Testing Biopsy and Cytology Specimens for Cancer

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Overview of biopsy types

Tissue or cell samples can be taken from almost any part of the body. How samples are taken depends on where the tumor is and what type of cancer is suspected. For instance, the methods used for skin biopsies are very different from those done for brain biopsies.

Some types of biopsies remove an entire organ. These types are done only by surgeons. Other types of biopsies may remove tumor samples through a thin needle or through an endoscope (a flexible lighted tube). These biopsies are often done by surgeons, but can also be done by other doctors.

The most common biopsy types used in cancer diagnosis are discussed in this section. For more complete information, refer to the diagnosis section of our detailed guides on specific types of cancer.

Needle biopsy

There are 2 types of needle biopsies:

  • Fine needle biopsy (also called fine needle aspiration)
  • Core needle biopsy (also called core biopsy)

Fine needle aspiration

Fine needle aspiration (FNA) uses a very thin needle and a syringe to take out a small amount of fluid and very small pieces of tissue from the tumor. The doctor can aim the needle while feeling a suspicious tumor or area near the surface of the body. If the tumor is deep inside the body and cannot be felt, the needle can be guided while being watched on an imaging test such as an ultrasound or CT scan.

The main advantages of FNA are that it does not require an incision (cutting through the skin), and in some cases it’s possible to make a diagnosis the same day. The disadvantage is that sometimes this needle cannot remove enough tissue for a definite diagnosis. Although FNA is a type of biopsy, it’s also classified as a cytology test (see the next section).

Core biopsy

Core biopsy uses needles that are slightly larger than those used in FNA. They remove a small cylinder of tissue (about 1/16 inch in diameter and 1/2 inch long). The core needle biopsy is done using local anesthesia (drugs used to make the area numb) in the doctor’s office or clinic. Like FNA, a core biopsy can sample tumors that the doctor can feel as well as smaller ones that must be seen using imaging studies.

Doctors sometimes use special vacuum tools to get larger core biopsies from breast tissue. (For more information, see our document, For Women Facing a Breast Biopsy.)

Processing core biopsy samples usually takes longer than processing FNA biopsies.

Excisional or incisional biopsy

In this type of biopsy, a surgeon cuts through the skin to remove the entire tumor (called an excisional biopsy) or a small part of a large tumor (called an incisional biopsy). This is often done using local anesthesia or regional anesthesia (drugs used to numb the area). If the tumor is inside the chest or abdomen (belly), general anesthesia is used (to put the patient into a deep sleep so they will feel no pain).

Endoscopic biopsy

An endoscope is a thin, flexible, lighted tube that has a lens or a video camera on the end. It can let a doctor look inside different parts of the body. Tissue samples can also be taken out through the endoscope to find out if cancer is present and, if so, the type.

Different endoscopes are used to look at different parts of the body. For example, one type of endoscope is used to look at the inside of the nose, sinuses, and throat. Another type of endoscope is used to look at the upper part of the digestive tract: the esophagus (the tube that connects the throat to the stomach), the stomach, and the first part of the intestine.

Some endoscopes are named for the part they are used to look at. For instance, a cystoscope is used to look at the urethra (urine tube) and bladder, a hysteroscope to look at the uterus (womb), a bronchoscope to look at the lungs and bronchi (breathing tubes), and a colonoscope to look at the colon (large intestine).

Laparoscopic, thoracoscopic, and mediastinoscopic biopsy

Laparoscopy is much like endoscopy but uses a slightly different scope (a laparoscope) to look inside the abdomen (belly) and remove tissue samples. A small incision (cut) is made in the abdomen then the laparoscope is passed through this opening to see inside. Procedures like this that look inside the chest are called thoracoscopy and mediastinoscopy.

Laparotomy and thoracotomy

A laparotomy is a type of surgery that cuts into the abdomen. It’s usually a vertical cut from upper to lower abdomen. This may be done when a suspicious area cannot be diagnosed using less invasive tests (like a needle biopsy or laparoscopy). During the laparotomy, a biopsy sample can be taken from a suspicious area. The doctor can also look at the size of the area and its location. Nearby tissues can be checked, too. General anesthesia is used for this procedure. A similar operation which opens the chest is called thoracotomy.

Skin biopsies

There are many ways to take a biopsy of the skin. Doctors choose the one best suited to the type of skin tumor suspected. Shave biopsies remove the outer layers of skin and are fine for some basal cell or squamous cell skin cancers, but they are not recommended for suspected melanomas of the skin. Punch biopsies or excisional biopsies (as discussed above) remove deeper layers of the skin, and can find out how deeply a melanoma has gone into the skin – an important factor in choosing treatment for that type of cancer.

Sentinel lymph node mapping and biopsy

Lymph node mapping helps the surgeon know which lymph nodes to remove for an excisional biopsy. Sentinel node mapping and biopsy has become a common way to find out whether the cancer (especially melanoma and breast cancer) has spread to the lymph nodes. This procedure can find the lymph nodes that drain lymph fluid from the area where the cancer started. If the cancer has spread, these lymph nodes are usually the first place it will go. This is why these lymph nodes are called sentinel nodes (meaning that they stand watch over the tumor area, so to speak).

To find the sentinel lymph node (or nodes), the doctor injects a small amount of slightly radioactive material into the area of the cancer. By checking various lymph node areas with a machine that detects radioactivity (like a Geiger counter), the doctor can find the group of lymph nodes the cancer is most likely to travel to. Then the doctor injects a small amount of a harmless blue dye into the site of the cancer. After about an hour, a surgeon makes a small incision in the lymph node area that was found with the radioactive test. Those lymph nodes are then checked to find which one(s) turned blue or became radioactive. (Sometimes the dye and the radioactive material may be mixed together, or either part may be used alone.)

When the sentinel node has been found, it’s removed (an excisional biopsy) and looked at under a microscope. If the sentinel node does not contain cancer cells, no more lymph node surgery is needed because it’s very unlikely the cancer would have spread beyond this point. If cancer cells are found in the sentinel node, the rest of the lymph nodes in this area are removed and looked at, too. This is called a lymph node dissection.

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