Endoscopy (en-dahs-kuh-pee) is a medical procedure that uses tube-like instruments (called endoscopes) to look at the inside of the body. This procedure is different from imaging tests, such as x-rays, which also look at the inside of the body but usually do not place instruments inside the body.

There are many different kinds of endoscopes, or "scopes." Some are hollow, allowing the doctor to see directly into the body, while others use fiber optics (flexible glass or plastic fibers that transmit light). Still others have a small video camera on the end for viewing. Some endoscopes are stiff, while others are flexible. Endoscopes also vary in length. Each type is specially designed for looking at a different part of the body.

Depending on the area of the body being looked at, the endoscope may be inserted through an opening like the mouth, anus, or urethra (the tube that carries urine out of the bladder). In some cases, the endoscope is inserted through a small skin incision.

Some types of endoscopes and the areas of the body they are used to view are listed below:

Type of Endoscope	Inserted Into or Thru	Body Area(s) Examined	Name(s) of Procedures
bronchoscope	mouth or nose	trachea (windpipe) and bronchi (tubes inside the lungs)	bronchoscopy, flexible bronchoscopy
colonoscope	anus	colon (large intestine)	colonoscopy, lower endoscopy
cystoscope	urethra	urinary bladder	cystoscopy, cystourethroscopy
esophagogastroduodenoscope	mouth	esophagus (swallowing tube), stomach, and duodenum (first part of small intestine)	esophagogastroduodenoscopy (EGD), panendoscopy, upper endoscopy, gastroscopy
hysteroscope	vagina	inside of uterus	hysteroscopy
laparoscope	incision(s) in abdomen	space inside abdomen and pelvis	laparoscopy, peritoneal endoscopy
laryngoscope	mouth or nose	larynx (voice box)	laryngoscopy
mediastinoscope	incision above sternum (breastbone)	mediastinum (space between the lungs)	mediastinoscopy
sigmoidoscope (flexible sigmoidoscope)	anus	rectum and sigmoid colon (lower part of large intestine)	sigmoidoscopy, flexible sigmoidoscopy, proctosigmoidoscopy
thoracoscope	incision(s) in chest	space between lungs and chest wall	thoracoscopy, pleuroscopy

When Is Endoscopy Used?

Endoscopes were first developed to look at parts of the body that couldn't be seen any other way. This is still a common reason to use them, but endoscopy now has many other uses too. It can be useful in many medical conditions, but this section will focus on its role in the prevention, early detection, diagnosis, staging, and treatment of cancer.

Preventing and Screening for Cancer

Some types of endoscopes can be used to look for cancer in people who have no symptoms. For example, colonoscopy and sigmoidoscopy are procedures used to screen for colorectal cancer. These procedures can also help prevent cancer by allowing doctors to find and remove any polyps (growths) that might eventually become cancerous if left alone.

Early Detection of Cancer

Endoscopy can sometimes be used to find cancer early, before it has had a chance to grow or spread.

Looking for Causes of Symptoms

When people go to their doctor with certain symptoms, endoscopy can sometimes be used to help find a cause. Examples include laryngoscopy to look at the vocal cords in people with hoarseness, upper endoscopy in people having trouble eating, and colonoscopy in people with unexplained anemia (low red blood cell counts) or blood in their stool.

Looking at Problems Found on Imaging Tests

Imaging tests such as CT scans can sometimes show physical changes within the body. But these tests may only give information about the size, shape, and location of the problem. Doctors can use endoscopy to see more details, such as color and surface texture, when trying to find out what's going on.

Diagnosing and Determining the Stage (Extent) of Cancer

Going one step further, most types of endoscopes have tools on the end that allow the doctor to remove small tissue samples for biopsy (buy-op-see). The samples can then be viewed under a microscope or tested in other ways to know for sure whether or not cancer is present. A biopsy is usually the best way to find out if a growth is cancer or something else.

In some cases endoscopes are used to help find out how far a cancer may have spread. Thoracoscopy and laparoscopy can be especially useful in finding out whether certain cancers have spread into one of the body cavities (thorax or abdomen). They let the surgeon look at these spaces without making a large cut (incision) in the skin.

Some types of endoscopy can help make imaging tests more accurate. This can be especially helpful when trying to find the stage (extent) of cancer within the body.

Most people are familiar with ultrasound, an imaging test in which a wand (called a transducer) is moved over the skin. It sends sound waves into the body, which bounce back in a pattern that creates an image of the inside of the body. Endoscopic ultrasound (EUS) is a procedure in which a small transducer on the tip of an endoscope is inserted into the mouth or rectum. By putting the transducer on the tip of the endoscope, it can get closer to the area where the tumor is to take pictures.

