Major Types of Colon Cancer: Adenocarcinoma and More

Adenocarcinoma

It is the most common type of colon cancer, which accounts for almost 95% of all cases in people. This type of cancer usually develops in the glandular cells that line the inside of the colon and rectum. Generally, this cancer starts as a tissue growth, which is known as a polyp. The adenomas used to develop as a cancer.

Key characteristics

Here are some significant characteristics of adenocarcinoma in the colon.

These may include:

• These cancer often starts as a polyps
• Slow-growing but it can become invasive if goes unnoticed
• Subtypes includes mucinous adenocarcinoma and signet ring cell adenocarcinoma
• It may not show any symptoms until it reaches the advanced stage
• It can cause blood in the stool (poops), which usually not noticed immediately
• Common symptoms may include abdominal pain, diarrhea, constipation

Risk factors

There are several factors that increase the risk factors of adenocarcinoma in the colon.

These may include:

• Age 
• Family history of colorectal cancer
• Inherited genetic syndromes (Lynch syndrome)
• Lifestyle factors including diet
• Physical activity
• Inflammatory bowel disease
• Diabetes
• Insulin resistance

Gastrointestinal Stromal Tumors

These types of tumors are mesenchymal tumors that might originate in the interstitial cells of Cajal (ICCs), which are used to help and control the muscles of the digestive system. Many studies have shown that 50% of GISTs develop in the stomach. 

GISTs are commonly classified as sarcomas, or cancers that usually develop in the connective tissue, including fat, muscle, blood vessels, deep skin tissues, bones, cartilage, and nerves.

Key characteristics

Here are some of the important characteristics of GISTs in colon.

These may include:

• This type of cancer can develop in the GI tract, including the colon.
• Usually detected in the older-aged people
• Two types, including malignant and benign
• Targeted therapy with the use of medicine like imatinib (Gleevec) for malignant GISTs

Risk factors

There are some factors that increase the risk of developing GISTs in the colon. The risk factor may include:

• People above the age of 40
• Gender, GISTs are common in men
• Inherited genetic syndromes (Familial GIST Syndrome, Neurofibromatosis type 1 (NF1) and carney-stratakis syndrome)
• Family history of GISTs

Squamous cell carcinoma

This type of cancer develops in the squamous cells that are not normally found in the colon. It is extremely rare and often associated with chronic inflammation or infection. This type of colon cancer is often diagnosed at an advanced stage and has a poor prognosis when compared to adenocarcinoma. 

Characteristics

• Squamous cell carcinoma accounts for less than 1% of all cancers.
• This cancer is aggressive in nature and locally invasive and tends to progress rapidly.
• Most cases are diagnosed in the advanced stage due to any future health complications.

Risk factors

Here are some of the factors that influence the risk of developing this cancer. 

These may include:

• People above the age of 65
• Inflammatory bowel disease
• Family history of colon cancer
• Inherited syndromes
• Lifestyle factors
• Smoking habits
• Excessive alcohol consumption
• Parasite infection

Why does understanding these types of cancers matter?

Colon cancer usually develops in the colon or rectum. For instance, if the cancer develops in the colon, then it may be referred to as colon cancer. However, if the cancer develops in the rectum, it is then known as rectal cancer. Regardless of their origin, most of these cancers share a lot in common, which is why they are known as colorectal cancer.

Understanding different types of colon cancer might help with planning more effective and personalized treatments for the patients. Adenocarcinomas in the colon may usually respond well to the standard treatment, such as chemotherapy; meanwhile, gastrointestinal stromal tumors require targeted therapies for the cure or remission from this cancer.

Lymphomas, depending on the type and stage, might not require surgery. It can be effectively treated with chemotherapy, radiation therapy, or sometimes targeted therapies.