Different Types of Cancer which Affects the Digestive System

The Gastrointestinal tract, which is synonymous with the digestive system, is one of the most important conduits in the human body. This is a 25-feet long canal that starts at the mouth and ends at the anus. It either houses or connects with various organs of the digestive system. Needless to say, like any other part of the body, the GI tract is vulnerable to cancer. GI cancer is an umbrella term for as many as 10 different cancers in the body. DNA mutations that cause abnormal growth or multiplication in the cells that line the GI tract cause these cancers.

1. Stomach (gastric) cancer

In this, malignant cancer cells start lining the walls of the stomach. The stomach wall is made of 3 layers – the innermost mucosal layer, the muscularis layer in the middle, and the outermost serosal layer. Most of the stomach cancers (95%) affect the mucosal layer and are called adenocarcinoma, which spread to other layers of the stomach wall. Other, rarer stomach cancers include carcinoid tumors, squamous cell carcinoma, stromal tumors and lymphoma.

Initial symptoms of stomach cancer include heartburn, bloated feeling after meals, mild nausea and low appetite.

Advanced symptoms include difficulty in swallowing, blood in the stools, build-up of fluid in the abdomen (ascites), vomiting, jaundice symptoms (yellow skin and eye-whites), stomach pain and weight loss for no known reason.

2. Bowel (colorectal) cancer

 Here, malignant cancer cells line the walls of the large intestine (LI), and depending on which part of the LI, there are 3 types: colon cancer, rectal cancer and colorectal cancer. Again, chemically or structurally speaking, bowel cancers are either sarcomas, lymphomas, carcinoid, stromal or squamous-cell tumors.

Signs and symptoms include: a pain or lump in the rectum or bowel, rectal bleeding or blood in the stools, gas, bloating or cramps in the bowel or rectum, constipation or diarrhea that lasts for several days, smaller or more frequent bowel movements, changes in the appearance or consistency of stools including narrower stools or mucus in the stools, a feeling of fullness in the bowel even after movement, unintended weight loss, weakness and fatigue.

3. Liver cancer

 Depending on which part of the liver the cancer started developing in, liver cancers are of 2 types:

1. Hepatocellular carcinoma: the cancer starts in the main cells of the liver and is the more common type. Being male and 50 years or older increases the risk of this type.
2. Cholangiocarcinoma: Here, the cancer starts in the bile-duct which is a tube connecting the liver to the gall-bladder and small intestine.

Primary liver cancers, or those that originate in the liver are rare. Most of the time, liver cancers are secondary or metastatic. That is, cancer cells from a tumor in another part of the body travel through the blood or lymphatic system and get lodged in the liver after which they start multiplying.

Symptoms of liver cancer include: Low appetite and/or nausea, discomfort in the Right Upper Quadrant (RUQ) of the abdomen, unexplained weight loss, a hard lump in the RUQ, pain in the upper back and right shoulder, fatigue and jaundice symptoms such as yellow skin and eye-whites.

4. Esophageal cancer

 The esophagus is a 10-inch long tube that connects the throat with the stomach. 15% of all esophageal cancers develop in the top one-third of this tube, 50% in the middle one-third and 35% in the bottom one-third. Squamous-cell carcinoma and adenocarcinoma are the most common types of esophageal cancers, chemically speaking.

Symptoms include: coughing up blood, difficulty in swallowing, throwing up or reflux of food, hoarse voice, cough that doesn’t go away, acid reflux (similar to Gastro Esophageal Reflux Disease) and weight loss.

5. Pancreatic cancer

 The pancreas is shaped like a pyramid sitting on top of a sphere. The pancreatic duct is a thin canal that lies in the center and runs throughout the pancreas. The sphere which forms the base is called the head and as much as 60% of pancreatic cancers are found here. The remaining 40% is found in the pyramid which constitutes the body and tail of the pancreas. The cancer originates in the pancreatic duct and soon spreads to the surrounding nerves, tissues and blood-vessels. It even metastasizes (spreads) to surrounding organs or other parts of the body through the blood and lymphatic system.

Symptoms include: weight loss, pain in the upper abdomen, onset of diabetes mellitus (in few cases), nausea and vomiting, jaundice symptoms (yellow skin and eye-whites) in case the cancer blocks the bile duct.

6. Anal cancer

 Anal cancer is not the same as bowel cancer which occurs in the descending colon of the large intestine. Anal cancer occurs in the anal canal which is a 3.8 cm long tube connecting the rectum with the anal opening. Most cancers of the anus are squamous cell carcinomas which affects cells that line the surface of the anal canal.

Symptoms include: a change in bowel habits, bleeding from the anus or rectum, a lump near the anus, pain or pressure in the area around the anus, and itching or discharge from the anus.

7. Bile duct cancer (BDC)

The bile ducts perform an important function of passing on the bile juice to the small intestine. Two ducts coming from the liver and one duct coming from gall bladder join to form the common bile duct. The common bile duct and pancreatic duct then join or merge at a point on the small intestine. Depending on which part of the bile-duct network the cancer originated in, bile duct cancers are of 4 types: Klatskin tumor, intrahepatic BDC, common BDC and multifocal BDC.

Symptoms include: Jaundice symptoms (yellow skin and eye-whites, itchy skin, abdominal pain and fever.

8. Gastrointestinal carcinoid tumor

Neuroendocrine cells that are found in the inner lining of the digestive tract make hormones that regulate the working of the digestive juices and also the muscles in the GI tract. When some of these cells become cancerous, the condition is called GI carcinoid tumor. The cancer starts as small polyps that gradually grow and spread. They are found in the rectum, small intestine and appendix. These cancerous cells produce their own hormones which can affect the normal working of the digestive, respiratory and circulatory systems.

Symptoms include: weight loss, flushing, wheezing, severe diarrhea, low appetite, sudden changes in blood pressure and increased heart rate.

9. Gallbladder cancer (GBC)

 Bile juice is required to digest or break down fats consumed through food. It is secreted by the liver and passed on from the liver to the small intestine through the 2 bile-ducts and thereafter into the common bile-duct. In between meals, when there is no fat to be digested, the bile produced by the liver is stored in the gallbladder. Again when there is food in the digestive system, some of the bile stored in the gallbladder is also released along with some bile from the liver, into the common bile duct.

Gall-bladder cancer occurs in the glandular tissue and lining of the gallbladder. Most GBCs are squamous cell carcinoma, lymphoma or sarcoma type.

Symptoms include: unusual lumps in the abdomen, jaundice symptoms, pain in the RUQ, fever, bloated feeling in the abdomen, unexplained weight loss, nausea and vomiting.

10. Small intestine cancer

 The small intestine is a long tube that connects the stomach to the large intestine. It is several feet long and folds several times to fit inside the abdominal cavity. Cancerous cells start appearing in the glandular cells that line the small intestine, especially closer to the stomach. As they grow, they start blocking the intestine. Small Intestine cancer is quite rare and is of 4 types: Gastrointestinal stromal tumor, sarcoma, lymphoma and carcinoid tumors.

Symptoms include: blood in the stools, pain or cramps in the middle of the belly, unexplained weight loss and an unusual lump in the abdomen.

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