When we think of cancer affecting the gastrointestinal tract, stomach or colorectal cancer may be the first thing to jump to mind. These two are the most common gastrointestinal cancers in Singapore (https://gastrohealth.com.sg/), but those are not the only cancers that can affect the GI tract.
What is the GI tract?
Everything that we consume passes through the body’s gastrointestinal tract, which starts from the mouth with different organs connecting all the way to the anus. The upper GI tract, composed of the esophagus, stomach, and small intestines, is responsible for digesting and processing food to get nutrients and energy for the body.
Whatever remains is processed by the large intestine (colon) and rectum, which is then expelled from the body as waste.
The gastrointestinal tract is composed of the following organs:
- Mouth
- Esophagus
- Stomach
- Small intestine
- Large intestine
- Rectum
- Anus
Also considered part of the GI tract are:
- Liver
- Pancreas
- Gallbladder
What are the most common types of cancers affecting the gastrointestinal tract?
The gastrointestinal cancers that are most common include:
- Colorectal cancer
- Gastric (stomach) cancer
- Esophageal cancer
- Liver cancer
- Pancreatic cancer
Colorectal cancer. This type of cancer affects the large intestine, which is the last organ to process everything that we eat and passes through the digestive system. It has three parts:
- Cecum
- Colon
- Rectum
Abnormal growths, or polyps, can develop inside the large intestine. The polyps attached to the lining of the colon may not be cancerous (benign). Cancer develops when a polyp undergoes changes in the DNA which causes cancerous cells to grow.
Older adults are most at risk of developing colorectal cancer. However, this disease has been observed increasing among younger adults. The risk of colorectal cancer is high for people who have a family history of the disease and those diagnosed with inflammatory bowel disease (e.g. Crohn’s disease, ulcerative colitis).
Some causes have also been linked to lifestyle factors, such as having a low fibre diet, heavy consumption of alcohol, and obesity.
Gastric (stomach) cancer. Malignant cells that cause gastric cancer usually grow in the innermost layer of the stomach, called mucosa. This part of the stomach is responsible for the production of stomach acids and enzymes used for digesting food.
Gastric cancer usually does not exhibit any kind of symptom during its onset. Hence, it is important for individuals who have a family history of this disease to get cancer screening at an early age in order to detect its presence.
The chances of being able to manage and treat this condition becomes higher when it is discovered in its initial stages. Likewise, adults that are over the age of 45 should submit themselves to screening to be sure that they do not have any cancerous growths in their stomach.
Esophageal cancer. The oesophagus is a muscle-layered tube that is responsible for transporting the food from the back of the throat to the stomach. It is also known as the “food pipe.” There are two types of cancer that can affect the oesophagus:
- Adenocarcinomas
- Squamous cell carcinomas
Adenocarcinomas are cancer cells that develop in certain glands in the oesophagus, while squamous cell carcinomas begin in the cells that line the top layer of the oesophagus.
People who are heavy consumers of alcohol and users of tobacco double the risk of developing squamous cell carcinomas. On the other hand, adenocarcinomas can occur when the lower portion of the oesophagus becomes damaged due to acid reflux.
Gender also plays a role in risks of developing esophageal cancer. Studies show that men are more likely to get esophageal cancer, specifically Adenocarcinomas, four times than women.
Liver cancer. The liver has a very important function in the body—it filters and removes toxins and waste from the blood. Aside from this, it helps the body get nutrients from the food we eat by secreting bile and enzymes to digest food.
When cells in the liver develop and severely break down over a period of time, they have the chance to become tumours. These tumours may either be benign or malignant. Malignant tumours have the possibility to spread to the other organs of the body or tissues surrounding the liver.
Liver cancer is classified as primary and secondary. Liver cancer is considered primary when it begins in the liver and secondary if the cancer only metastasizes to the liver from other organs. Primary liver cancer is further categorized into 4 types:
- Angiosarcoma
- Bile duct cancer
- Hepatoblastoma
- Hepatocellular carcinoma
Pancreatic cancer. The pancreas is a pear-shaped organ located behind the stomach that functions to produce substances like enzymes and insulin to support digestion. Cancer cells begin to develop in the pancreas through tumour growths.
This influences the organ’s ability to function well and has the possibility to affect surrounding organs and tissues when left untreated. There are two types of pancreatic cancer:
- Pancreatic endocrine cancer
- Pancreatic exocrine cancer
Pancreatic endocrine cancer, also known as Islet cell cancer, is a cancer that develops in the hormone-producing cells in the pancreas. Symptoms of this type of cancer can be caught when the hormones produced by the pancreas become abnormally high.
Because of its symptoms and nature of developing slowly, islet cell cancer can be diagnosed and treated in its earlier stages.
Pancreatic exocrine cancer, or Adenocarcinoma, are cancer cells that occur in the lining of the pancreas’ ducts. This cancer does not usually show any symptoms and can advance rapidly.
Gastrointestinal cancer symptoms
In most cases, the symptoms of gastrointestinal cancers do not show unless the disease has become more severe. Likewise, a number of symptoms may be similar to other gastrointestinal diseases. The usual signs of GI cancers are:
- Appetite loss
- Bleeding
- Bloating
- Changes in bowel movement
- Indigestion
- Pain in the abdominal area
Gastrointestinal cancer management and treatment
In Singapore, gastrointestinal screening is highly recommended for people whose risk of developing GI cancers are high. The same is advised for older adults past the age of 45.
Gastrointestinal cancer screenings are crucial in discovering cancer symptoms affecting the different areas of the digestive system. Early detection increases the possibility of being able to treat and cure the cancer.
You can know more about gastrointestinal cancers in Singapore and what treatments are available by reaching out to Gastrohealth Clinic.
