Difference Between Colon and Rectal Cancer Based on Origin of Cancer, its Symptoms, Diagnosis, Treatment

Most people mistakenly take colon cancer and rectal cancer to be one and the same disease. These two are; however, different health conditions and are treated differently. So, it is very important to diagnose the type of cancer one is suffering from correctly, as this helps to determine the appropriate treatment for the individual and also ascertain the prognosis. Read on to know all about colon vs. rectal cancer.

Colon Vs Rectal Cancer

Colon Vs Rectal Cancer: Difference Between Colon & Rectal Cancers Based On Their Origin

Colon and rectal are both parts of the large intestine, which is the lowest part of the digestive system. Although both colon and rectal cancer affect the large intestine, their place of origin of the cancer within this organ is different. The colon is around 5 feet long and absorbs water from the stool. Colon cancer can begin anywhere in the colon. Rectal cancer on the other hand starts in the rectum, which forms the last 12 cm of the colon. It is in the rectum that the body stores stools until a bowel movement occurs. The location of the rectum and colon is also very important because of the organs, which surround them. Maximum part of the colon is set in the large space between the bottom of the ribcage and the pelvis. The rectum is; however, surrounded by many organs. The bladder is near the rectum. Even the uterus and vagina in females, and the prostate in males, neighbour the rectum. The tightness of space around this rectum can affect the types of surgeries that doctors can perform for removing tumors.

Differences Between Colon and Rectal Cancers Based on Symptoms and Diagnosis

Colon and rectal cancer mostly produce the same symptoms like gas, stomach pain, fatigue, weakness, bloody and dark coloured stool, constipation and diarrhea. The approach used by the doctor to diagnose both these types of cancers is also the same. A colonoscopy is most likely to be carried out for diagnosing colon as well as rectal cancers. In colonoscopy, a thin, long and flexible tube is used by the doctor to see the inside of the rectum and colon. If areas that could have cancer are identified, the doctor can remove small samples called biopsies from those regions and test them. Some people even have small non-cancerous growths called polyps in their colon, which may also need to be removed before they cause any problem.

Differences Between Colon and Rectal Cancers Based on Treatment

Treatment for Colon Cancer: When colon cancer is diagnosed, the doctor usually starts the treatment with a surgery. This operation is called colectomy and is done to remove a section of the colon. The doctors mostly reconnect the separated sections of the colon after the surgery and the patient begins to have normal bowel movements again. But in cases where this does not happen, another operation called a colostomy needs to be performed. In colostomy, the doctor connects the colon to a hole in the abdomen, called an ostomy, and a bag is attached to the ostomy to collect bowel secretions. A patient, whose colon cancer has spread to the lymph nodes or affects a thick section of the colon, needs to undergo chemotherapy to kill the cancerous cells.

Treatment for Rectal Cancer: Surgery is considered to be the best treatment for rectal cancer where the doctor can fully remove the tumor form the rectum. The patient suffering from rectal cancer may also need to undergo radiation therapy and chemotherapy for shrinking a tumor before surgery, or killing the remaining cancer cells after surgery. During a rectal cancer surgery, the doctor tries to cut out the cancer affected tissue without removing the anal sphincter muscle, which controls the opening and closing of the anus during bowel movements. But sometimes a rectal tumor is so close to the anal sphincter that the muscle cannot be saved. In such cases, the doctor needs to conduct a colostomy. The need for a colostomy after colon cancer surgery is quite rare, but 1 in 8 people with rectal cancer require an ostomy.


So, hopefully now it’s clear that both colon and rectum are different parts of the intestine; hence making them 2 different and separate types of cancers with different treatments. The only thing similar between colon and rectal cancers is the similarity of the symptoms and the diagnosis procedure, which can confuse some people into thinking that both these cancers are one and same.

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Team PainAssist
Team PainAssist
Written, Edited or Reviewed By: Team PainAssist, Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:February 8, 2019

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