Testing Biopsy and Cytology Specimens for Cancer

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Overview of cytology types

Diagnosing diseases by looking at single cells and small clusters of cells is called cytology or cytopathology. It has become an important part of cancer diagnosis over the past few decades.

Compared with tissue biopsy, a cytology specimen usually:

  • Is easier to get
  • Causes less discomfort to the patient
  • Is less likely to result in serious complications
  • Costs less

The disadvantage is that, in some cases, a tissue biopsy result is more accurate, though in many cases the cytology fluid may be just as accurate.

Sometimes an excisional biopsy (removing the entire tumor) is the only treatment needed to remove a cancer. In other cases, a cancer might be better treated by chemotherapy or radiation therapy, and surgery might be done after these treatments. For those types of cancer, a cytology sample, endoscopic biopsy, core needle biopsy, or incisional biopsy might be a better choice. As you can see, choices of tests are not simple – the doctors consider many factors about the specific type of cancer that’s suspected and what organ is affected.

Cytology tests may be used in 2 ways – for diagnosis or for screening.

A diagnostic test is only used for people who have signs, symptoms, or some other reason to suspect that a particular disease (like cancer) may be present. A diagnostic test finds out if a disease is present and, if so, it precisely and accurately classifies the disease.

A screening test is used to find people who might have a certain disease even before they develop symptoms. A screening test is expected to find nearly all people who are likely to have the disease, but a screening test does not always prove that the disease is present. Often, a diagnostic test is used if a screening test is positive (that is, if something is found on the screening test). Some cytology tests, such as the Pap test are mainly used for screening while others can accurately identify cancers (see “Scrape or brush cytology” below). When cytology shows cancer, often a biopsy is also done to be sure of any abnormal finding before treatment is started.

Fine needle aspiration biopsy

Fine needle aspiration (FNA) is sometimes considered a cytology test and is sometimes considered a biopsy. It’s discussed in the section called “Overview of biopsy types.”

Body fluids

Fluids from cavities and spaces in the body can be tested to see if cancer cells are present. Some of the body cavity fluids tested in this way include:

  • Urine
  • Sputum (phlegm)
  • Spinal fluid, also known as cerebrospinal fluid or CSF (from the space surrounding the brain and spinal cord)
  • Pleural fluid (from the space around the lungs)
  • Pericardial fluid (from the sac that surrounds the heart)
  • Ascitic fluid, also called ascites or peritoneal fluid (from the space in the belly)

Scrape or brush cytology

Another cytology technique is to gently scrape or brush some cells from the organ or tissue being tested. The best-known cytology test that samples cells in this way is the Pap test. Pap test samples are taken by using a small spatula and/or brush to remove cells from the cervix (the lower part of the uterus or womb). Other areas that can be brushed or scraped include the esophagus (swallowing tube), stomach, bronchi (breathing tubes that lead to the lungs), and mouth.


Last Medical Review: 01/29/2013
Last Revised: 03/07/2013