Pancreatic Cancer - Diagnosis

Laboratory data for pancreatic cancer usually show an increase in ESR, and iron deficiency anemia is often detected, especially pronounced during tumor disintegration and bleeding. Even in the absence of obvious signs of anemia, coprological examination often reveals signs of hidden bleeding. Laboratory signs of blood hypercoagulation are relatively common.

In tumors affecting a significant part of the pancreatic parenchyma or in case of compression of the main duct, symptoms of its exocrine insufficiency, "pancreatogenic" diarrhea, steatorrhea, creatorrhea occur. In case of compression or germination of the terminal part of the common bile duct or CBD, cholestasis, hyperbilirubinemia (due to direct and partial unconjugated bilirubin), hypercholesterolemia occur; the stool becomes discolored. Often the content of amylase, trypsin and lipase in the blood serum, as well as amylase in the urine (in a single or 24-hour portion of it) is increased, especially in case of compression of the gland ducts by the tumor. Of some importance is the study of enzyme activity in the duodenal contents before and after stimulation of the gland with secretin and pancreozymin, as well as a synthetic drug similar in action to pancreozymin - cerulein; in many cases, a decrease in the secretion of pancreatic juice is determined, and the activity of enzymes in it decreases to a lesser extent. However, this study is quite difficult to conduct and is currently used only in a few medical institutions. In addition, these data, indicating excretory insufficiency of the pancreas, are only indirect signs of its damage and can be found in other diseases of the pancreas. An increase in the activity of serum amylase and hyperamylasuria are also not pathognomonic for pancreatic cancer. Moreover, to a moderate degree, they can be determined in many diseases of the abdominal organs.

Cytological examination of duodenal contents has some diagnostic value, however, tumor cells are not detected in it in all cases of this disease.

Disturbances in carbohydrate metabolism (hyperglycemia or glycosuria) indicate damage to the endocrine function of the gland (primary or secondary). These symptoms are observed in 30-50% of cases of adenocarcinoma. They become more significant if they occur shortly before other manifestations of the underlying disease.

In the absence of jaundice and liver metastases, liver function tests may remain normal. Attention should be paid to the activity of ribonuclease and alkaline phosphatase. The latter may be elevated several months before other signs of the tumor appear. Increased activity of other enzymes, increased levels of a2-globulin, increased ESR, anemia and leukocytosis are more common in stages III-IV and are not specific for pancreatic cancer.

Recently, much attention has been paid to tumor markers in recognizing its cancerous lesion.

Among the instrumental methods of pancreatic cancer diagnostics, traditional X-ray examination is the most accessible and includes a number of valuable techniques. With a polypositional X-ray examination of the stomach and duodenum, displacements, depressions and deformations of these organs, expansion of the duodenal loop; infiltration and ulceration of the wall are revealed. However, this method can only detect advanced stages of pancreatic cancer (mainly its head).

X-ray diagnostic methods are constantly being improved. Over 30 years ago, duodenography under artificial hypotension (filling the duodenum through a duodenal probe after preliminary intravenous administration of 2 ml of 0.1% atropine sulfate solution) began to be used to detect pancreatic head cancer (as well as some other diseases). In this case, it is possible to very clearly trace the course of the duodenal walls, atonic and stretched with a contrast mass, and determine the slightest indentations on its inner wall caused by an increase in the head of the pancreas, as well as the double-contour of the medial wall. When a tumor grows into the wall of the duodenum, Frostberg's symptom is often detected. In advanced cases, severe stenosis of the duodenum is sometimes determined. If cancer of the body or tail is suspected, splenoportography and selective angiography are performed, which are more complex methods and sometimes cause complications. Intravenous cholegraphy was once widely used when there was a suspicion of narrowing of the terminal part of the common bile duct due to compression or tumor invasion of the head of the pancreas. However, these conventional methods of contrasting the bile ducts are ineffective in obstructive jaundice; therefore, percutaneous hepatocholangiography is used to determine the level of obstruction. In case of cancer of the head of the pancreas, a characteristic break in the image is revealed - a "stump" of the common bile duct at the intrapancreatic or retroduodenal level; however, this method can also cause complications. Therefore, it can be used only for very strict indications.

