Rectal Cancer: Symptoms, causes, diagnosis and treatment.

Rectal cancer is a type of cancer that develops in the rectum, the last six inches of the colon. Like other organs in the body, the rectum is vulnerable to many diseases and conditions, including cancer.


Rectal cancer is different from anal cancer, which refers to cancer in the area between the rectum and the outside of the body. The terms colon cancer and colorectal cancer are often used interchangeably, so much of the information you see about colon cancer applies to rectal cancer as well.

But rectal cancer is different from cancer that occurs higher up in the colon, especially when it comes to surgical treatment of the disease. An estimated 43,340 people died of rectal cancer in 2020 .

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In the early stages, rectal cancer usually has no symptoms. As the disease progresses, which can take years, symptoms of rectal cancer include :

  • Blood in the stool : It is usually bright red in color compared to blood in the stool, which is associated with cancers higher in the colon. The blood from these cancers can be dark red or black.
  • Digestive problems: persistent constipation, diarrhea, or other intestinal changes.
  • Softer stools: Stools that are described as "crayon" or liquid can occur when a swelling in the rectum blocks part of the canal.
  • Unexplained Weight Loss: Unintentional weight loss, defined as a loss of at least 5 percent of body weight over a period of six to 12 months, can be a symptom of rectal cancer.
  • Abdominal discomfort – can include pain, aches, or cramps.
  • General tiredness: You feel more tired than usual, even if you sleep well.
  • Anemia: When rectal cancer causes chronic mild bleeding, the first sign may be anemia or symptoms associated with anemia , such as dizziness, fatigue, or pale skin.

Causes and risk factors

Scientists don't know exactly what causes rectal cancer, but they do know what increases a person's risk of developing it. Risk factors for rectal cancer include :

  • Age: over 50 years old.
  • Family or personal history of colon cancer: Keep in mind that a person does not need to have a family history of colon cancer to have rectal cancer; it is most often diagnosed in people with no family history. 25 percent of colon cancers are believed to be genetically related .
  • Personal history of some types of colon polyps (small growths in the colon).
  • Smoking: current or past.

Screening and diagnosis

Several colon cancer detection methods are very effective in detecting rectal cancer. Colon and rectal cancer screenings include:

  • Colonoscopy: Colonoscopy allows a healthcare professional to obtain a detailed view of the colon using a colonoscope, a fiber optic tube that connects to a microscope camera that transmits live video to a monitor. The colonoscope is gently inserted into the anus and slowly into the colon, giving the healthcare professional a complete view of the rectum and colon.
  • Rigmoidoscopy. Similar to colonoscopy, sigmoidoscopy is performed with a flexible light tube with an attached camera, but it is limited to only the lower part of the colon.
  • Fecal occult blood test : A fecal occult blood test (FOBT) can detect blood in your stool that you cannot see with the naked eye, or confirm that it is actually blood in your stool that can have seen. You will be given a special collection kit for stool samples. Two similar tests are the stool immunochemical test (FIT) and the stool DNA test (Cologuard).

Adults who have an average risk of developing colon or rectal cancer are advised to begin the exam at the age of 45. Adults who are at higher risk of developing the disease may need to begin testing at an earlier age on the recommendation of their healthcare provider.

Remember, even if you don't experience any symptoms of rectal cancer, you should always follow your doctor's recommendations for screening. If the screening test shows suspicious results, a colon biopsy is done.

Colon biopsy can be done during a colonoscopy or surgery. During a colon biopsy, a small amount of rectal tissue is removed and then sent to a pathology lab to be examined for cancer.

If cancer is present, imaging tests such as computed tomography, magnetic resonance imaging (MRI), and endoscopic ultrasound can help determine the clinical stage that is critical in determining the course of treatment.

The surrounding lymph nodes are checked and can also be removed during surgery. More tests can be done to find out if the cancer has spread.

Illustration from Get Meds Info

Watch out

Treatment of rectal cancer will depend on the stage of the disease, as well as other factors, such as the specific location of the tumor or tumors and your general health.


In the early stages of rectal cancer, surgery may be the only treatment needed. There are several surgical techniques used to remove cancerous tissue from the rectum.

The type of surgery chosen depends on the general health of the patient, the stage of the rectal cancer, and the location of the tumor or tumors. For those who are unsuitable for surgery, radiation therapy may be an option, but it is generally not as effective.


Chemotherapy is used to treat rectal cancer when the tumor has spread to nearby lymph nodes and / or has invaded the intestinal wall. The body's organs are made up of cells that divide and multiply as the body needs them. When these cells continue to proliferate unnecessarily, the result is a mass or growth, also called a tumor.

Chemotherapy drugs kill these stubborn cells that multiply quickly. Chemotherapy for rectal cancer can be given before or after surgery and can also be given in combination with radiation therapy .

Radiation therapy

Another treatment option for rectal cancer, this type of therapy uses certain types of high-energy radiation to shrink tumors and destroy cancer cells. Radiation therapy works by damaging the cancer cell's DNA and causing it to die. It can also be given in combination with chemotherapy.


Regular colon cancer screenings are essential to prevent rectal cancer. Screening can detect precancerous growths before they potentially turn into cancer. Keep in mind that colon cancer takes years to develop, so routine screening tests can detect these changes long before they turn cancerous.

Avoiding risk factors for colon cancer can also lower your chances of developing the disease. It is important to eat a balanced diet , maintain a healthy weight, and stop smoking .

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