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Pancreatic Cancer: Surgical Treatment
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Submitted By: C.J. Lee, M.D.
Surgical Treatment of Pancreatic Cancer
Authored by: C.J. Lee, M.D. and Diane M. Simeone, M.D.
University of Michigan Department of Surgery
In 2005, more than 33,000 people were diagnosed with pancreatic cancer and approximately 32,000 people succumbed to the disease, making it the 4th leading cancer killer. Pancreatic cancer develops when the tissues of the pancreas, a glandular organ that lies horizontally behind the lower part of the stomach, undergo malignant change. The pancreas is a vital organ that secretes enzymes that aid in digestion and also produces hormones, such as insulin, that help regulate carbohydrate metabolism in your body. Although there are different types of pancreatic cancer, the most common type is adenocarcinoma of the pancreas, which comprises approximately 95% of all pancreatic cancer. Pancreatic cancer is rarely detected in its early stages, which is a major reason why it is so difficult to treat. Signs and symptoms may not appear until the disease is quite advanced. Even with the advances in treating pancreatic cancer with chemotherapy and radiation therapy, only surgery offers a potential cure from the disease.
Symptoms of Pancreatic Cancer:
On presentation, patients may have a variety of symptoms as they are related to the extent of the disease and the location of the tumor in the pancreas. Common symptoms include jaundice (70-85%) and abdominal pain (75-90%), described as cramping or gas-like pain which may spread or radiate to the back. Jaundice develops as a result of tumor blockage of the bile ducts. Symptoms of jaundice include yellowing of the skin, eyes, light-colored (clay colored) bowel movements, dark colored urine, and itching. Patients may also have nausea, vomiting, and weight loss (35-34%) if the tumor grows to obstruct the duodenum, the first portion of the small intestine. This will lead to a delay in stomach emptying resulting in the symptoms as described. In more advanced disease, patients can develop fatigue. Other uncommon symptoms include spontaneous development of blood clots and development of diabetes, and pancreatic insufficiency.
Diagnosis and Classification of Pancreatic Cancer:
Patients with suspected pancreatic cancer will undergo a battery of tests aimed at obtaining the correct diagnosis as well as accurate staging if a diagnosis cancer is confirmed. The most common imaging studies that patients will undergo are abdominal ultrasound and/ or abdominal CT (computed tomography) scans. Ultrasound scans can identify a tumor or mass in the pancreas and bile ducts that maybe obstructive, however will not be able to determine resectability of the tumor. CT scans allow for higher resolution cross sectional images of the abdomen that can show small tumors, tumor involvement of surrounding structures including major blood vessels, as well as evidence of distant spread. This diagnostic test is of key importance in determining surgical resectability of pancreatic cancer. An MRCP is a relatively new test that give detailed image of the bile ducts, the pancreatic duct, and the gallbladder. This test is a special type of MRI (magnetic resonance imaging). ERCP (endoscopic retrograde cholangiopancreatography) and the EUS (endoscopic ultrasonography) are more invasive tests to aid in the diagnosis and staging of pancreatic cancer. Both tests entail the insertion of a scope through the mouth and into the small intestine to look at the bile ducts and surrounding structures. ERCP allows for biopsy and sampling of bile ducts and pancreatic ducts as will as for therapy to treat bile duct blockage by the use of stents. EUS is particularly useful in detecting small tumors which may not be well visualized by the CT scan. It can also elucidate involvement of the tumor to important structures including blood vessels. This test also allows for biopsy of the pancreas.
Pancreatic cancer can generally be classified into three groups: 1) resectable (the tumor is able to be surgically removed); 2) locally advanced - unresectable cancer (tumor has enlarged to the point of involving nearby critical blood vessels, which prevents complete surgical removal of the cancer, even though the cancer has not yet spread to distant organs); and 3) metastatic disease (cancer has spread to distant organs). For patients with localized advanced disease, treatment strategies using combination chemotherapy and radiation therapy may be offered to patients to try to downstage the disease and allow an attempt at subsequent surgical resection. For patients with metastatic disease, chemotherapy is the treatment of choice
Surgical Treatment:
Surgery for pancreatic cancer can be categorized into two types; curative resection and palliative procedures. The goal of a curative operation is to remove the tumor in its entirety with adequate margins. The patient will need to undergo various imaging studies including a CT scan or MRI to allow the surgeon to determine whether a curative resection is possible. There are several clinical trials underway to evaluate the possibility of “shrinking” tumors that were initially deemed unresectable with the use of preoperative chemotherapy and radiation therapy. This is to try and downstage the tumor to allow for surgical resection and to improve outcomes following curative resection. Although favorable results from these trials have been shown, the data is still preliminary.
