What is biopsy?
A biopsy is a small sample of tissue taken for microscopic examination so that the nature of a disease process can be accurately determined. The word ‘biopsy’ literally means ‘taking a look at life’. The term biopsy is also applied in common medical language to the specimen itself.
Biopsy is a valuable and accurate way of finding out exactly what is wrong with a person and, by establishing an important diagnosis at an early stage, it is often life-saving. Biopsies, especially from the skin, may often be taken after a simple injection of local anaesthetic, the skin opening then being closed with one or two stitches.
Why it should be done
Biopsies can save life. A person might have a coloured skin spot that has started to grow and change shape. An early biopsy might show that this was a malignant melanoma (skin cancer) at a stage at which it is still confined to the level near the skin surface. Careful and thorough removal at this stage could completely cure the condition. Failure to perform a biopsy might allow the tumor to spread widely.
Biopsy may be the only way to reach a definite diagnosis. If a lump is felt in a breast, for instance, only a biopsy can show for certain whether the lump is cancerous or benign. In an established case, biopsy can provide material from which the severity of the disease can often be determined.
How the biopsy is performed
Many biopsies are obtained simply by cutting out a suspicious-looking piece of tissue. In the course of surgery under general anesthesia, it is extremely common for biopsies to be taken. But there are other ways. The ‘Pap’ smear test, or cervical smear, for cancer of the neck of the womb (the cervix) is a biopsy.
Biopsy for a breast cancer
The diagnosis of breast cancer by microscopic examination, performed by a pathologist, requires a sample taken from the lump.
This may be obtained by cutting into the breast and removing suspect tissue under direct view, but it can also be done by taking out some cells through a needle inserted from the outside. This is called a needle biopsy and it is very frequently done.
Biopsy for a bowel cancer
In some bowel disorders where food is not being properly absorbed, a biopsy of the intestine lining is done. First, a special spring-loaded capsule on a string is swallowed. This is called a Crosby capsule. When in place, it can be triggered and will shut sharply, cutting off a piece of bowel lining. The capsule can then be pulled up and the specimen retrieved.
This type of biopsy is used in diagnostics of bowel cancer.
A biopsy of a bone
A bone-marrow biopsy is a valuable way of obtaining information about the state of the blood-forming tissues. The sample of marrow is usually taken from the crest of the pelvis at the back, and requires a small injection of local anesthetic.
A broad needle attached to a syringe is passed through the outer table of the bone into the marrow and about half a milliliter sucked out.
The biopsy enables an accurate diagnosis to be made of the various forms of anemia, including complete failure of red cell production (aplastic anemia), and of reduced white cell production (agranulocytosis) and the various kinds of white cell cancer (leukemia).
If the piece of tissue obtained by a biopsy method is large enough, it is usually placed on glass slides. An expert on the appearances of tissue disease (a histopathologist) then examines the slide under a powerful microscope and reports on the findings and diagnosis.
In cases of critical urgency, a report may be obtained within half an hour by freezing the tissue and cutting thin slices from the frozen block for immediate examination. This is known as a frozen section. It is sometimes done while the patient remains anesthetized on the operating table. What the surgeon does then will depend on what the pathologist finds.
Recovery after the biopsy
In most cases, the taking of a biopsy causes little or no distress or danger to the patient and recovery is unaffected.