Pancreatic cystadenocarcinoma

　　The etiology of pancreatic cystic adenocarcinoma is not yet clear. Recent large-scale studies have shown that the occurrence of pancreatic cystic adenocarcinoma may be related to the following factors:

　　1. Smoking A large number of studies support the close relationship between pancreatic cystic adenocarcinoma and smoking. Possible mechanisms by which smoking causes pancreatic cystic adenocarcinoma: smoking promotes the secretion of tumor-specific N-nitrosamines into the bile duct, which then refluxes into the pancreatic duct; the specific action of tumor-specific N-nitrosamines on organs can follow the blood into the pancreas; smoking increases blood lipid levels, triggering pancreatic cancer. Smokers may be more prone to cancer due to low cell methylation levels. The experimental study by Stolzenberg et al. has confirmed that maintaining sufficient levels of folic acid and pyridoxine can reduce the risk of pancreatic cystic adenocarcinoma related to smoking.

　　2. Drinking The incidence of pancreatic cystic adenocarcinoma also varies among different races after drinking.

　　3. Diabetes Experimental studies have shown that insulin can promote the growth of pancreatic cystic adenocarcinoma cells in vitro or in vivo.

　　4. Chronic pancreatitis Epidemiological and molecular epidemiological studies mostly support the possibility that chronic pancreatitis can develop into pancreatic cystic adenocarcinoma. Friess's research has proven the existence of certain connections between chronic pancreatitis and pancreatic cystic adenocarcinoma at the molecular level.

　　5. Helicobacter pylori (Hp) Studies have shown that there are Hp serum positive results in patients with pancreatic cystic adenocarcinoma, and there is a significant difference compared with the control group, suggesting that Hp infection is related to pancreatic cystic adenocarcinoma.

　　6. Non-steroidal anti-inflammatory drugs (NSAIDs) Some studies have shown that the incidence of pancreatic cystic adenocarcinoma is reduced in women taking aspirin, but some studies have also shown that regular use of aspirin does not reduce the incidence of pancreatic cystic adenocarcinoma, and the risk of developing pancreatic cystic adenocarcinoma may increase.

　　7. A survey found that coffee can increase the risk of pancreatic cystic adenocarcinoma by 4 times. Studies have shown that coffee can inhibit DNA repair and induce the mitotic process before DNA replication is completed, which is the main cause of its carcinogenicity.

　　It may be complicated by symptoms such as biliary tract obstruction, duodenal obstruction, etc. Obstruction of the splenic vein by the tumor can cause splenomegaly and localized portal hypertension, leading to gastric bleeding or esophageal varices.

　　1. Weight loss:Weight loss caused by pancreatic cystic adenocarcinoma is most prominent, with significant weight loss occurring in the short term after onset, which may reach more than 30 jin, accompanied by weakness and fatigue.

　　2. Symptomatic diabetes:A small number of patients may initially present with symptoms of diabetes. Therefore, if diabetic patients experience persistent abdominal pain, or elderly people suddenly develop diabetes, or if they have diabetes and their condition suddenly worsens recently, they should be alert to the possibility of pancreatic cancer.

　　3. Thrombophlebitis:Late-stage pancreatic cystic adenocarcinoma patients may develop migratory thrombophlebitis or arterial thrombosis.

　　4. Mental symptoms:Some patients with pancreatic cystic adenocarcinoma may show mental symptoms such as anxiety, impatience, depression, and personality changes.

　　1. The main symptoms of pancreatic cystadenocarcinoma are hidden pain in the upper and middle abdomen or back pain, and an abdominal mass in the upper abdomen. Abdominal pain is not usually severe, and some patients may only have a feeling of fullness or discomfort. Other symptoms may include decreased appetite, nausea, indigestion, weight loss, jaundice, etc. A few patients may experience gastrointestinal bleeding; some patients may have no complaints at all in their daily life, and the disease is unexpectedly found during laparotomy or post-mortem examination.

