Cancer masturbation testicular

Definition

Tumor markers are substances, such as proteins, biochemicals, or enzymes, produced by tumor cells or by the body in response to tumor cells. As tumor cells multiply, cancer spreads, and tissue is damaged, these substances increase and leak into the bloodstream. Tumor marker levels in blood help evaluate people for certain types of cancer.

Purpose

Tumor marker levels provide evidence about the likelihood of undiagnosed cancer or the status of treated cancer without the expense and discomfort of ultrasound, x-ray, or biopsy procedures. Tumor marker levels are used to screen for and diagnose cancer, predict a person's prognosis, monitor treatment, and watch for cancer recurrence.

Description

Tumor markers associated with common cancers include: AFP, Beta-HCG, CA 15-3, CA 19-9, CA 27.29, CA 125, CEA, and PSA. Some tumor markers are associated with many types of cancer; others, with as few as one. Some tumor markers are always elevated in specific cancers; others are less predictable.

A tumor marker test's ability to screen for and diagnose a specific type of cancer depends on its sensitivity and specificity. A test that is 100% sensitive has no false negatives. It is positive or increased in every person who has that type of cancer. A test that is 100% specific has no false positives. It is negative or decreased in every person who does not have that type of cancer.

Most tumor markers are neither sensitive nor specific enough to screen for or diagnose cancer without the support of other clinical findings. Increased levels are not found in all people with a specific type of cancer, yet may be found in some people without that type of cancer. In addition, tumor marker levels often do not increase until the person experiences symptoms.

Once cancer is diagnosed, tumor marker levels help determine the amount of cancer present. Higher levels usually indicate more advanced cancer and a worse prognosis. The person and his or her physician use this information to choose between more or less aggressive treatments.

Monitoring cancer treatment is the most common use of tumor markers. As cancer is reduced, levels decrease. Stable or increasing levels indicate the cancer is not responding to treatment.

The choice of tumor marker to use for monitoring is important. Only a marker elevated before treatment can be used to monitor a person during or after treatment. Timing of the tests is also important. Each tumor marker has a unique lifespan in the blood. To monitor a treatment's success, enough time must have passed for the initial marker to be cleared from the blood. Tests done too soon may be falsely elevated because the marker produced by the untreated cancer is still present.

Watching for cancer recurrence is another common reason for tumor marker testing. Periodic testing can detect a recurrence often months earlier than could an ultrasound, x-ray, or physical examination.

Tumor marker tests usually are done by combining a sample of blood with a substance containing antibodies to the tumor markers. These antibodies bind to the markers. Another substance is added, often a radioactive substance, to measure the amount of bound marker and antibodies. From this measurement, the amount of tumor marker is calculated.

Conclusions based on tumor marker tests are seldom based on one test result but on a series of test results, called serial measurements. A series of increasing or decreasing values is more significant than a single value.

Tumor marker testing is currently the object of much research. Their use is directed by approval from the Food and Drug Administration (FDA) and guidelines established by organizations such as the American Society of Clinical Oncology and the American Cancer Society.

Tumor marker test results are available within several days. Insurance coverage for markers still in the research stage for particular uses may vary with the company and individual policy.

Alpha-fetoprotein (AFP)

AFP is a protein normally made by only fetal tissue. When certain types of cells become cancerous, they revert to a fetal form and begin making AFP. Increased levels are associated most strongly with liver, testicular, and ovarian cancer. Seventy-percent of people with liver cancer have increased AFP levels. Levels indicate the extent of cancer. Serial measurements monitor treatment response.

Pregnant women and people with noncancerous liver conditions such as cirrhosis and hepatitis have moderately increased levels.

Beta-subunit human chorionic gonadotropin (Beta-HCG)

The beta-subunit of the hormone HCG is a marker for testicular cancer and cancers that begin in placental cells called trophoblasts. Women with choriocarcinoma (a cancer originating in the placenta following pregnancy) or molar pregnancy (a tumor inside the uterus) have increased levels of Beta-HCG, as do 70% of men with testicular cancer. Serial measurements monitor the progress and treatment of these cancers.

Cancer antigen 15-3 (CA 15-3)

CA 15-3 is produced by cells in the breast. Increased levels are associated with breast cancer. Rarely increased in women with early breast cancer, it is used to detect recurrence of cancer in women following treatment or mastectomy.

Cancer antigen 19-9 (CA 19-9)

CA 19-9 helps diagnose pancreatic cancer when combined with other test results and clinical findings. After diagnosis, levels help predict the success of surgery and to monitor the course of the cancer.

Not all people with pancreatic cancer have increased CA 19-9 levels. This marker is associated with a specific blood type. People with pancreatic cancer who are negative for this blood type will not have CA 19-9 in their blood. It is also increased in liver and gastrointestinal cancer and in noncancerous diseases, such as pancreatitis and jaundice.

Breast carcinoma-associated antigen (CA 27.29)