Colorectal Cancer and Colon Cancer are sometimes mistaken to mean the same thing. But we are going to clarify that in this guide. Would you like to know the differences between these two types of cancer? Then you should read through this guide.
What Is Colorectal Cancer?
Colorectal cancer starts in the colon or the rectum. These cancers can also be called colon cancer or rectal cancer, depending on where they start. Colon cancer and rectal cancer are often grouped together because they have many features in common.
Cancer starts when cells in the body start to grow out of control.
Symptoms
Colorectal cancer may not cause symptoms in the early stages. If it does, they may include:
- changes in bowel habits
- diarrhea
- constipation
- a feeling that the bowel does not empty fully
- blood in feces that makes it look dark brown or black
- bright red blood from the rectum
- abdominal pain and bloating
- feeling full, even when a long time has passed since a meal
- fatigue or tiredness
- unexplained weight loss
- anemia
If a doctor finds sigof anemia during a routine medical check, they may suggest screening for colorectal cancer. Or, they may diagnose it during routine screening.
Around of people with this type of cancer receive the diagnosis when the disease is in an early stage.
The symptoms can be similar to those of many other health conditions. Anyone with concerabout these symptoms should seek medical advice.
Types of colorectal cancer
Colorectal adenocarcinoma
“Adeno” is a prefix meaning gland. “Carcinoma” is a type of cancer that grows in epithelial cells, which line the surfaces inside and outside the body. Adenocarcinomas develop in the lining of the large intestine (colon) or the end of the colon (rectum). They often start in the inner lining and spread to other layers.
There are two less common subtypes of adenocarcinomas:
Mucinous adenocarcinoma is made up of about 60 percent mucus. The mucus may cause cancer cells to spread more quickly and become more aggressive than typical adenocarcinomas. Mucinous adenocarcinomas account for 10 percent to 15 percent of all rectal and colon adenocarcinomas.
Signet ring cell adenocarcinoma accounts for fewer than 1 percent of all colon cancers. Named for its appearance under a microscope, signet ring cell adenocarcinoma is typically aggressive and may be more difficult to treat.
Most information about colorectal cancer refers to colorectal adenocarcinoma, the most common type. Estimates suggest that 4.1 percent of people may develop colorectal cancer during their life, according to the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) Program.
Colorectal adenocarcinoma symptoms generally include:
- Abdominal pain and tenderness
- Blood in stool
- Changes in bowel habits, such as diarrhea or constipation
- Thin stools
- Unexplained weight loss
Getting screened for colon cancer may detect the disease before it starts causing symptoms. The American Cancer Society (ACS) and the U.S. Preventive Services Task Force both recommend adults start colon cancer screening at age 45.
Diagnosing colorectal cancer starts with a colonoscopy, which lets doctors see inside the rectum and colon. If sigof colorectal cancer are discovered during a colonoscopy, other tests will follow. A biopsy may be performed, which involves removing a small piece of potentially cancerous tissue (sometimes during a colonoscopy) and analyzing the sample for the presence of cancer. Once a diagnosis is confirmed by a colonoscopy and a biopsy, blood tests and imaging tests, such as computed tomography (CT) scaand magnetic resonance imaging (MRI) scans, may be used to help learn more about cancer and whether it’s spread.
Common treatment optiofor colorectal adenocarcinomas include:
- Surgery
- Chemotherapy
- Radiation therapy
- Targeted therapy
Gastrointestinal carcinoid tumors
Carcinoid tumors develop in nerve cells called neuroendocrine cells, which help regulate hormone production. These tumors are among a group of cancers called neuroendocrine tumors (NETs). Carcinoid tumor cells are slow-growing and may develop in the lungs and/or gastrointestinal tract. They account for about 1 percent of all colorectal cancers and half of all cancers found in the small intestine.
Potential symptoms differ depending on where the tumor grows. A carcinoid tumor in the appendix typically doesn’t cause symptoms, unless it begito block the pathway from the appendix to the intestine, leading to appendicitis symptoms such as fever, nausea, and vomiting.
Tumors in the small intestine or colon may cause stomach cramps and pain, weight loss, tiredness, bloating, and other stomach problems. Carcinoid tumors in the rectum may cause pain, bleeding, and constipation. In the stomach, carcinoid tumors typically don’t cause symptoms.
Carcinoid tumors also sometimes produce hormones that may lead to various symptoms, depending on the type of hormone. For example, 10 percent of people with these tumors may experience flushing in the face, diarrhea, wheezing and rapid heartbeat due to certain hormone-like substances that are released by the tumor, according to the ACS.
Depending on where they develop, gastrointestinal carcinoid tumors may be discovered in various ways. For example, a tumor in the appendix may be found after it causes appendicitis, and the appendix is removed. Rectal tumors may be detected during routine checkups.
