Hepatic duct cancer generally refers to extrahepatic cholangiocarcinoma. Since the clinical manifestations and treatment methods of distal common bile duct cancer or ampullary cancer are essentially the same as those of pancreatic head cancer, they are often classified as periampullary cancer.

bubble_chart Epidemiology

The incidence of cholangiocarcinoma is lower than that of gallbladder cancer, accounting for approximately 30–40% of malignant tumors in the biliary system. Autopsy data indicate that the occurrence rate of cholangiocarcinoma ranges from 0.01% to 0.46%. However, in recent years, the incidence of cholangiocarcinoma appears to be increasing, possibly due to improved diagnostic methods leading to higher detection rates. At Zhongshan Hospital, the number of cholangiocarcinoma cases treated in the 1950s and 1960s was 11 and 18, respectively, while in the 1970s, the number rose to 46. Similar trends have been reported internationally. Most cases of cholangiocarcinoma occur in individuals aged 50–70, though cases as young as 20 have also been documented. The disease is more common in men, with a male-to-female ratio of approximately 2–2.5:1.

bubble_chart Etiology

The cause of cholangiocarcinoma is unknown. Gallstones, bile duct infections, or bile stasis do not appear to be related to the occurrence of cholangiocarcinoma. Only about 25% of cholangiocarcinoma patients have accompanying bile duct stones. Some suggest that individuals with the following conditions are more prone to developing cholangiocarcinoma: chronic ulcerative colitis, congenital hepatic fibrosis, and liver fluke infections (Clonorchis sinensis). Reports indicate that 9% of chronic ulcerative colitis patients also have cholangiocarcinoma. The relationship between primary sclerosing cholangitis and cholangiocarcinoma remains inconclusive. Some authors argue that primary sclerosing cholangitis does not exist at all, and that long-term follow-up or multiple intraoperative biopsies ultimately confirm malignancy. They propose that primary sclerosing cholangitis is essentially a slow-growing form of cholangiocarcinoma. Patients with congenital choledochal cysts have a higher risk of developing cancer in the cyst or surrounding bile ducts, with rates as high as 17.5%. If a cyst-enterostomy is performed, the incidence of cancer within the cyst can exceed 80%.

Most cholangiocarcinomas are well-differentiated adenocarcinomas, with undifferentiated carcinoma and papillary carcinoma being rare, and squamous cell carcinoma and fleshy tumor even rarer. The gross morphology of cholangiocarcinoma can be divided into three types: ① Papillary, the least common type, often multifocal; ② Nodular, also uncommon but slightly more frequent than papillary carcinoma, usually solitary; ③ Diffuse, the most common, accounting for about two-thirds of all cholangiocarcinomas. The bile duct wall shows extensive thickening with surrounding tissue fibrosis. These tumors often spread submucosally, with extensive local infiltration but less frequent distant metastasis. Most tumors grow slowly, though a few grow rapidly and may metastasize early, potentially involving the entire extrahepatic bile duct.

Cholangiocarcinomas can be classified based on their location in the bile duct. The most commonly used classification is that proposed by Longmire, dividing them into upper-third, middle-third, and lower-third cholangiocarcinomas. Upper-third cholangiocarcinoma refers to tumors located at the confluence of the common hepatic duct and the left/right hepatic ducts or their proximal segments, also known as Klatskin tumors. These exhibit cellular atypia, papillary ductal wall infiltration, and perineural invasion. Middle-third cholangiocarcinoma refers to tumors located in the common bile duct from the cystic duct to the lower border of the duodenum. Lower-third cholangiocarcinoma refers to tumors located in the common bile duct below the lower border of the duodenum. Upper-third cholangiocarcinoma is the most common, with an incidence of 20.9–76%. Among 50 cases of cholangiocarcinoma treated at Zhongshan Hospital, 31 were located at the hepatic duct confluence or higher, accounting for 62%.

