Colorectal Cancer : Symptoms, Cause, Treatment, Survival Rate, Screening Test, Prevention

Colorectal Cancer

What is colorectal cancer?

Colorectal Cancer is the occurrence of two cancers as names suggest colon cancer and rectal cancer. Rectal cancer originates in the rectum, and colon cancer in the intestine. According to the World Health Organization (WHO) and the US CDC, it is the second most common cancer worldwide after lung cancer. Most cases of colorectal cancer begin as small, cancer-free clumps of cells called adenomatous polyps. Over time, some of these polyps turn into colorectal cancer.

Polyps are often small, and they do not show any signs of occurrence. That’s why doctors suggest regular screening tests. These screening tests identify polyps before they become colon cancer and help prevent colorectal cancer.


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Types of Colorectal Cancer

There are two types of colorectal cancer

  1. Colon cancer: Cancer of the large intestine – the lower part of your digestive system.
  2. Rectal Cancer: Cancer of the end of the colon several inches long.

Both of these are often referred to as “colorectal cancer.”


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Symptoms of colorectal cancer

Colorectal cancer does not show any specific symptoms especially in the early stages. Here are the symptoms which can be:-

  • Going to the toilet frequently.
  • Diarrhea
  • Constipation
  • Feeling the urge to go to the toilet even after passing a bowel movement.
  • Blood in stool.
  • stomach ache
  • Feeling bloated (this can happen even if it has been a long time after eating)
  • Vomiting
  • Exhaustion
  • Frequent weight loss.
  • Feeling of a lump in your abdomen or back by the doctor.
  • High deficiency in iron, in men or women after menopause.

Causes of Colorectal Cancer

Experts say they are not entirely sure why colorectal cancer occurs. However, several risk factors for colorectal cancer have been identified over the years.

Risk Factors for Colorectal Cancer

A risk factor can increase a person’s chances of developing a disease.

The risk factors for colorectal cancer are –

  • Getting Older – The older you are, the greater the risk.
  • Too much animal protein in the diet.
  • Diet rich in saturated fats.
  • Food that has very little fiber content.
  • Diet, contains a lot of calories.
  • Drinking too much alcohol
  • Women who have had breast cancer, ovarian cancer, or uterine cancer.
  • Family history of colorectal cancer
  • patients with ulcerative colitis
  • Overweight / Obesity Smoking – This study found that smoking plays a significant role in increasing the risk of colorectal cancer and death.
  • Being physically lethargic.
  • Polyps in the colon or rectum.
  • Untreated polyps can eventually become cancerous.
  • Crohn’s disease or irritable bowel disease increases the risk of developing colorectal cancer.

Colorectal Cancer Screening Test

How is colorectal cancer diagnosed? With early diagnosis of colorectal cancer, it can be treated well. The doctor will start by getting information about your medical and family history. They will also do a physical exam. The doctor can determine the presence of lumps or polyps by pressing on your abdomen or by examining the rectum.

1. Blood Test

Your doctor may do certain blood tests to find out the cause of your symptoms. Although there is no blood test that specifically checks for colorectal cancer, liver function. Other diseases and disorders can be ruled out by a complete blood count (CBC) test.

2. Colonoscopy

Colonoscopy uses a long tube attached to a camera to examine your colon. Through this procedure, the doctor inspects your colon and rectum and notes for abnormalities. A colonoscopy enables your doctor to remove tissue from abnormal areas so they can send them to a laboratory for analysis.

3. X-rays

Your doctor may use a radioactive liquid called barium for X-rays. The doctor will inject this liquid into the intestines through an enema. After the liquid passes into the intestines, it coats the lining of the colon and provides an outline so that an X-ray can be taken.

4. CT Scan

A CT scan gives the doctor a detailed image of your colon. In the case of colorectal cancer, another CT scan called a virtual colonoscopy is performed.

Stages of Colorectal Cancer

Doctors can use staging to find out how far your cancer has spread. It is very important for the doctor to know the stage of your cancer so that they can design the best treatment plan for you and give an estimate of your recovery time. Stage 1  is the earliest stage and this stage can progress to stage-4, which is the last stage. 

The following are the stages of colorectal cancer :-

Stage I  In stage one disease enters the membrane around the colon or rectum but still has not spread to the walls of the organs.

Stage 2 cancer has spread to the walls of the colon or rectum, but still does not affect the lymph glands (lymph nodes) or surrounding tissue.