　　2. The abdominal mass is similar in size, the small ones can just be felt in the upper abdomen, and the large ones can fill the entire abdominal cavity, even extending into the pelvic cavity. The abdominal mass is generally not painful and can present with a cystic or firm feeling. When secondary intracystic hemorrhage occurs, the abdominal mass can suddenly increase in size, the pain can be exacerbated, and the tenderness is obvious. Chinese Li Chuanshan et al. reported 6 cases of pancreatic cystic tumors, all of which were diagnosed due to an upper abdominal mass and abdominal pain or back pain. Among them, 3 cases with intolerable back pain were cystadenocarcinoma. When the tumor infiltrates or compresses the common bile duct, obstructive jaundice may occur.

　　3. Due to the lack of specificity of the symptoms and signs of pancreatic cystadenocarcinoma, especially at the stage of small mass, it often causes difficulties in clinical diagnosis, making many patients have symptoms for several months or even several years when they seek medical attention, even up to 15 years. Becker et al. reported that the time of symptom onset before the final diagnosis of pancreatic cystadenocarcinoma was 7 months to 11 years, with an average of 22 months.

　　Mainly for etiological prevention, quitting smoking and controlling alcohol consumption, reducing coffee intake, and eating more fresh vegetables and fruits can effectively prevent the occurrence or reduce the incidence of pancreatic cystadenocarcinoma. Although certain progress has been made in the imaging diagnostic technology and molecular biological detection methods for pancreatic cancer in recent years, the problem of early diagnosis is far from being solved. 85% of the patients seek medical attention when they are already in the late stage. Among the cases diagnosed clinically, only 10% to 15% of the patients have the opportunity for surgical resection, among whom only 5% to 7.5% can be cured. Therefore, the treatment of advanced pancreatic cancer is a realistic problem that must be faced in clinical work. According to the survey statistics of the United States, the overall surgical resection rate and 5-year survival rate of pancreatic cancer have not changed significantly in the past 20 years. Faced with such a severe reality, it has to be admitted that today, in the 21st century, medical workers still face huge challenges in the diagnosis and treatment of pancreatic cancer. How to improve the early diagnosis rate of pancreatic cancer under the existing conditions, strengthen comprehensive treatment, and improve the prognosis requires us to pay more attention and make further efforts.

　　1. Laboratory examination

　　If the patient's urine sugar and blood sugar levels are elevated, and the glucose tolerance is decreased, it helps to establish the value of pancreatic lesions. In the 62 cases of pancreatic cystadenocarcinoma reported by Strodel, 11% of the patients had diabetes.

　　2. X-ray examination

　　On the abdominal plain film, calcification shadows of the cyst wall can be seen, with a shape of circular or crescent-shaped. Warshaw reported 67 cases of pancreatic cyst patients, among whom 7 cases with calcification shadows were pancreatic cystadenocarcinoma, while patients with pseudocyst, retention cyst, and cystadenoma had few calcification foci.

　　Upper gastrointestinal barium meal examination generally has no specific diagnostic value, but if there is an expansion of the duodenal ring, or displacement of the stomach or transverse colon, it can help to guess the location and size of the mass.

　　Venous pyelography has no specific diagnostic value, and through the displacement direction and compression degree of the left kidney, the location, size, and growth direction of the mass can be understood.

　　3. B-ultrasound examination

　　It can show the location, size, and relationship between the tumor and surrounding organs, and help to clarify the structure and morphological characteristics of the pancreas mass, such as the nature of the cystic, solid, size and number of cystic cavities, contents of the cyst, cyst wall and septum, etc., providing an important basis for diagnosis and differential diagnosis.

　　4. Abdominal CT

　　It can clearly show the location, size, and relationship between the abdominal mass and surrounding organs; CT can show the cyst as solitary or multilocular, the latter is often a reliable sign of pancreatic cystadenoma or cystadenocarcinoma; CT can also suggest the presence of liver or peritoneal lymph node metastasis of the tumor, and if there is a metastatic focus, it supports the diagnosis of pancreatic cystadenocarcinoma.

