Pancreatic cancer is the fourth leading cause of cancer-related death.Most patients with pancreatic cancer are often diagnosed at an advanced stage. Surgical resection is the only curative treatment.
The pancreas is a gland located in the upper abdomen behind the stomach and in front of the spine. It measures 15 x 4 cm, weighs 60-140 gm and is divided into 3 major parts- head, body and tail. Almost 95% pancreatic cancers arise from exocrine cells which produce digestive juices and are classified as the adenocarcinoma type. Other types of pancreatic cancer include ampullary cancer, pancreaticoblastoma, lymphoma and sarcoma. Approximately 5% pancreatic tumors arise from endocrine cells which produce hormones and are known as neuroendocrine (NET) or islet cell tumors. Pancreatic NET include insulinomas, glucagonomas, gastrinomas, VIPomas and somatostatinomas.
Risk factors for pancreatic cancer include smoking, diabetes mellitus, chronic pancreatitis and a family history of pancreatic cancer. Symptoms of pancreatic cancer include upper abdominal pain radiating to the back, yellow discoloration of eyes and skin (jaundice) and loss of appetite or weight.
Pancreatic Cystic Neoplasms
The most common types of cystic neoplasms of the pancreas are:
- Serous cystadenoma
- Mucinous cystic neoplasms
- Intraductal papillary mucinous neoplasms
- Solid pseudopapillary neoplasms (Hamoudi or Frantz tumors)
Most serous cystadenomas do not require surgical resection unless they are symptomatic as malignant degeneration is exceedingly rare. Mucinous cystic neoplasms occur exclusively in women and are at risk for malignant degeneration. The prognosis is excellent if they are removed prior to development of tumor invasion.
Intraductal papillary mucinous neoplasms (IPMN) are potentially malignant neoplasms comprised of papillary proliferation of mucin-producing columnar cells. Two-thirds of the IPMNs are of the branch-duct type with a low incidence of cancer and the remaining are of the main-duct type which are at increased risk for cancer. Most IPMNs do not require surgical intervention however, surgery is the only curative treatment for IPMNs at increased risk for cancer.
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In addition to a CT scan, any of the following diagnostic modalities maybe used in the evaluation of patients with suspected pancreatic cancer.
CT scan is performed to assess the characteristics and extent of tumor and is highly accurate in the preoperative assessment of tumor resectability. Alternatively, a MRCP- Magnetic Resonance Cholangiopancreatography may be performed.
Endoscopic Retrograde Cholangiopancreatography
ERCP may be used to visualize the ampulla, obtain biopsy or place endobiliary stents to relieve jaundice.
Staging laparoscopy may identify tumor deposits not seen on imaging and avoid major operative intervention in patients with inoperable pancreatic cancer.
Tissue diagnosis is required prior to the administration of chemotherapy or radiation therapy.
TNM staging system of pancreatic cancer is based on the size of the tumor (T) and its extension to major arteries or veins, involvement of regional lymph nodes (N) or presence of distant metastases (M).
Based on whether the pancreatic tumor can be removed surgically or not, it is classified into the following categories:
- Borderline resectable
- Locally advanced (unresectable)
- Distant metastatic (unresectable)
Survival depends upon the stage of the pancreatic cancer at diagnosis and the best outcomes are achieved with a multidisciplinary approach utilizing a combination of surgical removal of the tumor, chemotherapy and radiation therapy. Curative surgery involves removal of the tumor-bearing part of the pancreas with negative pathologic margins.
There are various types of pancreatic resections and the two most commonly performed operations for pancreatic cancer are the Whipple surgery or pancreaticoduodenectomy and distal pancreatectomy depending on the location of the tumor. The Whipple surgery is performed for tumors located in the head of the pancreas and distal pancreatectomy for tumors in the pancreatic tail or body. As the head of the pancreas lies in close association with the first portion of the small intestine (duodenum), lower part of the stomach and bile duct these structures have to be removed in continuity in a Whipple surgery to avoid tumor spillage.
1. Whipple Surgery
If the tumor is located in the head of the pancreas a Whipple surgery or pancreaticoduodenectomy is required which removes the head of the pancreas with the tumor and portions of the bile duct, stomach and duodenum. The pancreatic remnant, bile duct and stomach are then reconnected to a loop of small intestine to restore gastrointestinal continuity.
2. Distal Pancreatectomy
If the cancer is located in the tail of the pancreas, a distal pancreatectomy is required involving removal of the tail and body of the pancreas with the spleen.
3. Central or Total Pancreatectomy
Occasionally if the tumor is multifocal or involves the entire pancreas a total pancreatectomy may be required and a central pancreatectomy may be performed
for cystic neoplasms or neuroendocrine tumors.
The chemotherapy drug most commonly used in the treatment of pancreatic cancer is gemcitabine and it may be used in combination with other drugs such as fluorouracil, cisplatin or targeted agents such as erlotinib.
External beam radiation therapy is administered in fractions and the total dose is given over 5-6 weeks following surgical removal of the tumor. In a preoperative setting, when radiation is administered concurrent with chemotherapy the objective is shrinkage of the pancreatic cancer to improve its chances of complete resection.
Therapeutic measures to relieve the symptoms of advanced or recurrent pancreatic cancer are usually non-operative. These include the endoscopic placement of biliary or intestinal stents to relieve obstruction and celiac axis nerve blocks to relieve abdominal or back pain.
For more information visit: Pancreatic Cancer | Cancer.net