Exocrine Neoplasms
posted in The Aging Liver |The only significant benign exocrine pancrealic neoplasm is cystade-nqma, which usually occurs in the body and tail of the pancreas in middle-aged and elderly women. Surgical resection may be needed for diagnosis and relief of symptoms from a large mass.
Pancrealic cancer is the second most common dl cancer in the USA with about 28,000 new cases diagnosed annually. The incidence increases with age and is 10 times greater in men > 75 yr than in the general population. Risk factors include cigarelle smoking, diabetes mellitus, and a diel high in animal fat and alcohol.
Ductal cell adenocarcinoma accounts for 75% to %% of all cancers arising from the pancreas. Others include giant cell carcinoma, adeno-squamous carcinoma, cysladenocarcinoma, and lymphoma. Giant cell carcinoma, also called carcinosarcoma, is a highly malignant lesion with distant metastases occurring early. Adenosquamous carcinoma occurs predominantly in men. more often in patienls wilh a history of radiation therapy. Cystadenocarcinoma, a low-grade malignancy, has the best prognosis because only 20% have metastasized by the time of surgery. Lymphoma of the pancreas accounts for 2% of all non-Hodgkin’s lymphoma and may be of B-cell or T-cell origin.
Symptoms and Signs
The clinical features of pancreatic cancer often depend on the location of the lesions; 80% occur in the head of Ihe pancreas, and 20% in Ihe body and tail. Patients with lesions of the pancreatic head often present with painless jaundice and acholic stools from common duct obstruction or with nausea and vomiting from gastric outlet obstruction. Itching may accompany jaundice. The onset of symptoms in those with lesions of the body and tail is more insidious, amounting to little more than weight loss and vague abdominal or back pain. Symptoms precede diagnosis by about 3 to 6 mo. In 90% of patients with ductal eel I adenocarcinoma, metastases are present at diagnosis, so death Often occurs within 6 mo.
Findings associated with pancreatic cancer include depression, thromboembolic phenomena associated wilh Trousseau’s syndrome, GI bleeding from gastric varices secondary to splenic vein thrombosis, polyarthritis, diarrhea caused by exocrine pancreatic insufficiency, superior vena cava syndrome caused by mediastinal metastases, and Homer’s syndrome caused by thoracic outlet metastasis. The onset of diabetes mellilus or a worsening of preexisting diabetes warrants an evaluation for pancreatic cancer.
Early in the disease the physical examination is negative. Later, an epigastric mass, supraclavicular lymphadenopathy, hepatomegaly from biliary stasis or metastasis, or a large, palpable gallbladder may be noted. Painless jaundice and a palpable gallbladder (Courvoisier’s sign) combined with acholic stools are diagnostic. Silver-colored stools may be noted in cancer of the ampulla of Vater because of the combination of mild bleeding and acholic stools.
Diagnosis
F.arly diagnosis when the tumor is still resectable is rarely possible. It is possible only wiih cancer of the pancreatic head associated with jaundice and with cancer of the ampulla of Vatcr. which may cause early i;iundiee. Diagnosis may be suggested by upper abdominal sonography, although a CT scan of the abdomen can better visualize a pancreaiu muss. In up to 90% of cases, endoscopic retrograde cholangiopancreatography can detect the tumor with the characteristic findings of dm till irregularity and cutoff. Although tissue for diagnosis can usually be obtained by needle biopsy, exploratory laparotomy is often necessary Serologic tumor markers including CEA, CA19-9, and galaetosyltransfeiase isoenzyme II (Gl-ll) may be elevated in some cases but are rarel> useful clinically.
Treatment
Patients who have nonmetastatic, resectable lesions in the pancreatic head may be candidates for pancreatoduodenectomy (Whipple’s operation). Only 10% of patients with ductal cell carcinoma have localized tumors. In most patients, the only procedure that can be performed is a palliative bypass (eg, cholecystojejunostomy for distal hile duct obstruction or gastrojejunostomy for gastric outlet obstruction); however, surgery is usually not warranted, and obstructive jaundice can be managed with an endoscopically placed stent. In older persons with nonrescctable tumors, forgoing all attempts at cure is often besl.
Chemotherapy produces little response and no long-term benefit in patients with adenocarcinoma. Radiation therapy offers minimal benefit, except for palliation of retroperitoneal pain. Palliative treatment wilh a biliary stent (placed endoscopically or radiological]y using transhepatic cholangiography) may reduce jaundice and itching.
Generally, abdominal pain is treated with analgesics and oral narcotics. However, a celiac axis nerve block maybe needed for severe, unrelenting pain. Pruritus from jaundice may be relieved wilh antihistamines or cholestyramine 4 gin orally I to 4 times daily. Pancreatic insufficiency can be managed with pancreatic enzymes (lipase, protease, and amylase).
The overall prognosis is dismal for adenocarcinoma; the I-yr survival rate is < 10%, and the 5-yr survival rate is only 2%. Cystadenocarcinoma. which has a low incidence of metastasis at diagnosis, has a 5-yr survival rate of 65% with aggressive surgery. Lymphoma also has a good prognosis.