　　5. Selective abdominal aortic or superior mesenteric artery angiography

　　It can determine the shape, size, and location of the tumor. Due to the relatively rich blood supply of pancreatic cystic cavity cancer, it can be distinguished from the avascular pseudocysts of the pancreas and the less vascular pancreatic cancer. The main signs of angiography of pancreatic cystadenoma are: compression, displacement, torsion, stretching, and irregularity around the large blood vessels in the lesion area; rich blood supply, congestion in the tumor area, manifested as stasis of contrast agent in the capillaries; some blood vessels are embedded in the tumor tissue and are infiltrated by the lesion, suggesting the possibility of malignancy; arteriovenous shunting; venous return obstruction; the absence of blood vessels or low vascularization in the lesion area, which cannot completely exclude cystadenoma. Warshaw et al. performed angiography examinations on 11 patients with pancreatic cystic cavity cancer, only 2 had rich blood supply, and 4 of the 10 patients with cystadenoma had rich blood supply; in addition, the angiography of 19 cystadenomas was all of low blood supply.

　　6. Retrograde Cholangiopancreatography (ERCP) Examination

　　When diagnosis is difficult, the application of ERCP examination helps to exclude chronic pancreatitis, pseudocysts of the pancreas, and intraductal cancer, but it is not very helpful in distinguishing between cystadenocarcinoma and cystadenoma. About 70% of patients with pseudocysts of the pancreas have communication between the pancreatic duct and the cyst; pancreatic cancer can manifest as narrowing or obstruction of the pancreatic duct, with Warshaw et al. reporting that 50% of patients with pancreatic cystadenocarcinoma have normal pancreatic duct angiography images, and 33% of patients have the main pancreatic duct bending into an arch shape around the tumor.

　　Mucinous ductal ectasia (mucinous ductal ectasia) is a recently recognized precancerous lesion, when papillary hyperplasia appears in the pancreatic duct and produces a large amount of mucus, due to the filling of the main pancreatic duct with mucus, it can induce obstructive pancreatitis. This damage involves part or all of the pancreas, and further progression of the lesion can lead to interductal ectasia. During retrograde pancreatic duct cannulation, one can see mucus flowing out at the opening of the pancreatic duct, and these enlarged and dilated pancreatic ducts can be displayed on the retrograde pancreatic duct造影 films.

　　7. Percutaneous fine needle aspiration of pancreatic cysts for fluid extraction examination

　　Percutaneous fine needle aspiration of pancreatic cysts for fluid extraction to determine amylase, carcinoembryonic antigen, CA19-9, and perform cytological examination can help distinguish the nature of the cyst. During aspiration, imaging, B-ultrasound, and CT guidance can be used, and it can also be performed directly during surgery. The amylase content in the fluid of pancreatic pseudocysts and retention cysts is extremely high, while the amylase in cystic tumors is often not elevated. The carcinoembryonic antigen value in the fluid of mucinous pancreatic cysts (cystadenoma or cystadenocarcinoma) is significantly higher than that in pseudocysts and serous cysts. Ferrer reported a case of pancreatic cystadenocarcinoma, where the plasma carcinoembryonic antigen was 200 μg/ml during laparotomy, and it dropped to normal after tumor resection. The carcinoembryonic antigen in the cyst fluid was 100,000 times higher than the normal plasma level. Since carcinoembryonic antigen originates from columnar epithelium that can secrete mucus, both cystadenoma and cystadenocarcinoma can produce a large amount of carcinoembryonic antigen, so it is of little help in distinguishing benign and malignant diseases.

　　Recently, Rubin reported that measuring the CA15-3 protein expression in the contents of cysts can distinguish benign and malignant pancreatic mucinous cystic tumors. CA15-3 is a mucin protein over 400 KDa, which exists in the membrane of milk fat globules and multiple adenocarcinomas including the pancreas. The author obtained the intracystic fluid of the pancreatic cyst through percutaneous needle aspiration and determined the concentration of CA15-3 using the monoclonal antibody 115-D8 and DF-3 radioimmunoassay. The normal value is 0-30 IU/ml; the CA15-3 value in the fluid of 6 cases of pancreatic cystadenocarcinoma is 40-392 IU/ml; the average value of 3 cases of mucinous cystadenoma is 4.7 IU/ml (0-14 IU/ml), the average value of 5 cases of serous cystadenoma is 9.2 IU/ml (0-32 IU/ml), and the average value of 6 cases of pseudocyst is 15.3 IU/ml (0-66 IU/ml). The average CA15-3 value of the last three groups of benign pancreatic cystic lesions is 10.6 IU/ml, which is significantly lower than the average CA15-3 value of pancreatic cystadenocarcinoma. The sensitivity of measuring CA15-3 in the cyst fluid to distinguish benign and malignant pancreatic cystic lesions is 100%, and the specificity also reaches 100% (P<0.01).

