Duodenal adenocarcinoma

　　First, etiology

　　Currently, the etiology of duodenal adenocarcinoma is not well understood. Certain substances secreted by bile and pancreatic juice, such as lithocholic acid, etc., secondary bile acids, may be carcinogens that promote tumor formation. Diseases such as familial polyposis, Gardner and Turcot syndromes, von Recklinghausen syndrome, Lynch syndrome, and benign epithelial tumors such as villous adenomas may be related to the occurrence of duodenal adenocarcinoma. There are also reports that duodenal ulcer or diverticulum malignancy and genetic factors are also related to duodenal adenocarcinoma.

　　Second, pathogenesis

　　1, Common sitesDuodenal adenocarcinoma mostly occurs around the papilla of the descending part, accounting for about 60%, followed by the infravesical segment, and the bulb is the least common.

　　2, Pathological morphology

　　(1) Gross morphology: The gross morphology of duodenal adenocarcinoma can be divided into polypoid, ulcerative, annular ulcerative, and diffuse infiltration types. Among them, the polypoid type is the most common, accounting for about 60%, followed by the ulcerative type.

　　(2) Histological morphology: Under the microscope, duodenal adenocarcinoma mostly belongs to papillary adenocarcinoma or tubular adenocarcinoma, with most papillary adenocarcinoma polyps located near the duodenal papilla. Other parts are mostly tubular adenocarcinoma, presenting as ulcerative or annular ulcerative, with the ulcer lesions extending horizontally causing duodenal annular stricture.

　　Complications of duodenal adenocarcinoma surgery include sepsis, bile fistula or pancreatic fistula, and hemorrhage. The mortality rate fluctuates between 27% and 46%. The occurrence of sepsis is often due to blood stasis or leakage from the gastrointestinal tract, and many cases adopt an invasive treatment method such as percutaneous puncture drainage. 10% to 18% of patients develop pancreatic fistula, with symptoms similar to sepsis, and 7% to 10% mortality is related to pancreatic fistula. Hemorrhage occurring immediately after surgery is usually due to poorly tied blood vessels or blood clots within the vessels that were not discovered. Delayed hemorrhage may be due to necrosis of arteries or detachment of ligatures caused by sepsis or fistula formation. Delayed gastric emptying after pancreatic resection, especially after pylorus-preserving surgery, is a relatively common non-life-threatening complication but may trigger local peritonitis. Less common complications include intestinal obstruction, mesenteric thrombosis, liver failure, cholangitis, pancreatitis, renal failure, and necrotizing fasciitis.

　　First, clinical symptoms and signs

　　Early symptoms are generally not obvious, or only discomfort, pain, weakness, anemia, etc., and the symptoms and signs are related to the early or late stage of the disease and the location of the tumor. According to literature statistics, the common symptoms and signs are listed as follows:

　　1, Pain:They are mostly similar to ulcer disease, manifested as discomfort or dull pain in the upper abdomen, the pain does not subside after eating, and sometimes the pain can radiate to the back.

　　2, Loss of appetite, nausea, vomiting:This type of non-specific gastrointestinal symptom occurs in 30% to 40% of duodenal adenocarcinoma cases. If vomiting frequently and the content is large, it is mostly due to the gradual enlargement of the tumor blocking the intestinal lumen, causing partial or complete obstruction of the duodenum. Whether the vomiting content contains bile can determine the site of obstruction.

　　3, Anemia, hemorrhage:It is the most common symptom, and its bleeding is mainly manifested as chronic hemorrhage, such as occult blood in feces, black stools; large amounts of hemorrhage can cause vomiting.

　　4, Jaundice:It is caused by the tumor blocking the ampulla. This type of tumor often causes jaundice due to tumor necrosis and shedding, causing jaundice to fluctuate. It is common for jaundice to follow positive fecal occult blood test and the jaundice also subsides. In addition, jaundice is often accompanied by abdominal pain, which is different from the painless, progressive, and severe jaundice commonly seen in pancreatic head cancer.

　　5, Weight loss:This symptom is also relatively common, but progressive weight loss often indicates poor treatment effect.

　　6, Abdominal mass:When the tumor grows larger or invades surrounding tissues, some cases can palpate a mass in the upper right abdomen.

　　Second, clinical staging

　　China has not yet conducted detailed staging for duodenal adenocarcinoma, and its staging methods are mostly based on the staging method formulated by the American Cancer Society.

　　1, Clinical staging:The first stage, the tumor is limited to the duodenal wall; the second stage, the tumor has penetrated the duodenal wall; the third stage, the tumor has regional lymph node metastasis; the fourth stage, the tumor has distant metastasis.

　　2, The TNM staging is

　　T:Primary tumor.

