Gastrointestinal cancers

Cancers of the gastrointestinal tract represented about one in four cancer cases in 2018 but more than one in three cancer-related deaths.


GI malignancies  accounted for 26% of the global cancer burden but 35% of cancer-related deaths. 


A reported 4.8 million new cases of GI  alignancies  and 3.4 million deaths worldwide reported in 2018. 


The rates of all five GI cancers in young adults (aged 25-49 years) have increased in the US.


GI cancer rates in men are two to three times higher than in women. 


Gastrointestinal cancer refers to malignant.   conditions of the gastrointestinal tract including the esophagus, stomach, biliary system, pancreas, small intestine, large intestine, rectum and anus. 


Combined cancers of the esophagus,esophagogastric junction and stomach represent the second leading cause of cancer related mortality globally, with over 1.3 million deaths in 2020 which is 13% of all cancer deaths.


The symptoms relate to the organ affected.


Symptoms can include obstruction,  abnormal bleeding or other associated problems. 


The diagnosis often requires endoscopy, followed by biopsy of suspicious tissue. 


The treatment depends on the location of the tumor, and the type of cancer cell and whether it has invaded other tissues or spread elsewhere. 


The GI tract and the accessory organs of digestion, the pancreas, liver, gall bladder are responsible for more cancers and more deaths from cancer than any other system in the body.


Geographic variation in the rates of different gastrointestinal cancers is significant.


((Esophageal cancer)) is the sixth-most-common cancer in the world, and its incidence is increasing.


Some three to five males are affected for each female.


The incidence of esophageal squamous cell carcinoma (SCC) is more than a hundred times that of adjacent areas, extends from northeastern China through central Asia to northern Iran.


There are two main types of ((esophageal cancer)): adenocarcinoma and squamous cell carcinoma. 


Worldwide, the incidence of each type is about the same, but in developed countries like North America and Europe adenocarcinoma is the more common.


Cancer of the esophagus is often detected late.


Esophageal cancer accounted for 572,000 new cases and 508,000 deaths in 2018, making it the sixth-most-deadly cancer worldwide. 


If caught soon enough, patients can have a five-year survival rate of 90% or above. 


The overall five-year survival rate for advanced esophageal cancer is about 20%, and in the United States it is about 15%.


((Gastric cancer))  is the fourth-most-common type of cancer and the second-highest cause of cancer death globally.


Eastern Asia (China, Japan, Korea, Mongolia) is a high-risk area for gastric cancer.


North America, Australia, New Zealand and western and northern Africa are areas with low risk.


The most common type of gastric cancer is adenocarcinoma.


((Gastric adenocarcinoma)) causes about 750,000 deaths each year.


Gastric cancer accounted for more than 1 million new cases and nearly 800,000 deaths in 2018. 


Factors contributing  to the development of gastric cancer include:  diet, smoking and alcohol consumption, genetics, and infections-Helicobacter pylori or Epstein-Barr virus and pernicious anemia.


Chemotherapy improves survival compared to best supportive care.


Pancreatic cancers are classified as endocrine or nonendocrine tumors. 


The most common ((pancreatic cancer)) is ductal adenocarcinoma.


Risk factors for pancreatic cancer include: advancing age, smoking, chronic pancreatitis, and diabetes.


Pancreatic cancer has a poor prognosis, with a five-year survival rate of less than 5%. 


Wealthy countries have incidence and death rates three to four times higher than do less-developed countries.


When diagnosed, it is usually at an advanced, inoperable stage.


Only one in about fifteen to twenty patients is curative surgery attempted in pancreatic cancer.


Pancreatic cancer tends to be aggressive, and it resists radiotherapy and chemotherapy.


((Hepatocellular carcinoma))typically results from a prolonged Hepatitis B or C infection or as a result of cirrhosis from chronic alcoholism. 


In eastern Asia, hepatitis B infections and aflatoxins are the primary risk factors for hepatocellular carcinoma, while in Japan and Europe hepatitis C is the main cause for hepatocellular carcinoma. 


