What Is Cancer?

Cancer is a group of many different diseases that have some important things in common. They all affect cells, the body's basic unit of life. To understand cancer, it is helpful to know about normal cells and what happens when cells become cancerous.

The body is made up of many types of cells. Normally, cells grow and divide to produce more cells only when the body needs them. This orderly process helps keep the body healthy.

If the cells keep dividing when new cells are not needed, they form too much tissue. Excess tissue can form a mass, called a tumor. Excess tissue can be benign or malignant.

• Benign tissue is not cancer. The cells do not invade nearby tissue or spread to other parts of the body.
  
• Malignant tissue is cancer. The cancer cells divide out of control. They can invade and destroy nearby healthy tissue. Also, cancer cells can break away from the tumor they form and enter the bloodstream and lymphatic system, This is how cancer spreads from the original (primary) tumor to form new tumors in other parts of the body. The spread of cancer is called metastasis.

Benign prostatic hyperplasia (BPH) is the abnormal growth of benign prostate cells. In BPH, the prostate grows larger and pushes against the urethra and bladder, blocking 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. Although this condition is seldom a threat to life, it may require treatment to relieve symptoms.

Most cancers are named for the type of cell or organ in which they begin. Cancer that begins in the prostate is called primary prostate cancer (or prostatic cancer). Prostate cancer may remain in the prostate gland, or it may spread to nearby lymph nodes. Prostate cancer may also spread to the bones, bladder, rectum, and other organs.

When cancer spreads to other parts of the body, the new tumor has the same malignant 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.

Symptoms

Early prostate cancer often does not cause symptoms. When symptoms of prostate cancer do occur, they may include some of the following problems:

• A need to urinate frequently, especially at night;
• Difficulty starting urination or holding back urine;
• Inability to urinate;
• Weak or interrupted flow of urine;
• Painful or burning urination;
• Painful ejaculation;
• Blood in urine or semen; and/or
• Frequent pain or stiffness in the lower back, hips, or upper thighs.

Any of these symptoms may be caused by cancer or by other, less serious health problems, such as BPH or an infection. Only a doctor can tell the cause. A man who has symptoms like these should see his family doctor or a urologist (a doctor who specializes in treating diseases of the genitourinary system). Do not wait to feel pain; early prostate cancer does not cause pain.

Diagnosis

If symptoms occur, the doctor asks about the patient's medical history, performs a physical exam, and may order laboratory tests. The exams and tests may include the following:

• Digital rectal exam--the doctor inserts a gloved, lubricated finger into the rectum and feels the prostate through the rectal wall to check for hard or lumpy areas.

• Blood tests--a lab measures the levels of prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) in the blood. The level of PSA in the blood may rise in men who have prostate cancer, BPH, or an infection in the prostate. The level of PAP rises above normal in many prostate cancer patients, especially if the cancer has spread beyond the prostate. The doctor cannot diagnose prostate cancer with these tests alone because elevated PSA or PAP levels may also indicate other, noncancerous problems. However, the doctor will take the results of these tests into account in deciding whether to check the patient further for signs of cancer.
  
• Urine test--a lab checks the urine for blood or infection.

The doctor may order other tests to learn more about the cause of the symptoms and to help determine whether conditions of the prostate are benign or malignant, such as:

• 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 patient will need to have a biopsy. A biopsy is the only sure way to know whether a problem is cancer. During a biopsy, the doctor removes a small amount of prostate tissue, 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 closely the tumor resembles normal prostate tissue and suggests how fast the tumor is likely to grow. One way of grading prostate cancer, called the Gleason system, uses scores of 2 to 10. Another system uses G1 through G4. Tumors with lower scores are less likely to grow or spread than tumors with higher scores.

A man who needs a biopsy may want to ask the doctor some of the following questions:

• How long will the procedure take? Will I be awake? Will it hurt?
• How soon will I know the results?
• If I do have cancer, who will talk to me about treatment? When?

If the physical exam and test results do not suggest cancer, the doctor may recommend medicine to reduce the symptoms caused by an enlarged prostate. Surgery is another way to relieve these symptoms. The surgery used in such cases is transurethral resection of the prostate (TURP or TUR). In TURP, an instrument is inserted through the penis to remove prostate tissue that is pressing against the upper part of the urethra.