　　To:No evidence of primary tumor.

　　Tis:In situ carcinoma.

　　T1:Tumor invades the lamina propria or submucosa.

　　T2:Tumor invades the muscular layer.

　　T3:Tumor penetrates the muscular layer and infiltrates the serous membrane or penetrates the muscular layer without peritoneal covering (such as mesentery or retroperitoneum) and infiltrates outward ≤2cm.

　　T4:Tumor invasion of adjacent organs and structures, including the pancreas.

　　N:Local lymph nodes.

　　N0:No local lymph node metastasis.

　　N1:Local lymph node metastasis.

　　M:Distant metastasis.

　　Mo:No distant metastasis.

　　ML:There is distant metastasis.

　　1, Eat less or avoid foods rich in saturated fats and cholesterol, including: lard, butter, fatty meat, animal internal organs, fish roe, etc.

　　2, Vegetable oils should be limited to about 20 to 30 grams per person per day (approximately 2 to 3 tablespoons).

　　2. Do not eat or eat less fried foods.

　　3. Eat foods rich in unsaturated fatty acids, such as olive oil, tuna, etc.

　　4. Supplement dietary fiber with more than 35 grams per day.

　　5. Eat more foods rich in dietary fiber: konjac, soybeans and their products, fresh vegetables and fruits, algae, etc.

　　6. Use some coarse grains to replace fine grains.

　　7. Eat more fresh vegetables and fruits to supplement carotene and vitamin C.

　　8. You can eat some things with antitumor effects and enhance immunity, such as: American giant termite.

　　10. Eat nuts, peanuts, dairy products, seafood, etc. in moderation to supplement vitamin E.

　　11. Pay attention to consume foods rich in trace elements selenium such as malt, fish, mushrooms, etc.

　　First, laboratory examination

　　1. Tumor mucin detection

　　It can suggest the source of the tumor tissue. Ampullary cancer can originate from the mucosa of the duodenal wall, pancreatic duct, or bile duct, and the prognosis may be different due to the different source sites. Therefore, Dauson and Connolly analyze the mucin produced by the tumor to suggest the source of the tumor tissue: salivary mucin comes from the true ampulla tumor is the characteristic of bile duct epithelium and duodenal mucosa; neutral mucin is the characteristic secretory protein of Bruner gland; and sulfuric mucin is mainly produced by the pancreatic duct.

　　2. Histopathological examination

　　Tumors can manifest as polypoid, infiltrative, and ulcerative types. Polypoid masses are soft in texture, large ones are cauliflower-like, and may come from adenomatous polyps or villous adenomas that have undergone malignant transformation. The tumor margin is elevated like a dike and is harder. When the tumor grows infiltratively, it can block the duodenal lumen, causing narrowing and obstruction of the duodenal lumen. Microscopic examination shows that duodenal cancer is mainly adenocarcinoma, accounting for 81.4%, a small number of cancer cells produce a large amount of mucus to form mucinous adenocarcinoma, and occasionally poorly differentiated undifferentiated cancer can be seen.

　　3. Fecal occult blood test

　　When the ulcerative lesion is the main, occult blood in stool can be positive.

　　Second, imaging examination

　　1. Gas-barium double contrast imaging

　　It is the preferred examination method. If gas-barium double contrast imaging is performed, it can improve the diagnostic rate. Because the morphology of the tumor is different, its X-ray image has different characteristics. Generally, part of the mucosa is rough and disordered or rugae disappear, the intestinal wall is rigid, and polypoid filling defects, ulcers, duodenal cavity narrowing, and abdominal deformation caused by ampulla of Vater adenocarcinoma and ulcer are also visible. It is easy to misdiagnose.

　　2. Duodenal fiberoptic endoscopy

　　Under the microscope, the mucosa of the lesion site is ulcerated, and necrotic tissue is attached to the surface. If the mucosa at the top of the adenoma is rough and eroded, consider malignancy. For suspicious areas, multiple tissue samples should be taken for pathological examination to avoid misdiagnosis. Because fiberoptic endoscopy is difficult to see the third and fourth segments, there may be missed diagnosis, and clinical hyperlong endoscopy or barium meal can be used to make up for its shortcomings.

　　3. Ultrasound

　　Endoscopic ultrasound and CT examination: visible local thickening of the intestinal wall, and can understand the range and depth of tumor infiltration, whether there is metastasis of regional lymph nodes around, and the condition of abdominal visceral organs such as the liver.

　　1. Reduce the intake of fats in the diet.

　　2. Avoid spicy and irritating foods, and quit smoking and drinking.

　　3. Increase dietary fiber intake: The main function of fiber in food is to better maintain intestinal motility, keep bowel movements smooth, and reduce bacterial growth.

