What Is Prostate Cancer

What Is Prostate Cancer 2

What Is Prostate Cancer 4

What Is Prostate Cancer 5

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    What Is It?

What Is Cancer?

What Is Prostate Cancer?

What Are the Key Statistics About Prostate Cancer?

Causes, Risk Factors and Prevention

What Are The Risk Factors for Prostate Cancer?

Do We Know What Causes Prostate Cancer?

Can Prostate Cancer Be Prevented?

Early Detection, Diagnosis, Staging

Can Prostate Cancer Be Found Early?

How Is Prostate Cancer Diagnosed?

How Is Prostate Cancer Staged?

Treating Prostate Cancer

How Is Prostate Cancer Treated?

Expectant Management (Watchful Waiting)

Surgery

Radiation Therapy

Cryosurgery

Hormone (Androgen Deprivation) Therapy

Chemotherapy

Treatment of Pain and Other Symptoms

Clinical Trials

Complementary and Alternative Therapies

Considering Prostate Cancer Treatment Options

Treatment Options by Stage

More Treatment Information

Talking With Your Doctor

What Should You Ask Your Doctor About Prostate Cancer?

What Will Happen After Treatment for Prostate Cancer?

More Information
What's New in Prostate Cancer Research and Treatment?Additional ResourcesReferencesExpert Answers

What Is Cancer?

Cancer develops when cells in a part of the body begin to grow out of control. Although there are many kinds of cancer, they all start because of out-of-control growth of abnormal cells.

Normal body cells grow, divide, and die in an orderly fashion. During the early years of a person's life, normal cells divide more rapidly until the person becomes an adult. After that, cells in most parts of the body divide only to replace worn-out or dying cells and to repair injuries.

Because cancer cells continue to grow and divide, they are different from normal cells. Instead of dying, they outlive normal cells and continue to form new abnormal cells.

Cancer cells develop because of damage to DNA. This substance is in every cell and directs all activities. Most of the time when DNA becomes damaged the body is able to repair it. In cancer cells, the damaged DNA is not repaired. People can inherit damaged DNA, which accounts for inherited cancers. More often, though, a person's DNA becomes damaged by exposure to something in the environment, like smoking.

Cancer usually forms as a tumor. Some cancers, like leukemia, do not form tumors. Instead, these cancer cells involve the blood and blood-forming organs and circulate through other tissues where they grow.

Often, cancer cells travel to other parts of the body where they begin to grow and replace normal tissue. This process is called metastasis. Regardless of where a cancer may spread, however, it is always named for the place it began. For instance, breast cancer that spreads to the liver is still called breast cancer, not liver cancer.

Not all tumors are cancerous. Benign (noncancerous) tumors do not spread (metastasize) to other parts of the body and, with very rare exceptions, are not life threatening.

Different types of cancer can behave very differently. For example, lung cancer and breast cancer are very different diseases. They grow at different rates and respond to different treatments. That is why people with cancer need treatment that is aimed at their particular kind of cancer.

Cancer is the second leading cause of death in the United States. Half of all men and one third of all women in the United States will develop cancer during their lifetimes. Today, millions of people are living with cancer or have had cancer. The risk of developing most types of cancer can be reduced by changes in a person's lifestyle, for example, by quitting smoking and eating a better diet. The sooner a cancer is found and treatment begins, the better are the chances for living for many years.

What Is Prostate Cancer?

About the Prostate

The prostate, found only in men, is a walnut-sized gland located in front of the rectum and underneath the urinary bladder. It contains gland cells that produce some of the seminal fluid, which protects and nourishes sperm cells in semen. Just behind the prostate gland are the seminal vesicles that produce most of the fluid for semen. The prostate surrounds the first part of the urethra, the tube that carries urine from the bladder and semen out of the body through the penis.

Male hormones stimulate the prostate gland to develop in the fetus. Male hormones are also called androgens. The most common androgen is testosterone. The prostate continues to grow as a man reaches adulthood and is maintained after it reaches normal size as long as male hormones are produced. If male hormone levels are low, the prostate gland will not fully develop. In older men, the part of the prostate around the urethra often continues to grow, a condition called benign prostatic hypertrophy or benign prostatic hyperplasia. This can cause problems with urinating because the overgrowth can narrow the urethral opening.

