and early 1990s recent Journal publications indicate that "Radical prostatectomy combined with early adjunctive hormonal therapy for patients with nodal metastasis is superior to all other forms of therapy and should be considered the standard of care. This approach provides survival rates comparable with patients with clinically organ-confined prostate cancer." Radical prostatectomy for the patient with locally advanced prostate cancer. Administrator note

Patients are often uncomfortable for the first few days after surgery. Pain usually can be controlled with medicine, and patients should discuss pain relief with the doctor or nurse. The patient will wear a catheter (a tube inserted into the urethra) to drain urine for 10 days to 3 weeks. The nurse or doctor will show the man how to care for the catheter. It is also common for patients to feel extremely tired or weak for a while. The length of time it takes to recover from an operation varies.

Surgery to remove the prostate can cause long-term problems, including impotence and/or fecal or urinary incontinence. Nerve-sparing surgery is an attempt to avoid the problem of impotence. When the doctor can use nerve-sparing surgery and the operation is fully successful, impotence may be only temporary or partial. Still, some men who have this procedure may be permanently impotent. Different men experience these side effects to be a greater or lesser problem. Men who have a prostatectomy no longer produce semen, so they have dry orgasms. Men who wish to father children may consider sperm banking or a sperm retrieval procedure.

Radiation therapy

Radiation therapy (also called radiotherapy) uses high-energy x-rays to kill cancer cells. Like surgery, radiation therapy is local therapy; it can affect cancer cells only in the treated area. In early stage prostate cancer, radiation can be used instead of surgery, or it may be used after surgery to destroy any cancer cells that may remain in the area. In advanced stages, it may be given to relieve pain or other problems.

Radiation may be directed at the body by a linear accelerator, or it may come from tiny radioactive seeds placed inside or near the tumor (internal or implant radiation, or brachytherapy). Men who receive radioactive seeds alone usually have small tumors. Some men with prostate cancer receive both kinds of radiation therapy.

For external radiation therapy, patients go to the hospital or clinic, usually 5 days a week for several weeks. Patients may stay in the hospital for a short time for implant radiation.

Radiation therapy may cause patients to become extremely tired, especially in the later weeks of treatment. Resting is important, but doctors usually encourage men to try to stay as active as they can. Some men may have diarrhea or frequent and uncomfortable urination.

When men with prostate cancer receive external radiation therapy, it is uncommon for the skin in the treated area to become red, dry, or tender, however there may be hair loss in the treated area. The loss is usually temporary.

Both types of radiation therapy may cause impotence in some men. While internal radiation therapy may cause temporary urinary incontinence, external radiation therapy causes temporary bowel inflammation. Long-term side effects from internal radiation therapy are uncommon.

External beam radiotherapy with curative intent for localised prostate cancer is frequently given with concurrent hormone ablation therapy. The indications for adding hormone therapy are currently (September 2005) in a state of flux, as is the recommended interval for such treatment. Generally, patients who are thought to have a significant (>15%) risk of lymph node involvement or spread beyond the prostate are given concurrent hormone ablation drugs. Oncologists give such treatment anywhere from 2 months to 3 years in overall duration.

External beam radiotherapy, prostate implant brachytherapy, and radical surgery all appear equally efficacious in curing localised prostate cancer.

Cryotherapy

Cryotherapy is another method of treating prostate cancer. Cryotherapy is the insertion of metal rods into the prostate and circulating liquid nitrogen through these rods. This process lowers the temperature to about minus 374° F. As the tissue freezes, the formation and expansion of ice crystals within the cancerous cells cause them to rupture and die. A catheter is placed inside the urethra and a warming solution is circulated to prevent damage to the urethra. Short term results have been good however long term results appear to suggest that it is not as effective as surgery or radiation. Additionally, impotence results from cryotherapy 90 percent of the time.

Hormonal therapy

Hormonal therapy keeps cancer cells from getting the male hormones they need to grow. It is called systemic therapy because it can affect cancer cells throughout the body. Systemic therapy is used to treat cancer that has spread. Sometimes this type of therapy is used to try to prevent the cancer from coming back after surgery or radiation treatment.

