Wednesday, October 26, 2011

Biopsy for Pancreatic Cancer Diagnosing and Staging


Imaging tests are important in diagnosing suspected pancreatic cancer, but they cannot determine with 100% certainty if an abnormal mass is cancer or the type of cancer. During a biopsy, a small portion of a suspicious mass or cyst is removed and examined under a microscope for the presence of cancerous tissue. A biopsy can provide your doctor with an exact diagnosis. However, it is important to note that obtaining a conclusive tissue sample can be difficult. If cancerous tissue is found, the shape, size, and arrangement of the cells may help your doctor determine the type and stage of pancreatic cancer present.

If you have a cancer that is not removable with surgery, your specialist may want to biopsy it so that you can go on to have cancer treatment to try to slow down its growth. If all your other test results point to cancer and your consultant thinks there is no doubt that this is what you have, you may not need a biopsy before you have treatment.

There are several biopsy methods. Depending on the location of the mass and your personal health history, your doctor may use any of the following methods to provide the most accurate diagnosis.

Fine Needle Aspiration (FNA)

FNA is the most common biopsy procedure due to its safety and the reliability of its results. There are two ways to perform an FNA biopsy of the pancreas, either percutaneously (through the skin) or EUS-guided (with endoscopic ultrasound assistance).

During a percutaneous fine-needle aspiration, a local anesthetic and a cleaning solution are applied on the skin.  Then, a thin needle is inserted through the abdominal wall while the doctor uses the image from a CT scan or ultrasound to guide placement of the needle.  The needle is directed into the pancreas so that cells can be removed from the tumor.

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The EUS-guided fine-needle aspiration method involves passing the needle down the throat through a special endoscope during an endoscopic ultrasound (EUS) imaging procedure.  This process involves imaging the tumor with ultrasound and inserting a thin needle through the stomach or duodenal wall immediately next to the pancreas.  Unlike percutaneous FNA, there is no pain with EUS-guided FNA.  EUS-guided fine-needle aspiration performed by a specially-trained and experienced doctor has been shown to be the most accurate biopsy method for the pancreas.

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Brush Biopsy

In a brush biopsy, a small brush is inserted through the endoscope during an ERCP procedure and directly into your bile duct or pancreatic duct. Cells rub off onto the brush and can be examined using a microscope. However, the chance of getting a conclusive diagnosis using ERCP is low compared to FNA.

Forceps Biopsy

In a forceps biopsy, forceps are passed through the endoscope and a small piece of tissue is removed.  A tissue sample can also be taken during surgery.

Laparoscopy

Laparoscopy is a procedure in which a small camera attached to a thin, lighted tube is inserted directly into the abdominal cavity through a small incision. It is performed with the patient under general anesthesia. This means the patient is completely asleep during the procedure and does not respond to verbal or physical prompts. By manipulating the camera, the doctor can directly view the pancreas and its surrounding organs. Sometimes gas is pumped into the abdomen to make it swell and give more room for your doctor to look around. This gas will not do any harm and will gradually disperse and disappear after the test. Your doctor may use an ultrasound through the laparoscope. This will help to show exactly where the cancer is, so that your doctor can take a biopsy more accurately. A tissue biopsy can be taken by passing a pair of forceps through the laparoscope. After this test is over, you will have stitches or steristrips holding the incisions closed. They will heal within a week or so.

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Laparotomy

If your disease cannot be diagnosed any other way, you will have an operation called a laparotomy. This is an operation to open the abdomen and take a tissue sample from the pancreas. This is not often done these days. Laparoscopy is usually done instead because it is a much smaller operation. You have to come into hospital for a laparotomy and stay in for a few days afterwards. Some surgeons will send the biopsy to the laboratory while you are still under anaesthetic. If they get a positive diagnosis, they may continue to do the surgery you need for your cancer. Laparotomy is now rarely recommended as doctors prefer using Laparoscopy instead.

Most doctors who treat pancreatic cancer try to avoid surgery unless imaging tests suggest that an operation might be able to remove all of the visible cancer. Even after doing imaging tests and laparoscopy, there are times when the surgeon begins an operation with the intent of removing the cancer but finds during surgery that it has spread too far to be removed completely. In these cases, a sample of the cancer is taken only to confirm the diagnosis, and the rest of the planned operation is stopped.


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