Selective angiography of the celiac trunk and splenic artery allows to determine the localization, the extent of the process and makes it possible to judge its operability. The accuracy of this complex method in the hands of an experienced researcher reaches 89-90%. Signs of cancer in angiography are the detection of avascular zones, vascular infiltration (symptom. "usurization", symptom "stump", etc.). The above signs can be detected mainly when the tumor diameter reaches 5 cm or more. Differential diagnostics of pancreatic cancer and pseudotumor form of chronic pancreatitis is difficult, the angiographic signs of which coincide in 10% of cases. Angiography is accompanied by complications in almost 7%.

However, every year the possibility of direct examination of the main duct and tissue of the pancreas increases, instrumental methods of examination are improved and significantly increase the accuracy of diagnosis. In the last 20-15 years, the developed and increasingly widespread methods of ultrasound and CT have practically replaced complex and not entirely safe methods, significantly increasing the accuracy of pancreatic cancer diagnosis. With the help of these methods, focal formations of the pancreas with a diameter of 1.5-2 cm and more are detected with almost 100% accuracy (erroneous conclusions are rare and account for only a few percent of cases). Even more accurate is the MRI method, which allows you to detect focal formations in the organ with a diameter of only a few millimeters. However, the equipment for this study is very expensive and is currently available only in the largest hospitals and diagnostic centers.

A method of scanning the pancreas with radioactive ⁷⁵ 8e-methionine, which accumulates relatively well in the pancreas, but is rarely used at present. Focal defects in the pancreas in case of cancer and other changes are detected quite well using echography. A great advantage of ultrasound, in addition to high diagnostic accuracy, is the possibility of repeated use without any harm to the patient, and sometimes, if necessary, of assessing the pathological process in dynamics - and multiple use. Using echography, it is possible to detect tumor metastases in the liver and some other organs. Ultrasound is used both for preliminary and final diagnosis of pancreatic cancer. Under ultrasound or CT control, if necessary, a puncture biopsy of the pancreas is performed, and if liver metastases are suspected - of the liver. With the help of gastroduodenoscopy in case of pancreatic head cancer, it is possible to note some indirect signs allowing to suspect this disease: deformation, indentation and disturbance of peristalsis of the posterior wall of the stomach and duodenum, enveloping the head of the pancreas. This method is currently almost never used specifically for diagnostics of this disease due to the inaccuracy of the results. However, during an indicative diagnostic examination of the patient, when the diagnosis is unclear, but there are vague dyspeptic complaints, pain in the upper abdomen, in some cases this method allows to suspect a tumor lesion of the head of the pancreas and gives the doctor the opportunity to outline a plan for conducting special targeted studies. In some cases, the ERCP method is used, in which a contrast agent is injected into the main duct and its branches through a special catheter using modern flexible duodenofibroscopes. The radiographs taken later can also reveal “breaks” (non-filling) of some ducts and foci of tumor infiltration. ERCP is one of the relatively accurate methods for diagnosing pancreatic cancer; it helps establish the correct diagnosis in almost 90% of cases. When performing ERCP, material can be taken for cytological examination. When catheterizing the BSD and introducing a contrast agent, it is possible to detect destruction of the main passages of the main pancreatic duct, and determine the site of obstruction in jaundice. Four main types of changes in the ducts in case of a tumor are identified:

1. break;
2. stenosis;
3. "bare duct";
4. destruction of the lateral ducts with the main duct unchanged.

In approximately 3% of cases, according to various authors, the study may be accompanied by complications (even in the form of acute pancreatitis).

The pancreas is usually not accessible for visualization during laparoscopy, and the diagnosis is established based on indirect signs.

In the most difficult diagnostic situations, it is necessary to resort to diagnostic laparotomy. But even in these cases there are great difficulties: in 9% of the patients we observed, cancer of the gland was not recognized during laparotomy; similar difficulties may also be encountered by the dissector before careful dissection and analysis of the tumor mass.

An important prerequisite for successful cancer diagnostics in the future is the introduction of the serological method, i.e. the determination of the oncofetal pancreatic antigen, a-fetoprotein. Standard methods for its determination are currently already beginning to be used in large diagnostic oncological and gastroenterological institutions.