Stage 3 The cancer has spread to the lymph glands, but has not yet reached other parts of the body. Typically, one to three lymph nodes are involved at this stage.

Stage 4 This is the last stage and  has spread to other body parts, such as the liver or lungs

Colorectal Cancer Prevention

There is a lot we can do to reduce the chances of developing colorectal cancer –

  • Regular checkups – especially if you have had colorectal cancer in the past, are over 60 years old, have a family history of this type of cancer, or have Crohn’s disease. Some experts say that testing should be started after the age of 50.
  • Nutrition – Make sure your diet is rich in fiber, fruits, vegetables, and good-quality carbohydrates. Limit or stop the consumption of red meat and processed meats. Consume good quality fats, such as avocado, olive oil, fish oil, and nuts, in place of saturated fat. However, this study found that although vegetarians have a lower risk of developing cancer, the risk of developing colorectal cancer is higher in these individuals than in meat eaters.
  • Exercise – Exercise regularly. The risk of developing colorectal cancer can be reduced by doing a little exercise every day.
  • Body weight – Keep your body weight balanced. Being overweight or obese increases a person’s risk of developing other cancers, including colorectal cancer.

Colorectal Cancer Treatment

The treatment of colorectal cancer depends on various factors. For example, your overall health status and the stage of colorectal cancer will help your doctor create an effective treatment plan.

  • Surgery

In the early stages of colorectal cancer, possibly the polyps can be surgically removed. The chances of surgery being successful depends on the attachment of polyp to the surface of the intestine.

If your cancer has spread to the walls of the intestine, your surgeon may need to remove a part of the colon or rectum along with the lymph nodes around it. 

During the surgery healthy parts of the colon are reattached and if it is not possible then they will do the colostomy.

In this, a special change is made in the structure of the abdominal wall to remove waste. A colostomy is usually temporary.

  • Chemotherapy

Chemotherapy uses drugs to destroy cancer cells if any cancer cells have been left out during the surgery.

This controls the growth of your tumor and provides relief from the symptoms of late-stage cancer.

  • Radiation

Radiation therapy uses a powerful beam of energy used in X-rays to identify and destroy cancer cells before and after surgery. This Radiation treatment is usually combined with chemotherapy.

  • Medicines

In September 2012, the Food and Drug Administration (FDA) of the United States approved the treatment of metastatic cancer, or end-stage colorectal cancer that if it does not respond to other types of available treatment and has spread to other parts of the body. 

Stivarga – approved Stivarga drug (regorafenib). This medicine blocks enzymes that promote the growth of cancer cells.

Colorectal Cancer Survival Rate

According to the prestigious website cancer.net that if this is diagnosed at a localized stage then the survival rate is 91%. If the cancer has become metastatic and spread to the local surrounding tissue or organs or the regional lymph nodes then 5 year survival rate is 72%. If this has reached the final stage and has spread to a distant part of the body then the 5 year survival rate is 14%.

Latest Research Update About Risk Factor of Colorectal Cancer

Research-Risk Factor-Colorectal Cancer-Ultra Processed Food Consumption

Latest study report published in the BMJ states that high consumption of total ultra processed food increases the risk of colorectal cancer among men and women. This will definitely support public health and limit some types of ultra processed foods for better health outcomes. Still further studies are required to understand the potential carcinogenesis of ultra-processed to colorectal cancer.

(Disclaimer: The information in this part of the article is for educational purposes only. All results must be clinically correlated with patient data in order to make an accurate diagnosis.)


References

  1. American Cancer Society [internet]. Atlanta (GA), USA; About Colorectal Cancer
  2. Granados-Romero JJ et al. Colorectal cancer: a review. Int J Res Med Sci. 2017 Nov;5(11):4667-4676
  3. B. Meyer, Chandrakanth Are. Current Status and Future Directions in Colorectal Cancer. December 2018, Volume 9, Issue 4 
  4. Patil PS, Saklani A, Gambhire P, Mehta S, Engineer R, De’Souza A, Chopra S, Bal M. Colorectal Cancer in India: An Audit from a Tertiary Center in a Low Prevalence Area. Indian J Surg Oncol. 2017 Dec;8(4):484-490. PMID: 29203978
  5. Indian Council of Medical Research. Consensus document for management of colorectal cancer. Division of Non Communicable Diseases; Delhi, India.

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