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. 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.

Signs and symptoms of prostate cancer

Having the following signs and symptoms does not necessarily mean you have prostate cancer. They could be caused by other prostate problems, so see your doctor to be sure.

Prostate cancer is generally slow growing and may not cause any symptoms for years. Its signs and symptoms are usually divided into 2 groups:

Localized (involving the prostate gland)

• decrease in the size and force of your urinary stream (weak, interrupted flow)
• difficulty starting (hesitancy) or stopping urine flow (dribbling)
• urgent need to urinate
• frequent urination during the day and especially at night (nocturia)
• inability to urinate
• blood in your urine (hematuria)
• pain during ejaculation
  

Generalized (involving areas where the cancer has spread)

• bone pain is the most frequent symptom of cancer that has spread
• aching pain in the lower back, hips, thighs or groin
• weight loss
• constant tiredness
• urinary obstruction and/or retention
• low red blood cell count (anemia)