Decreases in both infections and aflatoxins explain declines in liver cancer rates in those regions, whereas in lower-risk areas, increasing liver cancer rates caused by more widespread obesity and diabetes may be offsetting declines in HBV and HCV rates.


Treatment options include surgical resection, embolization, ablation or a liver transplant.


Cancers of the gallbladder are typically adenocarcinomas, and are common in elderly women. 


((Gallbladder cancer)) are strongly associated with gallstones, porcelain gallbladder appearance on ultrasound, and the presence of polyps within the gallbladder. 


The prognosis for gallbladder cancer is poor.


MALT lymphoma is a cancer of the mucosa-associated lymphoid tissue, usually in the stomach.


Gastrointestinal stromal tumors represent from 1% to 3% of gastrointestinal malignancies.


Cancers of the biliary tree, include ((cholangiocarcinoma)).


((Colorectal cancer)) was a disease of old age.


Colorectal cancer typically originates in the secretory cells lining the gut.


Risk factors for colorectal cancer include diets low in vegetable fibre and high in fat. 


Colorectal cancer in the young is often associated with hereditary syndromes like Peutz-Jegher’s, hereditary nonpolyposis colorectal cancer or familial adenomatous polyposis.


Colorectal cancer has a good prognosis when detected early.


((Anal cancer)) landmark is the pectinate line (dentate line), located about 1–2 cm from the anal verge.


The anal verge is where the anal mucosa of the anal canal becomes skin.


Anal cancers located above this line are more likely to be cancers, while those located below are more likely to be squamous cell carcinomas that may ulcerate. 


Anal cancer is strongly associated with ulcerative colitis and the sexually transmissible infections HPV and HIV. 


Anal cancer is treated by excision and radiotherapy, or with external beam radiotherapy and adjunctive chemotherapy. 


The five-year survival rate with the latter procedure is above 70%.


Gastrointestinal carcinoid tumor is arare, slow-growing form of cancer that affects certain cells in the lining of the stomach and intestines. 


Gastrointestinal ((carcinoid tumors)) usually occur in the appendix, small intestine, or rectum. 


((Esophagus adenocarcinoma)) tend to arise in a field defect called ((Barrett’s esophagus)).


((Barrett’s esophagus)) is the dominant pre-malignant lesion of esophageal adenocarcinoma, and has prevalent epigenetic alterations.


((Gastric cancer)) develops within field defects of the stomach with atrophic gastritis and intestinal metaplasia: these lesions represent the cancerization field in which intestinal-type gastric cancers develop.


There is greater than 5-fold reductions were found in four miRNAs in tumor-adjacent tissues and gastric cancers as compared to those miRNA levels in normal gastric tissues.


Cardia gastric cancer is associated with obesity and gastroesophageal reflux disease, and is more prevalent in Western countries.


Noncardia gastric cancer is more prevalent in countries with higher rates of Helicobacter pylori infection. 


Cytotoxic chemotherapy is the mainstay of treatment for advanced gastric cancer, and adding trastusumab or trastusumab deruxetan are  approved by them biomarker target agents in HER2 positive advanced gastric cancer.


Checkpoint inhibitor combination with first line oxaliplatinum based chemotherapy is now considered for gastric cancers, especially in those with PD-L1 expression positive scores.


Primary and secondary prevention of gastrointestinal cancers:  reducing consumption of tobacco and alcohol, obesity control, immunizing populations against hepatitis B virus infection, and screening for colorectal cancer.


Eastern Asia has the highest rates of GI cancer 12.2 per 100,000 person-years, followed by eastern Africa (8.3) and southern Africa (7.4). 


China alone accounts for 54% of the global burden of gastrointestinal cancers.


The large percentage of these cancers in developing countries are squamous cell  linked to tobacco use, heavy alcohol consumption, opium intake, air pollution, and diet.


Colorectal cancer is related to higher dietary intake of fats, sugar, and animal-source foods and increases in sedentary behavior and obesity. 


Prevention remains key in GI cancers and lifestyle choices like smoking, alcohol intake, and physical activity are all drivers of GI cancer burden. 



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