It occurs more frequently in men over 60 years old with sexually transmitted diseases, primarily presenting as progressively deepening jaundice accompanied by cutaneous pruritus. About half of the patients have a history of mild mid-upper abdominal pain or fever, though a few may exhibit manifestations of acute cholangitis. Approximately half of the patients experience loss of appetite and weight loss. Whether the gallbladder is enlarged depends on the location of the bile duct cancer. If the bile duct cancer is located proximal to the junction of the gallbladder and the common hepatic duct, the gallbladder will not be enlarged. The liver is often enlarged and can be palpated below the ribs or xiphoid process, with a firm texture and minimal tenderness. Laboratory tests reveal obstructive jaundice, with elevated blood bilirubin and alkaline phosphatase levels.

bubble_chart Diagnosis

Since the application of "B" ultrasound and percutaneous transhepatic cholangiography (PTC), it has become possible to diagnose bile duct cancer before surgery. However, "B" ultrasound can generally only distinguish whether jaundice is caused by extrahepatic or intrahepatic obstruction and cannot clearly reveal the nature of the lesion. Therefore, when extrahepatic obstruction is detected and it is not due to stones, PTC should be performed to confirm the diagnosis. PTC is the primary method for diagnosing bile duct cancer, with a diagnostic accuracy rate of 94–100%. If PTC fails, endoscopic retrograde cholangiopancreatography (ERCP) can be performed to determine the location and extent of the tumor. However, in cases of complete obstruction, ERCP cannot assess the extent of proximal tumor infiltration, which is its limitation. Merely diagnosing bile duct cancer is insufficient; it is also necessary to understand the extent of the tumor and its infiltration into adjacent tissues to preliminarily determine whether the tumor can be resected or to formulate other surgical plans before surgery. Angiography, including selective hepatic artery angiography, splenoportography, and percutaneous transhepatic portography, can better assess the resectability of bile duct cancer. However, it cannot evaluate lymph node metastasis or whether the caudate lobe of the liver is involved. Computed tomography (CT) can help determine whether the tumor has invaded the liver parenchyma. If the above examinations still cannot provide a clear diagnosis, surgical exploration remains the last resort. However, difficulties may still arise. First, because the tumor often grows insidiously along the bile duct wall, obtaining suitable biopsy samples can be challenging. Microscopic examination of the biopsy often reveals clusters of cancer cells encased in dense fibrous tissue. Sometimes, it is difficult to distinguish from primary sclerosing cholangitis, and multiple pathological examinations may be required for a definitive diagnosis.

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bubble_chart Treatment Measures

Due to the slow and concealed growth of bile duct cancer, most patients' tumors occur at the hepatic duct confluence. By the time of surgery, the cancer often has already infiltrated surrounding tissues, resulting in a very low surgical resection rate—less than 20%. In a group of 50 cases at Zhongshan Hospital, only 2 could be resected. If the cancer at the hepatic duct confluence is resectable, anastomosis between the bilateral intrahepatic bile ducts and the jejunum is required. Some also advocate extended right hepatic lobectomy. After resection of middle-third bile duct cancer, a bile duct-jejunum anastomosis can be performed, along with clearance of the lympho-fatty tissue in the hepatoduodenal ligament. For lower-third bile duct cancer, a pancreaticoduodenectomy may be performed. For unresectable bile duct cancer, palliative treatment primarily aims to relieve jaundice. This can involve placing a T-tube, Y-tube, or U-tube in the dilated bile duct proximal to the obstruction for external drainage. If feasible, an anastomosis between the dilated bile duct or gallbladder and the jejunum can be performed. In recent years, percutaneous transhepatic external drainage methods have been increasingly used, such as placing a drainage tube into the intrahepatic bile duct proximal to the obstruction (PTCD) or inserting a catheter past the tumor stenosis to place an internal stent (PABD), allowing bile to flow into the duodenum. These methods not only alleviate symptoms but also improve liver function, creating conditions for future radiotherapy and chemotherapy and, to some extent, prolonging the patient's life. Terblanche reported that among 15 bile duct cancer patients who underwent external drainage followed by radiotherapy, 10 survived for more than 1 year, and 2 survived for more than 2 years. The prognosis for bile duct cancer is poor. The average survival time for the resection group is 13 months, with very few surviving 5 years. The decompression tube group has an average survival of 6–7 months, with few exceeding 1 year.