What Are the Key Statistics About Prostate Cancer?

Prostate cancer is the most common cancer, excluding skin cancers, in American men. The American Cancer Society (ACS) estimates that during 2006 about 234,460 new cases of prostate cancer will be diagnosed in the United States. About 1 man in 6 will be diagnosed with prostate cancer during his lifetime, but only 1 man in 34 in the US population will die of this disease. A little over 1.8 million men in the United States are survivors of prostate cancer.

Prostate cancer is a leading cause of cancer death in American men. The American Cancer Society estimates that 27,350 men in the United States will die of prostate cancer during 2006. Prostate cancer accounts for about 9% of cancer-related deaths in men.

Ninety-one percent of all prostate cancers are found in the local and regional stages (local means it is still confined to the prostate; regional means it has spread from the prostate to nearby areas, but not to distant sites such as bone). The 5-year relative survival rate for all of these men is nearly 100%.

The 5-year relative survival rate for men whose prostate cancers have already spread to distant parts of the body at the time of diagnosis is about 34%.

Five-year and 10-year survival rates refer to the percentage of men who live at least 5 or 10 years after their prostate cancer is first diagnosed. Relative survival rates assume that people will die of other causes and compare the observed survival with that expected for people without prostate cancer. That means that relative survival only talks about deaths from prostate cancer.

Because prostate cancer usually occurs in older men who often have other health problems, relative survival rates are generally used to produce a standard way of discussing prognosis (outlook for survival).

Unfortunately, it is impossible to have completely up-to-date survival figures. To realistically measure 10-year survival rates, we must have records of patients diagnosed at least 13 years ago. We need 10 years of follow-up plus the time it takes to assemble the data.

Modern methods of detection and treatment now mean that prostate cancers are detected earlier and treated more effectively, which has led to a yearly drop in death rate of about 3.5% in recent years. This means that if you are diagnosed this year, your outlook is probably better than the numbers above.

What Are The Risk Factors for Prostate Cancer?

A risk factor is anything that increases your chance of developing a disease such as cancer. Different cancers have different risk factors. For example, exposing skin to strong sunlight is a risk factor for skin cancer. Smoking is a risk factor for cancers of the lungs, mouth, throat, larynx, bladder, and several other organs. But having a risk factor, or even several, does not mean that you will get the disease.

Many people with one or more risk factors never develop cancer, while others with this disease may have no known risk factors. It is important, however, that you know about risk factors so that you can try to change any unhealthy lifestyle behaviors or can choose to have the early detection tests for a potential cancer.

Although we don’t yet completely understand the causes of prostate cancer, researchers have found several factors that increase the risk of developing this disease.

Age

The chance of having prostate cancer increases rapidly after age 50. About two thirds of all prostate cancers are diagnosed in men over the age of 65. It is still unclear why this increase with age occurs.

Race

Prostate cancer occurs about 60% more often in African-American men than in white American men. Compared with men of other races, African-American men are more likely to be diagnosed at an advanced stage. African-American men are more than twice as likely to die of prostate cancer as white men. Prostate cancer occurs less frequently in Asian men than in whites. Hispanic men develop prostate cancer at similar rates as white men. The reasons for these racial differences are not clear.

Nationality

Prostate cancer is most common in North America and northwestern Europe. It is less common in Asia, Africa, Central America, and South America. The reason for this is not well understood, but we know that is not simply due to better screening in North America and Europe. For example, Chinese men in Los Angeles have one-fifth the prostate cancer risk of white men in the US population.

Family History

Prostate cancer seems to run in some families, suggesting an inherited or genetic factor. Having a father or brother with prostate cancer more than doubles a man's risk of developing this disease. (The risk is higher for men with an affected brother than for those with an affected father.) The risk is much higher for men with several affected relatives, particularly if their relatives were young at the time of diagnosis.

Scientists have identified several inherited genes that seem to increase prostate cancer risk (see next section), but they probably account for only a small fraction of cases. Genetic testing for these genes is not yet available.

Some inherited genes increase risk for more than one type of cancer. For example, inherited mutations of the BRCA1 or BRCA2 genes are the reason that breast and ovarian cancers are much more common in some families. The presence of these gene mutations may also increase prostate cancer risk in some men, but they are responsible for a very small percentage of prostate cancer cases.