Pancreaticoduodenectomy or commonly known as the Whipple procedure is the most common surgical procedure performed to attempt at curative resection of pancreatic cancer. As most pancreatic adenocarcinomas occur in the head of the pancreas, this is a surgical procedure in which the head of the pancreas, the gallbladder, part of the stomach, part of the small intestine (duodenum), and the bile duct are removed. Approximately 50% of the pancreas is removed, however the remainder of the pancreas often continues to produce enough digestive enzymes and insulin that the body requires. After resection of the tumor, 3 anastomosis (connections) must be made: the intestine to the pancreatic remanant, the bile duct, and the stomach.(figure 1)
Figure 1: The Whipple Operation
Sometimes a pylorus-preserving Whipple operation is performed, and the connection is made to the duodenum just distal to the stomach. The bile flow from the liver to the intestine is also maintained. This operation requires much skill and experience and should be performed by a pancreatic surgeon who regularly performs these procedures. On average, the Whipple procedure takes approximately 4-6 hours to complete.
The Whipple procedure is a major operation that carries a relatively high risk of complications. Recent studies have shown that when this operation is performed in small hospitals or by doctors with less experience, up to 15% of patients may die as a result of surgical complications. In high volume centers where this procedure is performed by experienced surgeons, the mortality rate is reduced to 1-3%. Even after successful completion of the operation, 30% to 40% of patients will suffer complications from the surgery which include bleeding, infection, or leak at the connection to the pancreas known as a pancreatic fistula (10-15%), bile duct (2-3%), or stomach (rare). Because of the aggressiveness of pancreatic cancer, even in those patients undergoing curative Whipple surgery, the 5-year survival rate is about 20%.
For pancreatic tumors that occur at the tail of the pancreas, a distal pancreatectomy can be performed. This operation resects the tail and sometimes a portion of the body of the pancreas. The spleen is often removed as well as it lies adjacent to the tail of the pancreas.
A total pancreatectomy may be performed for tumors that involve the body and head of the pancreas, however it is rarely indicated for patients with pancreatic cancer.
Only about 15% of cancers of the pancreas appear to be contained entirely within the pancreas at the time of diagnosis. Even when there appears to be no spread beyond the pancreas at the time of surgery, cancer cells may already have spread to other parts of the body. Sometimes the tumor appears resectable by CT scan, but the patient is found to have metastatic disease when a Whipple procedure is attempted. This occurs about 10-15% of the time and is usually because the metastic lesions are too small (<1cm) to be seen on CT scan. If the cancer has spread and cannot be removed at the time of diagnosis, the patient may be offered various palliative procedures.
In its advanced stages pancreatic cancer may grow and obstruct the common bile duct, the major conduit that drains bile from the liver. When this occurs, the patient becomes jaundiced (skin turns yellow) and may experience itching. If the tumor is blocking the bile duct, a stent may be placed endoscopically by a gastroenterologist. (figure 2)
Figure 2: Bile duct stent placed to relieve obstruction
If endoscopic stent placement cannot be performed, radiologists may need to place the stents through the skin and liver into the bile duct for drainage, a procedure called percutaneous transhepatic cholangiography (PTC) (Figure 3).
Figure 3: PTC (percutaneous transhepatic cholangiography) tube placement for biliary drainage
If the cancer is deemed unresectable, patients can be offered a biliary bypass. The purpose of this operation is to reroute the bile flow from the liver to the intestine around the obstructing area. The surgeon will cut the gallbladder or bile duct and sew it to the small intestine to create this bypass. If it appears that the tumor may also be blocking the first part of the small intestine, a gastric bypass procedure may be performed where the stomach is sewn directly to the small intestine around the obstructive tumor so the patient can continue to eat normally. The two operations are often performed in conjunction and together the surgery may sometimes be referred to as a double bypass operation.
The postoperative recovery and side effects of surgical treatment depend on the type and extent of the operation, and the person's general health. Regardless, patients typically need to stay in the hospital for several days afterward for postoperative monitoring and care. Pain following the operation will become an important issue but can be effectively controlled with medicine. It is not uncommon for patients to not eat for 4-5 days following the procedure as new intestinal connections have been made and those connections will need time to heal. In addition, the gastrointestinal tract commonly has decreased motility, termed ileus, for the first few days after an abdominal operation. Ileus is a state when the peristaltic movements that allow for passage of food are uncoordinated, and thus food and digestive juices may back up. As such, in the first few days following surgery, a patient may have only liquids and may receive extra nourishment intravenously or by feeding tube into the intestine. After discharge from the hospital, the recovery time to full return to normal function is typically 2-3 months.
Summary:
All in all, surgical treatment for pancreatic cancer is currently the only potential option for cure. Preoperative CT scanning helps determine which patients may be candidates for surgical treatment. The operative procedure is best performed by a surgeon at a hospital that has extensive experience with pancreatic surgery to optimize surgical results.
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Additional Authors: |
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Works Cited: |
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Jemal, A, Siegel, R, Ward, E et al. Cancer statistics, 2006. CA Cancer J Clin 2006; 56:106.
Birkmeyer, JD, Stukel, TA, Siewers, AE, et al. Surgeon volume and operative mortality in the United States. N Engl J Med 2003; 349:2117.
Yeo, CJ, Cameron, JL, Sohn, TA, et al. Six hundred fifty consecutive pancreaticoduodenectomies in the 1990s: pathology, complications, and outcomes. Ann Surg 1997; 226:248.
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