Prostate cancer chemotherapy

Definition

Prostate cancer is a disease is which the cells of the prostate become abnormal and start to grow uncontrollably, forming tumors. Tumors that can spread to other parts of the body are called malignant tumors or cancers. Tumors that are not capable of spread are said to be benign.

Description

Prostate cancer is the most common cancer among men in the United States, and is the second leading cause of cancer deaths. The American Cancer Society estimates that in 1998, at least 185,000 new cases of prostate cancer will be diagnosed, and it will cause at least 40,000 deaths. Although prostate cancer may be very slow-growing, it is a heterogeneous disease and can be quite aggressive, especially in younger men. When the disease is slow-growing it often may go undetected. Because it may take many years for the cancer to develop, many men with the disease will probably die of other causes rather than from the cancer.

Prostate cancer affects black men twice as often as it does white men, and the mortality rate among African-Americans is also two times higher. African-Americans have the highest rate of prostate cancer in the world.

The prostate, testicles, and seminal vesicles are the major male sex glands. These three glands together secrete the fluid that makes up semen. The prostate is about the size of a walnut and lies just behind the urinary bladder. A tumor in the prostate interferes with proper control of the bladder and normal sexual functioning. Often, the first symptom of prostate cancer to develop is difficulty in urinating. However, because the same symptom can be caused by a very common, non-cancerous condition of the prostate (benign prostatic hyperplasia), it does not always mean that prostate cancer is present.

As the prostate cancer grows, some of the cells break off and spread to other parts of the body through the lymph or the blood. The most common sites to which it spreads are the lymph nodes, the lungs, and various bones around the hips and the pelvic region.

Causes & symptoms

The cause of prostate cancer is not known, however, it is found mainly in men over the age of 55. The average age at diagnosis is 72. In fact, 80% of the prostate cancer cases occur in men over the age of 65. As men grow older, the likelihood of getting prostate cancer increases. While only 1 in 100,000 men will get prostate cancer under the age of 40, the frequency rises to 1,326 cases in 100,000, for men between the ages of 70-74. Hence, age appears to be a risk factor for prostate cancer. Race may be another contributing factor, because African-Americans have the highest rate of prostate cancer in the world.

Some studies have shown that a family history of prostate cancer, puts a man at a higher risk for getting this disease. In addition, there is some evidence to suggest that a diet high in fat increases the risk of prostate cancer. Workers in the electroplating and welding industries who are exposed to the metal cadmium and rubber industry workers appear to have a higher than average risk of getting this disease. Research has indicated that men with high plasma testosterone levels also may be at an increased risk for developing prostate cancer.

Frequently, prostate cancer has no symptoms, and the disease is diagnosed when the patient goes for a routine screening examination. However, occasionally, when the tumor is big or the cancer has spread to the nearby tissues, the following symptoms may be seen:

• Weak or interrupted flow of the urine
• Frequent urination (especially at night)
• Difficulty starting urination
• Inability to urinate
• Pain or burning sensation when urinating
• Blood in the urine
• Persistent pain in lower back, hips, or thighs (bone pain)
• Painful ejaculation.

Diagnosis

Prostate cancer is curable when detected early. However, because the early stages of prostate cancer may not have any symptoms, it often goes undetected until the patient goes for a routine physical examination. Diagnosis of the disease is made using some or all of the following tests.

Digital rectal examination (DRE)

In order to perform this test, the doctor puts a gloved, lubricated finger (digit) into the rectum to feel for any lumps in the prostate. The rectum lies just behind the prostate gland, and a majority of prostate tumors begin in the posterior region of the prostate. If the doctor does detect an abnormality, he or she may order more tests in order to confirm these findings.

Blood tests are used to measure the amounts of certain protein markers, such as prostate-specific antigen (PSA), found circulating in the blood. The cells lining the prostate generally make this protein and a small amount can be detected in the bloodstream. However, prostate cancers produce a lot of this protein, and it can be easily detected in the blood. Hence, when PSA is found in the blood in higher than normal amounts (for the patient's age group), cancer may be present.

A small probe is placed in the rectum, and sound waves are released from the probe. These sound waves bounce off the prostate tissue and an image is created. Since normal prostate tissue and prostate tumors reflect the sound waves differently, the test can be used to detect tumors quite efficiently. Though the insertion of the probe into the rectum may be slightly uncomfortable, the procedure is generally painless and only takes 20 minutes.

If cancer is suspected from the results ofany of the above tests, the doctor will remove a small piece of prostate tissue with a hollow needle. This sample is then checked under the microscope for the presence of cancerous cells. Prostate biopsy is the most definitive diagnostic tool for prostate cancer.

If cancer is detected during the microscopic examination of the prostate tissue, the pathologist will "grade" the tumor. This means that he will score the tumor on a scale of 1 to 10 to indicate how aggressive the tumor is. Tumors with a lower score are less likely to grow and spread than are tumors with higher scores. This method of grading tumors is called the Gleason system. This is different from "staging" of the cancer. When a doctor stages a cancer, he gives it a number that indicates whether it has spread and the extent of spread of the disease. In Stage I, the cancer is localized in the prostate in one area, while in the last stage, Stage IV, the cancer cells have spread to other parts of the body.