- Last Updated: Thursday, 23 January 2014 00:47
- Written by Varien Moos
The evaluation of cancer begins with a clinical history and physical examination. Both help the doctor assess the risk of cancer than a person and determine the necessary studies to detect it. In general, the search for cancer is part of routine medical exam and is primarily to detect cancers of the thyroid, testicular, mouth, ovarian, skin and lymph nodes.
The screening tests try to identify cancer before it causes symptoms. If a test is positive, then further tests are needed to confirm the diagnosis. A cancer diagnosis must be made with absolute certainty, which usually requires a biopsy. It is also essential to determine the specific type of cancer. When cancer is detected, other tests to determine the stage of it help to know their exact location and whether it has spread to other organs. This helps doctors plan appropriate treatment and determine prognosis.
Early detection of cancer
The evidence of cancer screening used to detect the possible presence of cancer. Can help reduce the number of deaths from this cause. When cancer is detected in its early stages can usually be treated before it spreads. The screening tests are usually not definitive, the results are verified or refuted by further examinations and tests.
Although screening tests can help save lives, can also be very expensive and sometimes have an impact of a physical or psychological. Generally, screening tests produce a relatively high number of false positive results (results that suggest that a cancer is present when in fact it is not). They may also produce false negatives (results showing no signs of cancer that is truly present).
False positives can create psychological stress and can lead to the completion of other tests, expensive and risky. False negative results can reassure people, but it is a false security. For these reasons, doctors think carefully before deciding whether to perform or not such evidence.
Two screening tests widely used in women is the Pap test (Pap), which detects cervical cancer and mammography to detect breast cancer. Both have been successful in reducing rates of death from these cancers.
The determination of the amount of prostate specific antigen in the blood is a common screening test for men. The amounts of this antigen are higher in individuals with prostate cancer, but its presence is also high in those with an enlarged prostate benign cause. It remains unresolved whether the prostate specific antigen may or may not be used for the detection of prostate cancer.
The disadvantages of its use as a screening test are its high cost and possible false positive results.
Another common screening test is the search for hidden blood in the stool. The occult blood can not be visually observed, the stool sample should be analyzed. The discovery of blood in the stool is an indication that something is wrong in the colon.
The problem may be cancer, although many other disorders can also be lost small amounts of blood in the stool.
Some screening tests can be performed at home. For example, in women, monthly breast self-examination is extremely valuable to help detect breast cancer. Periodic review of the testicles can help men detect testicular cancer, one of the most curable forms of cancer when diagnosed early.
Periodic inspections of the mouth in search of sores may help detect oral cancer at an early stage.
Since there are several different types of cancer and its treatments vary, diagnose its presence and determine the specific variety to which they belong is essential. This requires nearly always obtain a sample of the suspected tumor and examined under microscope. It may be necessary to have several special tests on the sample to further characterize cancer. Knowing the type of cancer helps the doctor determine the studies to be performed, since each cancer tends to follow its own pattern of growth and extension.
More than 7 percent of patients with cancer, the studies identify metastases even before that distinguishes the original cancer. Sometimes the original cancer may not be discovered. Usually, however, can identify the type of the primary tumor with a biopsy of metastases and examining the tissue under a microscope.
However, the identification is not always easy or safe. The search intensity of the primary tumor is determined by the diagnosis made on the fabric. In general, doctors search if the primary tumor to treat can significantly influence the survival (eg breast cancer). If you identify the primary tumor does not change the treatment program or survival, no further testing makes sense.
Determination of the stages of cancer
When the cancer, the evidence to determine the stage of the same help doctors plan appropriate treatment and determine prognosis. Numerous tests were conducted to determine the location of the tumor, its size, its growth into nearby structures and spread to other parts of the body. Set the stage is fundamental to determine if healing is possible. Cancer patients sometimes are impatient and anxious during these tests, wanting immediate treatment of the tumor. However, these tests allow physicians to determine a smart attack therapy and planned.
The stage of the cancer study may include scans such as liver and bone, contrast studies, computed tomography (CT) or magnetic resonance imaging (MRI) to determine if cancer has spread. Mediastinoscopy, in which the inside of the chest (the mediastinum) is examined with a fiberoptic instrument, is used to determine if cancer, generally lung cancer has spread to lymph nodes. A bone marrow biopsy in which tissue is removed from the center of a bone and examined under a microscope, can help determine if cancer has spread there.
Sometimes surgery may be necessary to determine the stage of cancer. For example, a laparotomy (abdominal surgery) allows the surgeon to remove or treat colon cancer as it determines if it has spread to nearby lymph nodes, from which could continue until the water re-gado. An analysis of lymph nodes removed from the armpit during a mastectomy helps determine how far it has spread breast cancer, and if therapy is needed after surgery. An operation to remove the spleen (splenectomy) helps to determine the stages of Hodgkin's disease.
The ultrasound examination (sonography) is a painless and harmless procedure that uses sound waves to show the structure of internal organs. It is useful to identify and determine the size of certain cancers, particularly kidneys, liver, pelvis and prostate. Doctors also use ultrasound to guide the extraction of tissue samples during a needle biopsy.
Computed tomography (CT) is used to detect cancer in the brain, lungs and abdominal organs such as adrenal glands, lymph nodes, liver and spleen.
Lymphography is a test in which dye injected into the feet and is followed with X-rays as it rises. Help to identify abnormalities in the abdominal lymph nodes, but since the advent of CT, has almost been done.
Obtaining magnetic resonance imaging (MRI) is an alternative to CT. With this procedure, a very strong magnetic field generates richly detailed anatomical images. Is particularly useful for detecting cancers of the brain, bone and bone marrow. Do not use X-rays and is a very safe procedure.
What is pathology?
The most efficient procedure for the diagnosis of a tumor is inspection by microscope of a small sample (biopsy) extracted from it. To achieve this you need through a series of steps including sample collection, treatment to prepare it for microscopic examination and examination by an expert who makes the diagnosis based on the principle that each tumor has a microscopic appearance that is proper.
For most people the term "cancer" is synonymous with tumor, and both words are associated with a disease that results in a formidable personal, family or a loved one. However, the medical meaning of the word "tumor" does not correspond with this view. Since it was coined by the ancient Romans (see box "Tumors") only refers to abnormal enlargement of a portion of a body that appears as one or more packages. These may be apparent to the naked eye or detectable by palpation, when the tumor is located deep, just visible through more complex imaging study (radiography, tomography, ultrasound, etc.). Advances in medical knowledge have led to the recognition that many different causes give rise to tumors. These include inflammation, as they are generated abscesses, the collection of blood outside the blood vessels, bruising, congenital malformations, and an increase in the frequency with which certain cells reproduce, not linked to any of the reasons mentioned above. The latter condition is defined by the term neoplasia, word from neo: new, aggregate, and hyperplasia: proliferation, referring to a process whose result (the tumor) is added to normal structures.
The tumors were categorized into two groups: the benign and malignant lesions. The differences between them lie in their different biological behavior. In benign cells divide slowly, are similar to normal tissues maintain their orderly arrangement and the tumor is always restricted to the area where the growth started showing a net limit the surrounding tissues. By contrast in malignancies rapidly dividing cells and are only vaguely mimicking poorly differentiated cells from normal tissues. In this case the cells infiltrate and invade surrounding tissues and are capable of giving rise to metastases, ie, form tumors in other parts of the organism to spread through blood or lymph. With few exceptions, in malignancies tumor cells end up destroying the organism in which they develop. Malignant neoplasms are the group of diseases that are grouped under the name of cancer.