Pancreatic Cancer - Causes

The causes of development and pathogenesis of pancreatic cancer, as well as cancer in general, are not clear. However, it has been noted that factors such as chronic pancreatitis, cysts and injuries of the pancreas, chronic diseases of the biliary tract, alcoholism, addiction to very fatty and spicy food, diabetes, radiation exposure (in case of violation of safety regulations at work and in emergency situations), some chemical hazards, among which benzidine and beta-naphthylamine are most often mentioned, contribute to an increase in cancer incidence.

10% of pancreatic cancer cases have a genetic cause, such as genetic mutations or association with syndromes such as:

• A hereditary breast and ovarian cancer syndrome caused by mutations in the BRCA1 or BRCA2 genes.
• Hereditary breast cancer caused by mutations in the PALB2 gene.
• Familial atypical melanoma of multiple nevi (FAMMM) syndrome caused by mutations in the p16/CDKN2A gene and associated with melanomas of the skin and eyes
• Familial pancreatitis, usually caused by mutations in the PRSS1 gene.
• Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer (HNPCC), is most often caused by a defect in the MLH1 or MSH2 genes.
• Peutz-Jeghers syndrome, caused by defects in the STK11 gene. This syndrome has also been linked to polyps in the digestive tract and other cancers.

Pathomorphology of pancreatic cancer

The tumor can be localized in any part of the pancreas or grow into it entirely, but usually in 70-75% of cases, according to different authors, it is localized in the head of the pancreas, in 20-25% of cases - in its body and about 10% - in the tail area. Macroscopically, it is a limited gray-white node; it can be of varying density. Cancer develops from the epithelium of the excretory ducts or, less often, from the parenchyma of the gland. Even less often, the tumor develops from the epithelium of the pancreatic islets. Adenocarcinomas - the most common type of pancreatic cancer - have a fairly soft consistency and usually grow relatively quickly. Another, also common, form of cancer is scirrhus, consisting of small, predominantly polygonal cells with abundant proliferation of connective tissue. Other forms of cancer are less common. Cancerous tumors of the head of the pancreas are usually not large, in contrast to cancerous neoplasms of its body and tail. A tumor located in the head of the pancreas can compress the common bile duct, grow into the duodenum, stomach, and liver. Tumors of the body and tail of the gland grow into the left kidney, spleen, and spread through the peritoneum. Pancreatic cancer metastasizes to regional lymph nodes, liver, lungs, adrenal glands, bones, and less often to other organs. Tumors localized in the tail of the pancreas are more prone to generalized metastasis.

Histologically, cancer in situ, adenocarcinoma, epidermoid cancer, adenoacanthoma and anaplastic cancer are distinguished. Cancer in situ in the ducts is more common. The most typical for the pancreas is adenocarcinoma, with its scirrhous variants predominating. Areas with a colloid cancer structure may be found.

Epidermoid pancreatic cancer is rare, more common are the so-called adenoacanthomas, in which epidermoid structures alternate with areas of glandular cancer. Among anaplastic cancers, round cell, spindle cell and polymorphic cell variants are distinguished. Recently, immunohistochemical markers have been increasingly used to clarify the histogenesis of pancreatic cancer: carcinoembryonic antigen and cancer antigen 19-9.

Metastatic cancer also occurs in the pancreas, although relatively rarely (metastases from the stomach and other internal organs). On the other hand, tumors of neighboring organs - the stomach, bile ducts, and colon - can grow into the pancreas.

Classification of pancreatic cancer. Usually, 4 stages of cancer development are distinguished: I and II depending on the size of the tumor (but in the absence of metastases), III and IV in the presence of nearby and distant metastases.

• Stage I - the tumor diameter does not exceed 3 cm;
• Stage II - the tumor is more than 3 cm in diameter, but does not extend beyond the organ;
• Stage III A - infiltrative tumor growth into surrounding tissues (duodenum, bile duct, mesentery, vessels, portal vein);
• Stage III B - tumor metastases in regional lymph nodes;
• Stage IV - distant metastases.

There are also other classifications of cancer in this location.

[ 1 ], [ 2 ], [ 3 ], [ 4 ]