Diet

Men who eat a lot of red meat or who have a lot of high-fat dairy products in their diet appear to have a slightly higher chance of developing prostate cancer. These men also tend to eat fewer fruits and vegetables. Doctors are not sure which of these factors is responsible for increasing risk.

Some studies have suggested that men who consume a lot of calcium (through diets or supplements) may have a higher risk of developing advanced prostate cancer. Most studies, however, have not found such a link with the levels of calcium commonly consumed in the average diet, and it’s important to note that calcium is known to have other important health benefits.

Exercise

In most studies, exercise has not been shown to reduce prostate cancer risk. A recent study from the Harvard School of Public Health, however, found that men over age 65 who exercise vigorously have a lower rate of prostate cancer.

Vasectomy

Some earlier studies suggested that men who have had a vasectomy (surgery to make men infertile) may have a slightly increased risk for prostate cancer, but this link has not been consistently found. Among the studies that noticed an increase in risk, some found this risk to be highest in men who were younger than 35 when they had a vasectomy.

Research to resolve this issue is still in progress. However, most recent studies have not found any increased risk among men who have had this operation, and fear of an increased risk of developing prostate cancer should not be a reason to avoid a vasectomy.

Although several cell types are found in the prostate, over 99% of prostate cancers develop from the glandular cells. Glandular cells make the seminal fluid that is secreted by the prostate. The medical term for a cancer that starts in glandular cells is adenocarcinoma. Because other types of prostate cancer are so rare, if you have prostate cancer, it is almost certain to be an adenocarcinoma. The rest of this document refers only to prostate adenocarcinoma.

Most prostate cancers grow slowly. Autopsy studies show that many older men who died of other diseases also had prostate cancer that never affected them, and which neither they nor their doctor were aware of. Researchers studying the prostate glands of men who died have found prostate cancer in very few men in their 30s. But this number climbs with age so that by age 80, 70% to 90% of the men will have cancer in their prostate. Some prostate cancers, however, can grow and spread quickly.

Some doctors believe that prostate cancer begins with a condition called prostatic intraepithelial neoplasia (PIN). PIN begins to appear in men in their 20s. Almost 50% of men have PIN by the time they reach 50. In this condition there are changes in the microscopic appearance (size, shape, etc.) of prostate gland cells. These changes are classified as either low-grade, meaning they appear almost normal or high-grade, meaning they look abnormal.

If you have had high-grade PIN diagnosed on a prostate biopsy, there is a 30% to 50% chance that cancer is also present within your prostate. For this reason, men diagnosed with high-grade PIN are watched carefully and have repeat prostate biopsies.

Do We Know What Causes Prostate Cancer?

We still do not know exactly what causes prostate cancer. But researchers have found some risk factors and are trying to learn just how these factors cause prostate cells to become cancerous. (Please see the section "What Are the Risk Factors for Prostate Cancer?")

During the past few years, scientists have made great progress in understanding how certain changes in DNA can cause normal prostate cells to grow abnormally and form cancers. DNA is the chemical that carries the instructions for nearly everything our cells do. The reason that you might look like your parents is because they are the source of your DNA.

However, DNA affects more than the way you look. Some genes (parts of your DNA) contain instructions for controlling when cells grow and divide. Certain genes that promote cell growth and division are called oncogenes. Others that slow down cell division or cause cells to die at the right time are called tumor suppressor genes. Cancers can be caused by DNA mutations (defects) that turn on oncogenes or turn off tumor suppressor genes.

Some people are more likely to develop certain types of cancer because of DNA mutations they inherited from a parent. Researchers have discovered inherited DNA changes in certain genes that make some men more likely to get prostate cancer. These genetic changes may cause about 5% to 10% of prostate cancers.

Several genes that are mutated and may be responsible for a man's inherited tendency to develop prostate cancer have been described. The first of these is called HPC1 (abbreviated from Hereditary Prostate Cancer Gene 1). But there are many other genes described that are mutated and may be responsible for hereditary prostate cancer. None of these is a prominent cause of hereditary prostate cancer, and research on these genes is still preliminary. Genetic tests are not yet available.

As mentioned above, mutations of the BRCA1 or BRCA2 genes greatly increase a woman's risk of developing breast or ovarian cancer. Men with BRCA gene changes may have a slight to moderately increased prostate cancer risk. But BRCA changes are believed to account for only a very small number of prostate cancers.