　　4. Maintain a pleasant mood and appropriate, relaxed outdoor activities.

　　5. Fresh fruits and vegetables, high-quality protein, and light flavors are recommended. Green, yellow, lemon, asparagus, almond milk, water chestnut, jujube, garlic, red vegetables, and black fungus are anticancer substances that can block the generation of cancer cells.

　　1. Treatment

　　Duodenal adenocarcinoma should be treated with radical resection in principle. The surgical procedure can be selected according to the location and stage of the cancer, such as duodenal segmental resection or pancreaticoduodenectomy. For inoperable tumors, palliative bile-enteric or gastrointestinal drainage can be used. According to literature reports, after the 1990s, the rate of pancreaticoduodenectomy for duodenal adenocarcinoma increased to 62% to 90%, and the 5-year survival rate after surgery reached 25% to 60%. Due to the compliance of pancreaticoduodenectomy with the principles of tumor surgical treatment, en bloc resection, and lymph node clearance, as well as its good therapeutic effect, it has been basically recognized as the standard surgical procedure for duodenal cancer. The following are the introduction of several commonly used surgical procedures and precautions:

　　1. Pancreaticoduodenectomy:During duodenal adenocarcinoma surgery, the rate of lymph node metastasis is 50% to 65%. Although many authors believe that positive lymph nodes do not affect postoperative survival rate, the pancreaticoduodenectomy is highly recommended due to its ability to extensively clear regional lymph nodes. With the improvement of surgical skills and the enhancement of perioperative management, the postoperative mortality of pancreaticoduodenectomy has decreased to below 10%. Pancreaticoduodenectomy includes two basic procedures: pylorus-preserving and pylorus-sparing. They should be selected according to the location and growth of the tumor. However, it should be noted that the incidence of complications after pancreaticoduodenectomy for duodenal adenocarcinoma is higher than that for pancreatic or biliary tract lesions, such as pancreatic leakage, which may be related to the normal consistency of the soft pancreas and the patency of the pancreatic duct. It is generally believed that attention should be paid to the following points when performing pancreaticoduodenectomy for primary duodenal cancer:

　　(1) It is better to use the sleeve-type (Child) method for pancreatic and jejunal end-to-end anastomosis, especially for those with non-dilated pancreatic ducts.

　　(2) There is a low chance of duodenal tumors involving the pancreatic hook. Therefore, when dealing with the hook, residual thin slices of pancreatic tissue adhering to the portal vein can be left under the principle of not affecting radical resection. It is more beneficial for surgical operation. In addition, when separating the fine blood vessels between the hook and the portal vein and superior mesenteric vein, they should not be pulled too hard to avoid tearing the vessels or pulling the superior mesenteric artery into the surgical field and causing injury. The blood vessels on the side of portal vein retention need to be ligated firmly, and suture ligation is more appropriate.

　　(3) In patients without obstructive jaundice, the bile duct and pancreatic duct usually do not dilate. Therefore, by placing a thin T-tube into the bile duct for drainage, one end of its horizontal arm can be placed into the distal ileum via the bile-enteric anastomosis, and the other end can be placed in the proximal bile duct, which helps to reduce the incidence of bile-enteric and pancreatic-enteric fistula.

　　(4) For patients with malnutrition, anemia, and hypoproteinemia, in addition to considering short-term TPN treatment, it is advisable to place a feeding tube in the jejunum during surgery (through the nose or through a jejunostomy tube) for postoperative enteral nutrition. Infusion of nutritional fluids and/or recovered digestive fluids such as bile and pancreatic juices is very helpful for the recovery of postoperative patients.

　　(5) For elderly patients or those with respiratory system diseases, gastrostomy should be performed.

　　(6) Postoperative prevention and treatment of respiratory system complications should be strengthened, especially pneumonia and atelectasis, by using effective antibiotics, encouraging coughing and bed activities, and other measures.

　　2. Segmental duodenectomy:This surgical method is appropriate and can achieve the goal of radical resection, with a 5-year survival rate not lower than that of pancreaticoduodenectomy. It has small incisions, fewer complications, and a low mortality rate. This method is mainly suitable for early-stage cancer in the horizontal and ascending parts, and careful exploration before and during the operation is necessary to ensure that there is no invasion of the serosal layer of the intestinal wall, no involvement of the pancreas, and no metastasis of regional lymph nodes. The lateral margin of the duodenum is fully freed, the duodenal suspensory ligament is cut, and the horizontal and ascending parts of the duodenum are freed. The duodenal segment including the tumor and the lymphatic drainage area are resected, and the distal end of the jejunum is pulled to the right behind the superior mesenteric artery and anastomosed end-to-end with the descending part of the duodenum. If the resection is extensive and it is not possible to anastomose the duodenum end-to-end, a Roux-en-Y jejuno-jejunal anastomosis can also be performed.