There are several forms of hormonal therapy:

• Orchiectomy is surgery to remove the testicles, which are the main source of male hormones.
• Drugs known as luteinizing hormone-releasing hormone (LHRH) agonists can prevent the testicles from producing testosterone. Examples are leuprolide, goserelin, and buserelin.
• Drugs known as antiandrogens can block the action of androgens. Two examples are flutamide and bicalutamide.
• Drugs that can prevent the adrenal glands from making androgens include ketoconazole and aminoglutethimide. These drugs are rarely used for this purpose.

After orchiectomy or treatment with an LHRH agonist, the body no longer gets testosterone from the testicles. However, the adrenal glands still produce small amounts of male hormones. Sometimes, the patient is also given an antiandrogen, which blocks the effect of any remaining male hormones. This combination of treatments is known as total androgen blockade (TAB), combined hormonal therapy (CHT), combined androgen blockade (CAB), or maximal androgen deprivation (MAD). Doctors do not know for sure whether total androgen blockade is more effective than orchiectomy or LH-RH agonist alone.

Prostate cancer that has spread to other parts of the body usually can be controlled with hormonal therapy for a period of time, often several years. Eventually, however, most prostate cancers are able to grow with very little or no male hormones. When this happens, hormonal therapy is no longer effective, and the doctor may suggest other forms of treatment that are under study.

The side effects of hormonal therapy depend largely on the type of treatment. Orchiectomy and LH-RH agonists often cause side effects such as impotence, hot flashes and loss of sexual desire. When first taken, an LH-RH agonist may make a patient's symptoms worse for a short time. This temporary problem is called "flare." Gradually, however, the treatment causes a man's testosterone level to fall. Without testosterone, tumor growth slows down and the patient's condition improves. (To prevent flare, the doctor may give the man an antiandrogen for a while along with the LH-RH agonist.) In some cases, men may be prescribed intermittent courses of hormone therapy, with careful monitoring by their doctor to determine when to begin the next course of treatment.

Antiandrogens can cause nausea, vomiting, diarrhea, or breast growth or tenderness. If used a long time, ketoconazole may cause liver problems, and aminoglutethimide can cause skin rashes. Men who receive total androgen blockade may experience more side effects than men who receive a single method of hormonal therapy. Any method of hormonal therapy that lowers androgen levels can contribute to weakening of the bones in older men.

Support for men with prostate cancer

Living with a serious disease such as cancer is not easy. Some people find they need help coping with the emotional as well as the practical aspects of their disease. Patients often get together in support groups, where they can share what they have learned about coping with their disease and the effects of treatment. Patients may want to talk with a member of their health care team about finding a support group.

People living with cancer may worry about caring for their families, keeping their jobs, or continuing daily activities. Concerns about treatments and managing side effects, hospital stays, and medical bills are also common. Doctors, nurses, dietitians and other members of the health care team can answer questions about treatment, working, or other activities. Meeting with a social worker, counselor, or member of the clergy can be helpful to those who want to talk about their feelings or discuss their concerns. Often, a social worker can suggest resources for help with rehabilitation, emotional support, financial aid, transportation, or home care.

It is natural for a man and his partner to be concerned about the effects of prostate cancer and its treatment on their sexual relationship. They may want to talk with the doctor about possible side effects and whether these are likely to be temporary or permanent. Whatever the outlook, it is usually helpful for patients and their partners to talk about their concerns and help one another find ways to be intimate during and after treatment.

Current research

Many types of clinical trials on prostate cancer are being conducted. These include studies of ways to prevent, detect, diagnose, and treat prostate cancer; studies of the psychological effects of the disease; and studies of ways to improve comfort and quality of life.

Causes

Although several risk factors for prostate cancer are known, it is still not sure why one man develops the disease and another doesn't. Some aspects of a man's lifestyle may affect his chances of developing prostate cancer. For example, some evidence suggests a link between diet and this disease. These studies show that prostate cancer is more common in populations that consume a high-fat diet (particularly animal fat), and in populations that have diets lacking certain nutrients. Although it is not known whether a diet low in fat will prevent prostate cancer, a low-fat diet may have many other health benefits.

