Pancreatic cancer is a malignant tumor of the exocrine gland of the pancreas, manifesting as abdominal pain, loss of appetite, emaciation and jaundice, with high malignancy and poor prognosis. In recent years, the incidence of pancreatic cancer has increased significantly, and the age of onset is 45-65 years old, and the ratio of men to women is 1.58:1. However, the cause of pancreatic cancer is still unknown, and domestic and foreign studies found that it may be related to the following 8 factors.
1. Smoking
The accumulation of carcinogens such as nitrosamines in the body of long-term smokers will also increase, and the risk of developing cancer will also increase.
② Smoking causes pancreatic cancer probably because the carcinogens produced by smoking enter the body through the lungs or upper gastrointestinal tract and then enter the pancreas through the bloodstream, or return to the pancreas through the duodenum, and the metabolites of nitrosamines and nicotine produced by smoking can be detected in the pancreatic fluid of smokers.
The risk of pancreatic cancer in smokers is 3-6 times higher than that of nonsmokers, but quitting smoking can effectively reduce the incidence of pancreatic cancer, and the risk of pancreatic cancer decreases with the number of years of smoking cessation, and the risk of pancreatic cancer in those who have quit smoking for more than 10 years is similar to that of nonsmokers, and the risk of pancreatic cancer in those who have quit smoking for 15 years is comparable to that of lifelong nonsmokers. The analysis of correlation factors shows that about 25% of pancreatic cancer cases in men can be attributed to smoking, and only 6% of pancreatic cancer cases in women due to low smoking rate.
2. Alcohol consumption
① Long-term alcohol stimulation, on the one hand, can directly damage the pancreatic tissue, and it has been confirmed that alcohol abuse can induce pancreatitis, and repeated attacks may induce cancer; on the other hand, alcohol can act as a solvent for carcinogens, promoting carcinogens to enter the pancreas, creating conditions for the occurrence of pancreatic cancer while tissue damage.
② The possible mechanism of alcohol consumption leading to pancreatic cancer is that alcohol consumption can enhance the response of the pancreas to cholinergic and pancreatic enzymes and cause increased secretion of protein-rich pancreatic juice, and secondly, alcohol consumption increases the fragility of pancreatic lysosomes, and lysosomal enzymes can activate pancreatic proteases, thus causing damage to the pancreas.
3, coffee
① Coffee contains caffeine, which has a negative effect on normal cells and can contribute to cell aging. Studies have found that coffee is the main cause of cancer by inhibiting DNA repair and inducing the mitotic process before DNA replication is completed.
② The risk of pancreatic cancer in regular coffee drinkers is 2-3 times higher than in non-coffee drinkers, and a survey in the United States showed that the incidence of pancreatic cancer in those who consume more than 181 cups of coffee per week is twice that of those who consume about 7 cups per week, so the development of pancreatic cancer may be related to the long-term consumption of large amounts of coffee, in fact, it is rare to drink 181 cups of coffee per week, and research has found that the occasional appropriate consumption of coffee does not affect the body too much. The study found that occasional consumption of coffee does not affect the body too much.
4. Occupational exposure
① It was found that the risk of pancreatic cancer was increased in occupations exposed to pesticides, and the risk of chemical plant workers exposed to DDT was significantly increased, and the longer the exposure time, the higher the risk, and the derivatives of DDT were found to be associated with the increased risk, and the results remained unchanged after adjusting for other risk factors.
② An increased risk of pancreatic cancer was found among workers in the chemical and petrochemical, rubber, and hairdressing industries, and was thought to be related to aromatic amine exposure.
③ Long-term exposure to certain chemicals such as F-naphthylamine, benzidine and acetylenes may be associated with the incidence of pancreatic cancer, but the pathogenesis needs further study.
5.Chronic pancreatitis
① Chronic pancreatitis can lead to local, segmental or diffuse chronic progressive inflammation of the pancreas, resulting in irreversible damage to pancreatic tissue and pancreatic function. It is conceivable that recurrent episodes of chronic pancreatitis may further evolve into pancreatic cancer.
② Alcoholic and non-alcoholic chronic pancreatitis increase the risk of pancreatic cancer about 10-20 times, and the risk of tropical and hereditary chronic pancreatitis is even higher. Tropical pancreatitis is a rare form of chronic pancreatitis that occurs in southern India and sub-Saharan Africa, mostly in young people, and progresses rapidly. In contrast, the cumulative risk of developing pancreatic cancer in hereditary chronic pancreatitis is 30-40%.
(iii) Molecular-level studies on the relationship between pancreatitis and pancreatic cancer have found that mutations in codon 12 of the K- ras gene, which frequently occur in pancreatic cancer, occur in 25-42% of patients with chronic pancreatitis. In addition, chromosomal instability in patients with chronic pancreatitis also favors the development of pancreatic cancer.
④ The high incidence age of pancreatic cancer is 10-20 years after the age of onset of chronic pancreatitis, the time of inflammatory cancer, from the site of onset, chronic pancreatitis and pancreatic cancer both preferably in the head of the pancreas.
6. Diabetes
① It has been found that it takes a longer time for diabetes to cause pancreatic cancer.
② Abnormal glucose metabolism may cause pancreatic cancer, peripheral insulin resistance and hyperinsulinemia play an important role in the development of pancreatic cancer, it was found that insulin receptors exist in six human pancreatic cancer cell lines, and cell proliferation is dose-dependent with insulin, surface insulin may be one of the important factors to promote the growth of pancreatic cancer, in addition, long-term hyperglycemic state forms chronic stimulation of the pancreas, which may lead to pancreatic cell dysfunction or even cancer. In addition, long-term hyperglycemia may cause pancreatic cell dysfunction or even cancer.
(3) Glucose is the energy source of tumor cells, and the glucose and free fatty acids mobilized during diabetes may provide energy for the generated pancreatic cancer cells, so high blood glucose can be used as a nutrient base to promote the growth of tumor cells.
7. Genetic factors
It is found that about 10%-20% of pancreatic cancer has a family history and the risk of the disease in relatives is about 3-5 times higher. If there are more than 2 cases of pancreatic cancer in the family, the risk of pancreatic cancer in first-degree relatives is about 18 times higher than the general population. Some genetic syndromes have a higher incidence of pancreatic cancer, including hereditary breast cancer with BRCA2 mutation, familial multiple melanoma syndrome, hereditary nonpolyposis colon cancer, Peutz-Jeghers syndrome, and hereditary pancreatitis. The risk of pancreatic cancer in family members carrying this mutation is about 3 to 4 times higher than that of non-carriers.
(2) Oncogene activation, oncogene inactivation and DNA repair gene abnormalities play an important role in the development of pancreatic cancer. 90% of pancreatic cancers can have a point mutation in codon 12 of the K-ras gene.
8. Helicobacter pylori (HP)
It is a source of increased gastrin secretion from HP gastritis and growth inhibitory hormone secreted by a small number of gastric sinus growth inhibitory cells. The continued elevation of gastrin activates the growth of the pancreas, and the potential proliferation increases the susceptibility to pancreatic cancer, so there may be a relationship between H. pylori infection and the occurrence of pancreatic cancer.
In conclusion: Although the etiology of pancreatic cancer is not yet clear, it is a multifactorial, multi-step and multi-stage development process. Through observation and generalization of clinical records, it is found that patients who develop pancreatic cancer often have more than one high-risk factor, and may have two or even more than two high-risk factors.