Pancreatic cancer

Pancreatic cancer

Pancreatic cancer is a malignant neoplasm of the pancreas. Each year in the United States, about 42,470 individuals are diagnosed with this condition and 35,240 die from the disease. The prognosis is generally poor; less than 5 percent of those diagnosed are still alive five years after diagnosis. Complete remission is still extremely rare.
About 95% of exocrine pancreatic cancers are adenocarcinomas (M8140/3). The remaining 5% include adenosquamous carcinomas, signet ring cell carcinomas, hepatoid carcinomas, colloid carcinomas, undifferentiated carcinomas, and undifferentiated carcinomas with osteoclast-like giant cells.^[3] Exocrine pancreatic cancers are far more common than endocrine pancreatic cancers (also known as islet cell carcinomas), which make up about 1% of total cases.

Signs and symptoms

Pancreatic cancer is sometimes called a "silent killer" because early pancreatic cancer often does not cause symptoms,^[5] and the later symptoms are usually non-specific and varied.^[5] Therefore, pancreatic cancer is often not diagnosed until it is advanced.^[5] Common symptoms include:

• Pain in the upper abdomen that typically radiates to the back^[5] (seen in carcinoma of the body or tail of the pancreas)
• Loss of appetite and/or nausea and vomiting^[5]
• Significant weight loss
• Painless jaundice (yellow skin/eyes, dark urine)^[5] when a cancer of the head of the pancreas (about 60% of cases) obstructs the common bile duct as it runs through the pancreas. This may also cause pale-colored stool and steatorrhea.
• Trousseau sign, in which blood clots form spontaneously in the portal blood vessels, the deep veins of the extremities, or the superficial veins anywhere on the body, is sometimes associated with pancreatic cancer.
• Diabetes mellitus, or elevated blood sugar levels. Many patients with pancreatic cancer develop diabetes months to even years before they are diagnosed with pancreatic cancer, suggesting that new onset diabetes in an elderly individual may be an early warning sign of pancreatic cancer.^[6]
• Clinical depression has been reported in association with pancreatic cancer, sometimes presenting before the cancer is diagnosed. However, the mechanism for this association is not known.^[7]

Diagnosis

Most patients with pancreatic cancer experience pain, weight loss, or jaundice.^[32]
Pain is present in 80 to 85 percent of patients with locally advanced or advanced metastic disease. The pain is usually felt in the upper abdomen as a dull ache that radiates straight through to the back. It may be intermittent and made worse by eating. Weight loss can be profound; it can be associated with anorexia, early satiety, diarrhea, or steatorrhea. Jaundice is often accompanied by pruritus and dark urine. Painful jaundice is present in approximately one-half of patients with locally unresectable disease, while painless jaundice is present in approximately one-half of patients with a potentially resectable and curable lesion.
The initial presentation varies according to location of the cancer. Malignancies in the pancreatic body or tail usually present with pain and weight loss, while those in the head of the gland typically present with steatorrhea, weight loss, and jaundice. The recent onset of atypical diabetes mellitus, a history of recent but unexplained thrombophlebitis (Trousseau sign), or a previous attack of pancreatitis are sometimes noted.
Courvoisier sign defines the presence of jaundice and a painlessly distended gallbladder as strongly indicative of pancreatic cancer, and may be used to distinguish pancreatic cancer from gallstones.
Tiredness, irritability and difficulty eating due to pain also exist. Pancreatic cancer is usually discovered during the course of the evaluation of aforementioned symptoms.
Liver function tests can show a combination of results indicative of bile duct obstruction (raised conjugated bilirubin, γ-glutamyl transpeptidase and alkaline phosphatase levels). CA19-9 (carbohydrate antigen 19.9) is a tumor marker that is frequently elevated in pancreatic cancer. However, it lacks sensitivity and specificity. When a cutoff above 37 U/mL is used, this marker has a sensitivity of 77% and specificity of 87% in discerning benign from malignant disease. CA 19-9 might be normal early in the course, and could be elevated due to benign causes of biliary obstruction.^[33]
Imaging studies, such as computed tomography (CT scan) can be used to identify the location of the cancer. Endoscopic ultrasound (EUS) is another procedure that can help visualize the location and can serve to guide a percutaneous needle biopsy, which is necessary to establish a definitive diagnosis.