There are large differences in prostate cancer risk between racial groups, but it is not yet clear why this is so. African Americans have the highest incidence of prostate cancer in the world.

Researchers are interested in genes that may influence the risk of developing prostate cancer. They are studying the genes of men who were diagnosed with prostate cancer at a relatively young age (less than 55 years old) and the genes of families who have several members with the disease. However, there are, as yet, few identified genes that are known to affect prostate cancer risk.

Prevention

Several studies are under way to explore how prostate cancer might be prevented. These include the use of dietary supplements, such as vitamin E and selenium. In addition, recent studies suggest that a diet that regularly includes tomato-based foods may help protect men from prostate cancer.

The drug finasteride was studied in the Prostate Cancer Prevention Trial. This drug is used to treat hair loss (marketed as Propecia). It functions by blocking the conversion of testosterone to dihydrotestosterone. Thousands of men from the United States participated in the study for a period of 7 years. The results of the study are a key finding in prostate cancer research, especially because of its findings about the prevalence of prostate cancer among men with supposedly 'normal' PSA results.

Scientists are also looking at ways to prevent recurrence among men who have been treated for prostate cancer. These approaches involve the use of drugs such as finasteride, flutamide, and LHRH agonists. Studies have shown that hormonal therapy after radiation therapy or after radical prostatectomy can benefit certain men whose cancer has spread to nearby tissues.

Researchers also are investigating whether diets that are low in fat and high in soy, fruits, s and other food products might prevent a recurrence. For example, the Adventist Health Study found that meat-eaters had a 54% increased risk for prostate cancer when compared with vegetarians, even after adjusting for age, sex, and smoking. Administrator note

In July, 2003, an Australian research team lead Graham Giles of The Cancer Council released a report of a medical study that concluded that frequent masturbation by males may be an effective preventative measure. It was speculated by the researchers that the resulting ejaculations helps remove carcinogens from the gland area. A subsequent study from the Health Professionals Study found no link between the two. Administrator note

Due to old and limited studies, it was thought that increased levels of sexual activity led to an increased risk of prostate cancer. The results of a much larger study published in JAMA seem to suggest the opposite, however. Culminating in 2004, the study found that men who ejaculated (through sexual activity or masturbation) 21 times or more a month had decreased levels of occurrence. This was true across all age groups.

Screening/Early detection

Researchers are studying ways to screen men for prostate cancer. At this time, it is not known whether screening for prostate cancer actually saves lives, even if the disease is found at an earlier stage.

Treatment

Many studies of new approaches for men with prostate cancer take the form of clinical trials.

Cryosurgery is under study as an alternative to surgery and radiation therapy. The doctor tries to avoid damaging healthy tissue by placing an instrument known as a cryoprobe in direct contact with the tumor to freeze it. The extreme cold destroys the cancer cells.

Doctors are studying new ways of using radiation therapy and hormonal therapy. They also are testing the effectiveness of chemotherapy and biological therapy for men whose cancer does not respond or stops responding to hormonal therapy. In addition, scientists are exploring new treatment schedules and new ways of combining various types of treatment. For example, they are studying the usefulness of hormonal therapy before primary therapy (surgery or radiation) to shrink the tumor.

For men with early stage prostate cancer, researchers also are comparing treatment with watchful waiting. The results of this work will help doctors know whether to treat early stage prostate cancer immediately or only later on, if symptoms occur or worsen.

References

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External links

• Prostate Cancer Foundation
• Information about prostate cancer on prostate.com
• IGF1R gene may increase prostate cancer treatment
• National Institute on Aging Information Center
• National Kidney and Urologic Diseases Information Clearinghouse
• Prostate Cancer Survivor One survivor's story
• Many NCI publications may be viewed or ordered on the Internet at http://cancer.gov/publications

Patient support sources:

• news://alt.support.cancer.prostate is a newsgroup quite active with men currently dealing with the disease.
• nonprofit prostate cancer website updated weekly
• largest patient supported non-commercial website for all aspects of prostate cancer

The original text of this article was taken from the public domain document NIH Publication No. 00-1576, which can be found at http://www.cancer.gov/cancerinfo/wyntk/prostate

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