Endoscopic ultrasound is used to get information about problems in the digestive tract and surrounding organs. Because the transducer is close to the organ being studied, it can make very detailed pictures. EUS can be used to see how deeply a tumor may have penetrated into the rectum or esophagus, or into an organ like the pancreas. It can also help show whether certain lymph nodes are enlarged. Endoscopic ultrasound is proving useful in staging some lung, digestive tract (esophagus, stomach, pancreas, etc.), and other cancers. EUS can also help a doctor guide a needle into a lymph node or other suspicious area to do a biopsy.

Endoscopic retrograde cholangiopancreatography (ERCP) is a complex procedure that helps doctors diagnose problems in the pancreas, gall bladder, or liver. In this procedure, an endoscope is passed down the throat, through the stomach, and into the first part of the small intestine. The doctor then guides a very small tube at the end of the endoscope into the common bile duct, which connects the intestine with the pancreas. A small amount of dye (contrast material) is then injected through the tip of the tube and x-rays are taken. This dye helps outline the bile ducts and pancreatic duct. The x-ray images can show narrowing or blockage of these ducts that might be due to a gallstone or a cancer. The doctor doing this test can also put a small brush through the tube to remove cells for biopsy (viewing under a microscope to see whether they look like cancer).

Treating Cancer

Endoscopes can be used to remove or destroy small cancers. Small instruments passed through an endoscope can be used to cut out small growths. Some forms of endoscopy allow doctors to use a cautery or laser through the tip of the endoscope to burn or vaporize growths.

Over the last decade or so, a wide variety of endoscopic tools have been developed that allow doctors to perform minimally invasive surgery. This type of surgery is sometimes called "keyhole" surgery, or, when used for the abdomen, is called laparoscopic surgery. Instead of using one long surgical incision, it involves making several small incisions in the skin – usually in the chest or abdomen. Long, thin instruments are then inserted through the holes to reach the inside of the body. A video endoscope (thoracoscope or laparoscope) is placed through one of the holes to allow the surgeon to see inside during the operation.

This type of surgery was first used for fairly minor procedures such as gall bladder removal, but in recent years doctors have begun using it to treat some types of cancer. It is now sometimes used to treat early cancers of the lung (this is called video-assisted thoracoscopic surgery, or VATS), colon (laparoscopic colectomy), prostate (called laparoscopic radical prostatectomy), and some other organs, although not all doctors agree on how suitable it is.

There are pros and cons to keyhole surgeries. There is generally less blood loss during the operation, and patients often recover faster and with less pain because the incisions are smaller than in regular surgery. Some forms of keyhole surgery use robotic arms, which a surgeon controls from a console. This technique allows for better magnification of the area and more precision in working with the delicate surgical instruments.

But it's not yet clear that keyhole surgery is better than regular surgery. It is harder for doctors to learn, and it usually involves more time in the operating room (and more time under anesthesia). It also takes away the surgeon's ability to feel organs for problems that may not be visible. Most studies done so far have not found keyhole surgery to be any less effective than regular "open" surgery, at least in the short-term, but as of yet there are no studies to show that the long-term outcomes are the same.

If you are thinking about some type of minimally invasive or keyhole surgery, it is important to understand the known benefits and risks, and what is not yet known about the procedure. If you decide on keyhole surgery, be sure your doctor has a lot of experience and is skilled with the technique.

Relieving Symptoms of Advanced Cancer

Endoscopes can also be used for palliative treatment (treatment given to reduce or control symptoms caused by the cancer) in some cases of advanced cancers that can't be cured by surgery. For example, instruments passed down endoscopes can be used to unblock obstructions in the lungs or digestive tract. If a tumor is pressing on the outside of an airway or duct causing it to narrow, endoscopy can be used to place a stent (a small, rigid tube) inside it to keep it open.

What Does the Procedure Involve?

Because there is such a wide range of endoscopy procedures, the experience of having an endoscopy can be very different from one type to the next. The table below summarizes some of the key elements of the more common forms of endoscopy. It does not include minimally invasive surgeries.