　　3. Local resection of papillary tumor:For elderly patients with papillary tumors or those with poor general condition who are not suitable for pancreaticoduodenectomy, local resection of the papillary tumor can be performed.

　　(1) The lower segment of the common bile duct is longitudinally incised, explored, and the location of the papilla and tumor is clarified. A probe is sent through the common bile duct incision to the papillary region, pressing against the anterior wall of the duodenum to mark, and a 5 cm long longitudinal incision is made 1 cm above it, or a transverse incision can also be made, further identifying the relationship between the papilla and the tumor within the lumen.

　　(2) Above the papillary tumor on the posterior wall of the duodenum, the position of the common bile duct can be seen. Under the support of the traction line, the posterior wall of the duodenum and the anterior wall of the common bile duct are incised about 1 cm from the tumor, and the proximal cut ends of both are sutured with fine silk thread, and the distal cut ends are also sutured to traction the papillary tumor. Using the same method, the posterior wall of the duodenum and the common bile duct are incised and sutured around the tumor 1 cm away, until the tumor is completely removed. The pancreatic duct opening is visible in the 12-3 o'clock direction, and it is sutured separately with the common bile duct and the posterior wall of the duodenum. During the tumor resection process, minor bleeding points can be ligated or stopped by electrocoagulation. After the tumor is removed, the wound needs to be thoroughly hemostatised.

　　(3) A suitable, 4-5 cm long thin silicone tube is placed through the duodenopancreatic anastomosis, inserted into the pancreatic duct to support the anastomosis, and sutured to the pancreatic duct with absorbable sutures to fix it in place. A T-tube is placed through the common bile duct incision, with one end inserted into the proximal bile duct and the other extending through the duodenopancreatic anastomosis into the duodenal lumen, serving as a support. The anterior wall incision of the duodenum and the common bile duct incision are sutured in a transverse manner, with the T-tube exiting from the latter.

　　(4) Remove the gallbladder, place an abdominal drain, and close the abdomen.

　　(5) Local resection of papillary tumors not only requires complete resection of the tumor but also requires no residual tumor tissue at the margin. Frozen section examination should be performed to assist in diagnosis.

　　(6) After completing the anastomosis of the bile duct, pancreatic duct, and posterior wall of the duodenum, if a T-tube has been placed, there is no need to perform a side-to-side anastomosis of the bile duct and duodenum. However, the T-tube should be retained for more than 3 to 6 months.

　　(7) Strengthen the prevention of complications such as pancreatic fistula, bile fistula, pancreatitis, and hemorrhage after surgery. Use somatostatin, H2 receptor blockers, and other drugs. The author once had a case of duodenal papillary adenocarcinoma that recurred locally after 3 years of local resection, and the patient survived for nearly 5 years after the second local resection.

　　4. Partial Gastrectomy:For early-stage cancer of the duodenal bulb, if the lesion is close to the pylorus, this operation can be used. Note that the margin must be more than 2 cm away from the tumor, and surrounding important structures should not be injured.

　　Radiation therapy and chemotherapy have no significant effect on duodenal adenocarcinoma. Some reports indicate that chemotherapy can prolong survival time and can be used in combination with surgery or after surgery.

　　Second, prognosis

　　The overall prognosis of duodenal adenocarcinoma is better than that of pancreatic head cancer and distal bile duct cancer. The resection rate is over 70%, and the 5-year survival rate after radical resection is 25% to 60%. However, the prognosis of unresectable duodenal cancer is poor, with an average survival time of 4 to 6 months, and almost no long-term survival cases. Moreover, the prognosis of duodenal cancer also varies with the site of occurrence. It is generally believed that the prognosis of adenocarcinoma occurring in the 3rd and 4th segments of the duodenum is better than that occurring in the 1st and 2nd segments, and the reasons are considered to be as follows: 3 points:

　　1. The biological characteristics are different. The biological characteristics of the 3rd and 4th segment tumors show mesenteric characteristics, while the 1st and 2nd segment tumors show foregut characteristics.

　　2. The clinical findings of the 3rd and 4th segment tumors are often relatively early, even though the tumor has broken through the固有muscle layer, it often does not invade surrounding organs but only invades surrounding fatty tissue.

　　3. The surgery mortality rate of the 3rd and 4th segment adenocarcinoma is low due to the possibility of intestinal segment resection. Many data show that the prognosis of duodenal adenocarcinoma is not related to the presence or absence of lymph node positivity, the depth of tumor infiltration, the degree of histological differentiation, and gender, etc. However, invasion by the pancreas and other organs is considered to be a cause of local recurrence and mortality.