The very large number of diagnostic methods that have appeared in recent years, facilitating the detection of pancreatic cancer, sometimes puts the doctor in a difficult position. Questions arise: how to optimally draw up a diagnostic search plan, which instrumental and diagnostic methods should be used first if a tumor lesion of the pancreas is suspected, and which ones should be used later if the diagnosis remains unclear, i.e. how to determine the sequence of laboratory and instrumental examination of the patient in order to establish an accurate diagnosis in the shortest possible time and at the same time ensure the highest possible safety for the patient (considering that many invasive and radiation methods can cause certain complications in individual cases, no matter how experienced the doctor performing these studies is).

Thus, first of all, it is necessary to use non-invasive diagnostic methods. In this regard, firstly, ultrasound, then X-ray examination, CT, determination of the exocrine function of the gland deserve attention. Angiography and ERCP, laparoscopy and other invasive and rather complex to perform and unsafe for the patient methods of examination are usually performed when surgical intervention is possible or necessary and there are no serious contraindications for their use. This principle is followed by all experienced doctors, although some changes in the sequence of application of diagnostic methods may be due to the clinical features of the manifestation and course of the disease, as well as local possibilities of using certain diagnostic methods.

Differential diagnosis

Pancreatic cancer, as indicated, can proceed with an extremely diverse clinical picture, imitating various other diseases ( stomach cancer, cholelithiasis, perforated ulcer of the stomach and duodenum, lumbosacral radiculitis, viral hepatitis - icteric forms, subdiaphragmatic abscess, etc.). Therefore, diagnosis and differential diagnosis of this disease is often extremely difficult.

Most often, differential diagnostics must be performed in subhepatic jaundice between a tumor of the head of the pancreas, compressing and growing into the common bile duct, and a gallstone that has caused its obstruction. It should always be taken into account that in cholelithiasis, obstruction of the common bile duct by a stone and jaundice occur after a severe attack of biliary colic, which is not typical for pancreatic cancer. Ultrasound and CT in cancer can reveal a focus (or several foci) of compaction in the pancreas. The classic differential diagnostic sign is Courvoisier's symptom: it is usually positive in pancreatic cancer and negative in blockage of the common bile duct by a stone (since the gallbladder is usually cicatricially wrinkled due to previous long-term calculous cholecystitis ). This symptom is detected by palpation in 27.8% of patients with cancer of the head of the pancreas. Modern diagnostic methods - ultrasound, CT allow to detect or confirm an enlargement of the gallbladder in all cases of its actual enlargement (it is necessary to keep in mind that if the patient suffered from cholelithiasis with frequent exacerbations of biliary colic and cholecystitis long before the development of pancreatic cancer, his gallbladder may be shriveled due to the inflammatory-scarring process, and in case of blockage of the cystic duct by a stone, it is disconnected). These same studies allow to determine the presence of stones in the gallbladder, tumor metastases to the liver and other pathological changes.

In most cases, BSD cancer has the same main symptoms as pancreatic head cancer, but it often causes intestinal bleeding. The diagnosis is confirmed by duodenofibroscopy with targeted tumor biopsy. Obstructive jaundice can also be caused by tumor damage to the hepatic ducts, common bile duct (which is relatively rare, but should not be forgotten), or a growing tumor of the gallbladder. Jaundice can also be a consequence of an adhesive process with narrowing of the bile ducts (after cholecystectomy, gastric resection, etc.), compression of the ducts by enlarged lymph nodes in the liver hilum, etc. Therefore, using modern, fairly informative methods, it is always necessary to clarify the localization and cause of the bile outflow disorder.

Chronic inflammation of the pancreas can also cause stenosis and compression of the ducts. For differential diagnosis of the tumor, it is necessary to keep in mind that changes in the ducts of the gland are more common in chronic pancreatitis; there are cystic expansions of them; narrowing of the distal section of the common bile duct usually begins from the CBD itself.

Focal lesions of the pancreas may be caused by metastases of malignant tumors of other organs (comparatively rare, more often from the stomach), benign tumors, a cyst or several cysts of the pancreas, syphilitic gumma and some other diseases, which should also be taken into account in differential diagnostics. A thorough examination of the patient using the above-mentioned modern methods facilitates correct diagnostics.

Differential diagnostics of the icteric form of pancreatic cancer is based on the classic signs of differences between hepatic and subhepatic jaundice; in necessary cases, ultrasound of the pancreas and CT are performed; if there are any doubts, hepatitis antigens and antibodies to them are determined in the blood serum.

[ 1 ], [ 2 ], [ 3 ], [ 4 ], [ 5 ], [ 6 ]