Type of Endoscopy	Special Preparation (Usually Starting the Night Before)	Usually Done in Operating Room?	Usual Type of Anesthesia	Approximate Length of Procedure
bronchoscopy	fasting	no	local + sedation or general	30 min to 2 hours
laryngoscopy	fasting	no	local or general	15 min to 1 hour
upper endoscopy	fasting	no	local + sedation	15 to 30 min
flexible sigmoidoscopy	liquid diet, laxative/enema	no	usually none	15 to 30 min
colonoscopy	liquid diet, laxative/enema	no	mild sedation	30 to 60 min
cystoscopy	fasting	sometimes	local or general	15 to 30 min
mediastinoscopy	fasting	yes	general	1 to 2 hours
thoracoscopy	fasting	yes	general	2 to 3 hours
laparoscopy	fasting	yes	general	20 min to 1 hour

It's important to keep in mind that there may be more than one way to do some procedures. For example, bronchoscopy and laryngoscopy can be done with either a flexible or rigid scope. Local anesthesia (numbing the local area) is generally used for flexible scopes, while rigid scopes often require general anesthesia (where you are given drugs to put you into a deep sleep).

Individual experiences may also vary depending on the person's health and what needs to be done (such as whether biopsy samples are going to be taken). If you are scheduled to have an endoscopy, your health care team will explain the specifics of what will be done and what you should expect before, during, and after the test. They will also tell you what you need to do to prepare for the procedure, such as fast (not eat anything) for a certain amount of time, follow a liquid diet for a certain amount of time, or use laxatives or enemas.

Newer Types of Endoscopy

In recent years, researchers have developed newer ways of looking at the inside of the body. While they are often referred to as newer forms of endoscopy, they don't insert tubes into the body.

Capsule Endoscopy

Doctors can reach much of the digestive tract using upper endoscopy or colonoscopy. But most of the 20 feet or so of small intestine can't be seen this way. Fortunately, cancers in this area are rare, but tumors and other problems such as ulcers can develop here.

One way to look at this area is to use capsule endoscopy. In this procedure, a person swallows a capsule (about the size of a large vitamin pill) that contains a light source and a very small camera. Like any other pill, the capsule goes through the stomach and into the small intestine. As it travels through the small intestine (usually over the course of about 8 hours), it takes thousands of pictures. These images are transmitted electronically to a device worn around the person's waist, while he or she goes on with normal daily activities. The pictures can then be downloaded onto a computer, where the doctor can look at them as a video. The capsule passes out of the body during a normal bowel movement and is flushed away.

This technique may be helpful in finding the source of bleeding, pain, or other symptoms that may be coming from the small intestine, but right now it's not useful for looking at the colon or other parts of the body. Because it is still a relatively new technique, not all insurance companies may cover it.

Virtual Endoscopy

Technically, virtual endoscopy is an imaging test. It uses a special CT scan to look at the inside surfaces of organs such as the lungs (virtual bronchoscopy) or colon (virtual colonoscopy, also called CT colonography). Patients have the procedure just as they would any other CT scan – that is, they lie still on a table while a large ring (the CT scanner) passes over the part of the body being imaged.

Unlike normal CT scans, which result in images in 2 dimensions, virtual endoscopy uses a computer to combine many images to create a 3-dimensional (3-D) picture. Doctors can even use the images to create a black and white "fly-through" view on the screen, which looks much like it would if they were performing an actual endoscopy.

Virtual endoscopy has some advantages over standard endoscopy in that it is non-invasive and doesn't require any type of anesthesia. It also allows the doctor to change the angle or magnify the image, which can help with diagnosis.

But there are some disadvantages too. While virtual endoscopy does show good detail, it's not quite as good at showing fine detail as standard endoscopy. (For example, it can't show color differences.) It also exposes the patient to some radiation--about the same amount as a standard CT. Finally, because it's not invasive, it doesn't allow the doctor to take biopsy samples while it is being done. This means that if something abnormal is found, the patient may still need a standard endoscopy so that a biopsy sample can be taken.

Virtual endoscopy is still a relatively new procedure, and doctors aren't yet sure how best to use it. It will likely be used more in the future as the technology continues to improve.

Additional Resources

More Information From Your American Cancer Society

The following information may also be helpful to you. These materials may be viewed on our Web site, http://www.cancer.org, or ordered from our toll-free number, 1-800-ACS-2345 (1-800-227-2345).

Imaging (Radiology) Tests

Testing Biopsy and Cytology Specimens for Cancer

References

Nguyen DM, Summers RM, Finkelstein SE. Respiratory tract. In: DeVita VT, Hellman S, Rosenberg SA, eds. Cancer: Principles and Practice of Oncology. 7th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2005:643-651.

Waxman, I. Gastrointestinal endoscopy. In: DeVita VT, Hellman S, Rosenberg SA, eds. Cancer: Principles and Practice of Oncology. 7th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2005:637-643.

Revised: 11/14/2007