Examination of pancreatic cancer

Pancreatic exocrine adenocarcinoma ranks second among common visceral malignancies and fifth among causes of cancer deaths in the United States, accounting for one-fifth of deaths from gastrointestinal cancers. The location of the pancreas behind the peritoneum makes it difficult to get early treatment, however, recent medical advances have had a lot of impact on the diagnosis and treatment of this difficult-to-treat disease.

1. Clinical manifestations

The clinical manifestations of pancreatic cancer depend on the initial site of the cancer, the obstruction caused by the cancer, the degree of pancreatic damage, and the presence or absence of metastatic cancer. The most common clinical symptoms of this disease are abdominal pain, weight loss, and jaundice, followed by fatigue, loss of appetite, back pain, nausea, vomiting, abdominal distension, diarrhea, constipation, abdominal mass, fever, etc.

(1) Abdominal pain: About 3/4 of patients may experience discomfort and dull pain in the upper abdomen. Almost all cases of pancreatic body and tail cancer have abdominal pain, and it occurs early. The pain is usually mild at the beginning, only manifesting as discomfort in the upper abdomen, and then gradually worsens. The typical location of the pain is in the upper and middle abdomen and left hypochondrium, and can radiate to the back, chest and shoulder blade. The nature of the pain is often unclear in the early stage. Dull pain or dull pain can then develop into paroxysmal colic or continuous dull pain, which often worsens in the supine position and at night, and can be relieved when lying prone, sitting, standing, leaning forward and walking. This is particularly typical in pancreatic body and tail cancer.

(2) Weight loss: About 90% of patients experience rapid and significant weight loss, some of which may not be accompanied by jaundice or abdominal pain. For a period of time, weight loss is the only symptom. Therefore, for those who experience progressive weight loss for unknown reasons, especially men over 40 years old, it is important to be alert to the possibility of pancreatic cancer. Late-stage patients often develop cachexia.

(3) Jaundice: About 70% of patients experience varying degrees of jaundice at some stage in the course of the disease. Jaundice is usually more common in pancreatic head cancer. Early pancreatic head and tail cancer usually do not cause jaundice. In the late stage, due to the invasion of the pancreatic head or metastasis to the liver, bile duct, lymph nodes, etc., obstructive jaundice may also occur. Once jaundice occurs, it often progressively deepens. In some cases, it may temporarily alleviate or disappear.

(4) Other symptoms: Other common symptoms include:

1) Gastrointestinal symptoms: including loss of appetite, aversion to oily food, nausea, vomiting, abdominal distension, diarrhea, constipation, etc. If the tumor invades the gastrointestinal tract, vomiting blood or black stools may also occur

2) Fever: Most cases present as intermittent or persistent low-grade fever. If accompanied by biliary tract infection or lung infection, chills and high fever may occur.

3) Abdominal mass: In the middle and late stages of pancreatic cancer, a mass may be felt in the upper abdomen. The mass may be an enlarged gallbladder, liver, or the cancer itself.

4) Mental symptoms: Many patients may experience anxiety, insomnia, depression, etc.

2. Laboratory examination

1. Blood test

(1) Serum bilirubin: Due to obstruction of the lower end of the bile duct, patients with pancreatic head cancer have a progressive increase in serum bilirubin, mainly due to an increase in direct bilirubin content.

(2) Blood sugar: In most cases, abnormal glucose tolerance tests will occur in the early stages. Hyperglycemia may occur due to the destruction of the pancreatic islets by the cancer.

(3) Serum carcinoembryonic antigen (CEA): It is usually positive, but not very specific, because most digestive tract tumors can have elevated CEA. A positive digestive tract cancer-associated antigen (CA19-9) is considered to be a more specific indicator for diagnosing pancreatic cancer.

(4) Blood enzyme examination: Amylase, lipase, r-glutamyl transpeptidase (r-GT), galactosyltransferase isoenzyme II, etc. may all be increased.

2. Urine test

When obstructive jaundice occurs, urine bilirubin increases significantly, but no urobilinogen. When blood sugar increases, urine sugar is positive. In patients with middle and late stage pancreatic exocrine function decline, the urine BT-PABA test results may be significantly lower than normal.

3. Imaging diagnostic examination

(1) B-ultrasound examination: It is a non-invasive examination and is the first choice for pancreatic cancer. Most pancreatic cancers found by ultrasound examination are larger than 2 cm, and small tumors are often difficult to detect. B-ultrasound can also detect pancreatic duct dilatation, bile duct [intrahepatic and/or extrahepatic] dilatation, gallbladder enlargement, and intrahepatic metastasis. B-ultrasound examination finds bile duct dilatation without jaundice and cholelithiasis, which may be an early sign of periampullary cancer and should be vigilant and further examination should be performed.

(2) CT examination: The CT manifestations of pancreatic cancer are as follows: ① The lesion is a mass shadow, which is often irregular in shape and often has lobes. It is located in the pancreatic parenchyma, and the shape of the pancreas changes; ② The density of the tumor is mostly lower than that of normal tissue. If there is necrosis, a lower density area can be seen, and the edge of the necrotic area is irregular; ③ Dilatation of the pancreatic duct and bile duct can be seen. When the pancreatic duct is dilated due to tumor infiltration and compression, the distal pancreatic duct dilation often presents a tubular or beaded low-density shadow. When pancreatic head cancer invades the lower end of the common bile duct, the upper part of the common bile duct is dilated, and the intrahepatic bile duct is also dilated; ④ After injection of contrast agent, the cancer tissue is not as good as normal tissue, but forms a clear contrast with normal tissue, which can clearly show the outline of the tumor and its relationship with surrounding tissues.

(3) ERCP: It has a certain value in the diagnosis of pancreatic cancer. It can detect interruption, stenosis, rigidity, dilation or displacement of the main pancreatic duct, all of which indicate the possibility of a tumor in the pancreatic body and tail. Pancreatic head cancer often blocks the opening of the pancreatic duct, making endoscopic imaging difficult. If filling defects, stenosis or compression of the lower end of the bile duct are found during endoscopic cholangiography, this is evidence of periampullary cancer.

In short, pancreatic cancer often has an insidious onset and often has no characteristic manifestations in the early stages. Once obstructive jaundice or a mass in the upper abdominal area appears, the surrounding tissues have already been infiltrated. Clinically, men over 40 years old who have one or more of the above clinical symptoms, especially those who have unexplained weight loss in the recent period, or those who have symptoms of indigestion accompanied by positive CEA and increased r-GT activity, or those who have abnormal glucose tolerance tests or increased blood sugar in the recent period, should be alert to the possibility of pancreatic cancer.