Several tests are used to diagnose carcinoid tumors in the abdominal tract, including blood tests, urine tests, imaging scans, endoscopy, and colonoscopy.
Gastrointestinal carcinoid tumor treatment optioinclude:
- Surgery
- Radiation therapy
- Chemotherapy
- Hormone therapy
Similarities Between Colon and Colorectal Cancer
Besides originating in the large intestine, here are characteristics that colon and rectal cancer have in common:
- Symptoms: Since bloody stools are typical for rectal and colon cancer, red or dark-colored spots/streaks may be noticeable with bowel movements. Constipation, gas pain, bloating, and abdominal discomfort are also sigof colon and rectal cancer.
- Risk factors: Being overweight, smoking, alcohol use, eating a low-fiber diet, the presence of polyps, increased age, type 2 diabetes, and family history are risk factors for both colon and rectal cancer.
- Incidence: Although colon cancer is slightly more prevalent than rectal cancer, combined colorectal cancers are the third leading cause of cancer-related deaths in the United States. In addition, colorectal cancers affect more Black Americathan White Americans.
- Genetics: Colon and rectal cancer share genetic mutatioresponsible for their growth, including familial adenomatous polyposis.
- Screening: Early detection of colon and rectal cancer is essential to early diagnosis and treatment. Colon and rectal cancer screening is the same and includes stool-based tests, visual exams (colonoscopy and flexible sigmoidoscopy), and polyp removal.
Differences Between Colon and Colorectal Cancer
Anatomy
Colon and rectal cancers start in different parts of the large intestine. Colon cancers start in the first (and longest) part of the large intestine. Rectal cancers, on the other hand, start in the last several inches of the large intestine.
The blood supply, lymphatic drainage, and nerve supply of the colon and rectum are not the same. In addition, the rectum is close to other organs, and unlike the colon, it lacks a protective outer layer called the serosa. Therefore, metastasis (spread) of the disease is more likely to occur with rectal cancer than with colon cancer.
Sex Differences
While colon cancer is fairly equal between the sexes, women are more likely to develop right-sided colon cancer, which is more aggressive than left-sided. A larger number of men than women develop rectal cancer.
Disease Recurrence
When cancer comes back after treatment and surgery, it is called disease recurrence. Cancer can return locally (in the area where it originated) or can be metastatic (spread to other tissues or organs).
Although recurrence rates depend on several factors, two separate studies show that local recurrence of rectal cancer varies from 7% to 21% for rectal cancer versus about 4% to 11% for colon cancer.
Invasion of Nearby Tissue
Cancer cells invade neighboring tissue and orgaby entering the bloodstream or the lymph system and traveling to other areas of the body. Since rectal tumors are close to blood vessels, they easily spread. One study found that rectal cancer tends to spread to the thoracic orga(lungs) and the nervous system, whereas colon cancer often spreads to the liver.
Colostomy
People who undergo surgery for rectal cancer have a greater chance of having a permanent colostomy. If the tumor is low in the rectum, the anal sphincter may need to be removed, requiring a life-long colostomy.
Treatment
- Surgery: Removing cancer is essential for colorectal treatment. Surgery for colon cancer may be recommended at any disease stage, while surgery without chemotherapy or radiation therapy is typically prescribed for stage I and II colon cancer. In contrast, surgery for rectal cancer is usually performed for stages I-III.
- Surgical difficulty: Rectal cancer surgery is more complicated than colon cancer surgery, as the rectal tumor can be difficult to access without damaging surrounding structures. Therefore, surgical complicatiotend to be worse with the removal of rectal cancer.
- Radiation therapy: Radiation is not commonly used for colon cancer, but most rectal cancers are treated with radiation before surgery to shrink the tumor before removal.
- Chemotherapy: Chemotherapy is used for both colon and rectal cancer depending on the stage. However, different types of chemotherapy drugs are used for each disease.
- Targeted therapy: If there is a molecular mutation that is causing the colon or rectal cancer to grow, then medicatiothat target the specific mutation may be available for use in both diseases.
- Immunotherapy: Medicatiothat destroy cancer cells by increasing immune system response are called immunotherapy. These treatments are available for both colon and rectal cancer.
- Clinical trials: Finding new cutting-edge therapies can be helpful in the treatment of colon and rectal cancer.
Conclusion
To conclude, colorectal is a cancer that starts in the colon or the rectum. Meanwhile, colon cancer is cancer that begiin the colon.
Colon cancer is generally placed under the umbrella of colorectal. This is because colon cancer and rectal cancer have a large amount of overlap both biologically and in qualities such as symptoms and risk factors.
There are some differences between CRC and colon cancer, especially when it comes to surgical treatments. This is because the type of surgery that’s used can depend on if the cancer is in the colon or the rectum.