　　1. What kind of food is good for the body after the surgery for pancreatic cystadenocarcinoma

　　Diet should first be chosen to be rich in nutrition, easy to digest, low in刺激性, and low in fat. It can provide high-protein, high-carbohydrate foods such as dairy products, fish and meat, liver, egg white, refined flour products, lotus root powder, fruit juice, vegetable soup, sticky rice, and so on. It should be combined with foods that have the effect of softening hard masses, dispersing phlegm, and regulating the liver and Qi, such as hawthorn, malt, Job's tears, magic powder, red beans, shepherd's purse, ophiopogon, costus, melon, angelica, astragalus, codonopsis, honeysuckle, kelp, seaweed, and nori. It is recommended to commonly use crystals that tonify Qi and blood, strengthen the spleen and harmonize the stomach, such as glutinous rice, red beans, broad beans, yam, goji, dulse, figs, hazelnuts, milk, and chestnut flour, etc.

　　2. What foods should be avoided after the surgery for pancreatic cystadenocarcinoma

　　It is necessary to avoid excessive drinking, overeating, alcoholism, and high-fat diet. It is advisable to eat less or limit the intake of foods that are difficult to digest, such as fatty meat, fish roe, brain, greasy, fried foods, and avoid spicy and刺激性 foods such as scallions, ginger, garlic, and chili peppers. It is also necessary to avoid smoking and drinking.

　　1. Surgical resection of pancreatic cystadenocarcinoma, including part of the normal pancreas in the location of the tumor, is the only effective method for the treatment of this disease. Since most pancreatic cystadenocarcinomas have light adhesions, even with obvious adhesions, they are easy to separate. Therefore, except for cases where the tumor has widely metastasized, the overall condition is extremely poor, important organs are involved, and other situations, it is generally advisable to strive for radical resection. Different surgical methods such as simple cystectomy, pancreas tail and spleen resection, pancreatoduodenectomy, or total pancreatectomy can be selected according to the location and extent of the lesion, the relationship between the tumor and adjacent organs, and the degree of metastasis and infiltration. It is necessary to keep the cyst intact as much as possible during the operation. Once the cyst wall ruptures, it will lead to seeding metastasis in the peritoneal cavity.

　　2. In the treatment process of pancreatic cystadenocarcinoma, common mistakes include: overestimating the difficulty of surgical resection of the tumor, which causes some tumors that can be completely resected with effort to be only palliative or resected or cyst drainage. Diagnosing pancreatic pseudocyst, retention cyst, and cystadenoma is done easily based on a small amount of frozen section examination of cyst tissue during surgery, and cysto-external drainage procedures are performed accordingly. There are cases of pancreatic pseudocyst or cystadenoma developing into cystadenocarcinoma after incomplete resection or drainage in literature and data both in China and abroad. It cannot be ruled out that some patients may have cancer at the initial surgery but were not discovered. Therefore, for pancreatic cystic masses with an uncertain nature, especially mucinous cysts, treatment should be handled according to the principles of pancreatic cystadenocarcinoma, resecting the mass and part of the pancreatic tissue in the location. For pancreatic cystadenocarcinoma, it is absolutely not advisable to perform cysto-internal or external drainage, otherwise, it not only fails to achieve the purpose of surgical treatment but also increases the opportunity of cyst infection, delaying the opportunity for radical surgery.

　　3. Pancreatic cystadenocarcinoma is insensitive to chemotherapy and radiotherapy.