Rectal Cancer

1 What is Rectal Cancer?

Rectal cancer is a type of cancer that begins in the cells lining the interior of rectum, the end segment of your large intestine.

Rectal cancer together with colon cancer is called colorectal cancer. Rectal cancer develops from precancerous polyps, which can be detected before they turn into rectal cancer or have recently turned so.

As with other cancer, early diagnosis ensures a better outcome. Treatment often comprises of surgery to eliminate the affected portion. However, other options such as chemotherapy and radiation therapy can also be used.

2 Symptoms

You may experience no symptoms of rectal cancer if your cancer is in early stage. When present, the signs and symptoms of colon cancer include:

  • Any persistent change in bowel habit such as diarrhea or constipation or a change in the stool consistency
  • Bleeding from rectum
  • Abdominal pain or gas that lasts longer than normal
  • Feeling of incomplete evacuation
  • Weakness or tiredness
  • Unintended loss of weight

When to see a doctor?

Any persistent change in bowel habit can be suspected for rectal cancer. See your doctor if you observe blood in your stool or any other signs that linger.

You may also consult your doctor about the appropriate time and frequency to start rectal cancer screenings. Screening should start as you turn 50.

3 Causes

The exact cause of rectal cancer is not well understood in most cases. Mutations in the DNA of cells in the rectum causes “out-of-control” growth and multiplication of these cells.

These abnormal cells, unlike the normal ones, live longer and accumulate to form a mass of cancerous cells. These abnormal cells can affect nearby tissues or may affect distant body parts.

Some cancer-causing mutations can transfer from one generation to another but cases of cancer due to such inherited genes are less common. In fact, these genetic mutations when combined with environmental factors such as smoking can significantly your risk of rectal cancer.

The most common forms of inherited colon cancer syndromes are:

  • Hereditary nonpolyposis colorectal cancer (HNPCC): Also called Lynch syndrome, this condition boosts your chances of developing colon cancer and other cancers. HNPCC can cause colon cancer before a person reaches 50.
  • Familial adenomatous polyposis (FAP): People with FAP may develop thousands of polyps in the interior surface of colon and rectum. If left untreated, FAP may result in colon cancer before a person reaches 40.

Both these genetic disorders are detectable through genetic testing. Consult your doctor if you are considering a genetic test.

Recent studies have shed light on the link between a high-fat, low-fiber diet (typical western diet) and colon cancer. The exact cause and effect relationship is yet to be determined.

4 Making a Diagnosis

Making a diagnosis of rectal cancer is done by performing several tests.

Screening for Colon Cancer

Colon cancer screenings may help in early detection of colon cancer, thereby improving the chances of recovery. Talk to your doctor about when to start colon cancer screening.

How to prepare yourself for the visit?

Getting prepared for the visit can optimize the therapy and help make the visit more fruitful. List out all the symptoms. Write down your key medical information.  Write down the names of all your medications, vitamins or supplements.

Ask a friend or a family member to accompany you during the visit. Make a list of the questions to ask your doctor. Some typical questions can be:

  • What could be possible causes of my symptoms?
  • What are the tests that I need?
  • What are my treatment options?
  • Do I have rectal cancer? If so, what’s the stage?
  • Is my condition related to heredity?
  • Do I need follow-up testing?
  • Are there any food restrictions?

What your doctor wants to know?

A clear talk with your doctor can optimize the therapy and improve the outcomes. Prepare yourself to answer some essential questions from your doctor. Your doctor might ask you typical questions like:

  • When did you start noticing your symptoms and how severe are they?
  • Do your symptoms appear continuously or occasionally?
  • Do you have a personal or a family history of colon cancer or colon polyps?
  • Does anyone in your family have other cancers of the digestive tract, the uterus, ovaries or the bladder?
  • Do you smoke and drink? If yes, how often?

To further the diagnosis, your doctor may recommend:

  • Colonoscopy: Your doctor can visually examine the interior of your colon and rectum by using a long, flexible camera-containing tube (colonoscope). Any tissues likely to be cancerous can be scraped off and analyzed further (biopsies).
  • Blood tests: There are no markers of colon cancer in the blood but blood can be tested to have an overview of your general health through tests for liver and kidney function.

Staging Colon Cancer

Staging helps to determine the extent of cancer, treatment approach and outcome of the therapy. The stages of colon cancer are:

  • Stage I: The cancer is limited to the colon wall or rectum. Only the superficial layers are affected.
  • Stage II: The cancer is still limited to the colon wall or rectum but has affected deeper layers into or through the wall of the colon or rectum. Surrounding lymph nodes are not affected.
  • Stage III: The surrounding lymph nodes are affected by the cancer.
  • Stage IV: The cancer has spread to distant body parts such as liver or lung.

5 Treatment

Treatment options for rectal cancer are selected by analyzing factors like the size, stage and location of your cancer, your overall health, and your preferences.

Treatment options include:

Surgery

Surgery is aimed at removing the cancer and a small portion of the nearby tissues. Small cancers that are limited to the surface of the rectum need no incisions and the surgery is simple while in cases of larger cancers, an entire rectum or a part of it is removed by surgery.

After surgery, the ends of intestine can be reconnected to allow normal evacuation or the end of intestine can be joined to an opening made in the abdominal wall (colostomy) from where the intestinal waste moves out and is collected in a bag outside the body.

The various surgical approaches employed while removing rectal cancer include:

  • Endoscopic surgery: An endoscopic surgery utilizes an endoscope (a long, thin camera containing tube attached with special tools) to visualize and then remove the cancer. Cancers present on the surface of rectum can be removed by cutting tools or lasers. In a specialized type of endoscopic surgery called endomicrosurgery, a powerful microscope rapidly analyzes tissue samples and assures surgery has completely removed the cancer
  • Laparoscopic surgery: This is also called minimally invasive surgery because this surgery creates numerous small incisions in your abdomen instead of making a large incision. Through these incisions, your surgeon can insert special tools and a camera to visualize and then remove the cancer. This surgery can shorten your hospital stay while offering a quicker recovery.
  • Robot-assisted minimally invasive surgery: This surgery is carried out by using small tools attached to a robotic arm. Your surgeon then guides and controls the arm to perform surgery while sitting in front of a computer. Robotic surgery allows surgeon to work more efficiently in a small area and also gives surgeon a clear view of the area where the surgery is being carried out.
  • Traditional surgery: It is an open procedure in which the surgeon removes the cancer through an incision made in your abdomen.

Chemoradiotherapy or radiochemotherapy

It is the combination of chemotherapy and radiation therapy. Chemotherapy uses chemicals to destroy cancer cells while radiation therapy uses ionizing radiations like X-rays, to kill cancer cells.

In some cases, a combination may be used to amplify the effectiveness of each. This approach is beneficial for recurrent colon cancers.

Chemoradiotherapy may be used before surgery to destroy the cancer as much as possible so that it can be removed more easily by surgery. Chemotherapy and radiation therapy can be used separately or combined with surgery.

6 Risks and Complications

Your risk for rectal cancer is increased if you:

  • Are over 50,
  • Are African-American,
  • Have had colorectal cancer or polyps,
  • Have inflammatory bowel diseases such as ulcerative colitis and Crohn's disease,
  • Have genetic syndromes like familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer (Lynch syndrome),
  • Have a family history of colon cancer,
  • Follow a low-fiber, high-fat diet,
  • Do not exercise regularly,
  • Have diabetes,
  • Are obese,
  • Smoke and drink,
  • Have received radiation therapy for other cancer.
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