Most DNA mutations related to prostate cancer develop during a man's life rather than having been inherited before birth. Every time a cell prepares to divide into two new cells, it must make a copy of its DNA. This process is not perfect, and sometimes errors occur. Fortunately, cells have repair enzymes that correct mistakes in the DNA. But some errors may slip past (especially if the cells are growing rapidly), leaving the flawed DNA in the new cell.

Exposure to radiation or cancer-causing chemicals may cause DNA mutations in many organs of the body, but these factors have not been proven to be important causes of mutations in prostate cells.

There is evidence that development of prostate cancer is linked to increased levels of certain hormones. High levels of androgens (male hormones, such as testosterone) may contribute to prostate cancer risk in some men.

Some researchers have noted that men with high levels of another hormone, insulin-like growth factor-1 (IGF-1), are more likely to develop prostate cancer. IGF-1 hormone is similar to insulin, but its normal function relates to cell growth, not sugar metabolism. Some studies, however, have not found any associations between IGF-1 and prostate cancer risk. Further research is needed to figure out the practical value of these observations.

Can Prostate Cancer Be Prevented?

Because the exact cause of prostate cancer is not known, at this time it is not possible to prevent most cases of the disease. Many risk factors such as age, race, and family history cannot be controlled. Current information on prostate cancer risk factors, however, suggests that some cases might be prevented

Current information on prostate cancer risk factors, however, suggests that some cases might be prevented.

Diet

You may be able to reduce your risk of prostate cancer by changing the way you eat.

The American Cancer Society recommends eating a variety of healthful foods, with an emphasis on plant sources, and limiting your intake of red meats, especially those high in fat or processed. Eat 5 or more servings of fruits and vegetables each day. Bread, cereals, grain products, rice, pasta, and beans are also recommended. These guidelines on nutrition may also lower the risk for some other types of cancer, as well as other health problems.

Tomatoes (raw, cooked, or in tomato products such as sauces or ketchup), pink grapefruit, and watermelon are rich in lycopenes. These vitamin-like substances are antioxidants that help prevent damage to DNA and may help lower prostate cancer risk.

Taking vitamin or mineral supplements may affect your prostate cancer risk, but this is not yet clear. Some studies suggest that taking 50 milligrams (or 400 International Units) of vitamin E daily can lower risk.

Other studies have concluded that vitamin E supplements have no impact on cancer risk and may increase risk for some kinds of heart diseases. Selenium, a mineral, may also lower risk. On the other hand, vitamin A supplements may actually increase prostate cancer risk. Taking supplements can have risks and benefits and before starting vitamins or other supplements, you should talk with your doctor.

The Selenium and Vitamin E Cancer Prevention Trial (SELECT) is a large clinical trial designed to determine if either (or both) of these 2 supplements can help protect against prostate cancer. The study opened in 2001 and has enrolled more than 32,000 men. The results of the study will probably not be available for several years.

Medicines

Some drugs may also help reduce the risk of prostate cancer.

Researchers have been interested in determining whether a drug called finasteride (Proscar), which is already used to treat benign prostatic hyperplasia (BPH), can reduce prostate cancer risk. Finasteride prevents the body from making a certain potent androgen (male hormone). Androgens are known to be important in promoting the growth of normal and cancerous prostate cells and may play a part in the development of prostate cancers.

The Prostate Cancer Prevention Trial (PCPT) was a study that enrolled more than 18,000 men to determine whether finasteride reduced the risk of developing prostate cancer. Each man in the study was randomly assigned to take either finasteride or a placebo pill each day for 7 years. The men didn’t know which pill they were taking.

At the end of the study, the men taking finasteride were about 25% less likely to have developed prostate cancer than those getting the placebo. But the cancers that developed in the men taking finasteride looked like they were more likely to grow and spread. The reason for this is not known. The study researchers are continuing to watch these men to see if these cancers truly are more aggressive.

The men taking finasteride were more likely to experience sexual side effects, such as decreased sexual desire and episodes of impotence, than those taking placebo. But they were less likely to have urinary problems, such as difficulty urinating and inability to hold urine in (incontinence).

At this time, it is unclear if taking finasteride to prevent prostate cancer is a good thing. The results of the PCPT will become clearer over the next few years.

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