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Colorectal Cancer: Types, Treatment, Symptoms, and Causes

Colorectal Cancer: Types, Treatment, Symptoms, and Causes

Colorectal cancer is a really painful form of cancer that leaves the patient in extreme pain and discomfort. According to estimates after excluding skin cancer, colorectal cancer is the third most prevalent form of cancer that affects both male and female population equally. In the States, colorectal cancer is the third most fatal type of cancer that claims the lives of men and women. Since the death toll due to colorectal cancer in India is also high, it’s high time that we make ourselves aware of this particular form of cancer and possibly prevent it in the early stages.

Colorectal Cancer

What is Colorectal Cancer?

Colorectal cancer refers to the type of cancer that affects the colon or the rectum of the patient. It is also called bowel cancer as it is related to the motion in the bowel movements. Colon cancer is yet another term used to describe colorectal cancer. Colorectal cancer usually starts with the development of irregularities in the cell lining of the rectum and the colon leading to the formation of tumours. There are basically two types of tumours namely benign and cancerous. Benign tumours are non-harmful unless their position is blocking the function of any other body part. Cancerous tumours, on the other hand, are very dangerous as it spreads across your body and leads to complications that might lead to eventual death.

In the beginning stages of colorectal cancer, colorectal polyps begin to form. Colorectal polyps are potentially non-cancerous growths that form in your colon as you age. If left untreated, colorectal polyps have the ability to become cancerous. Therefore, its very important that you remove precancerous polyps as early as possible to keep yourself away from colorectal cancer. Colorectal polyps can take several forms, adenomatous polyps are the non-cancerous growth that begins in your colon or rectum and develops into cancer if left untreated. In most cases the size of the polyps will be too small to start showing immediate symptoms, that’s why doctors emphasize the importance of regular colon check as you start to age or starts feeling the growths in the rectum or the colon.

Types of Colorectal Cancer:

In a broad sense colon cancer occurs with the growth of tumours in the in the colon and cancer which starts with the growth of cancerous tumours in the rectum are called rectal cancer. When classified under the type of cancer that can affect your intestine there are mainly six types:

1. Colorectal Adenocarcinoma:

Colorectal adenocarcinoma is one of the most prevalent forms of colorectal cancer. It constitutes to about 95% of all the colorectal cancer cases. In the gastrointestinal tract, polyps can sometimes become adenomas which can easily become cancerous. That’s the reason why it is extremely important to remove polyps by doing a regular colonoscopy.

There are mainly two subtypes of adenocarcinoma:

Mucinous Adenocarcinoma: Characterised by its structure containing 60 % mucus, this type of cancer is very aggressive as the mucus allows it to spread more rapidly. They account to a total of 10-15 % of all colon and rectal cancers.

Signet ring cell Adenocarcinoma: Characterized by its peculiar structure under a microscope, this type of cancer is very aggressive by nature. Extremely rare, this type of adenocarcinoma is very difficult to treat.

2. Gastrointestinal Carcinoid Tumors:

Neuroendocrine tumours are the kind of tumours that affect the nerve cells. Sometimes these kinds of tumours may spread to the lungs or the gastrointestinal tract causing colorectal cancer. It’s very rare and contributes to about 1 % of all the colorectal cancers registered.

3. Metastatic Colorectal Cancer:

Metastatic colorectal cancer is the result of tumour cells in the rectum or the column breaking away and spreading to other parts of the body through the lymphatic system or through the bloodstream. Once they accumulate at a new location, they start to spread even faster. This type of cancer that is caused due to the breaking away of tumour cells from the colorectal cancer tumours are called metastatic colorectal cancer.

4. Primary Colorectal Lymphomas:

This type of cancer develops in the lymphocyte cells in the lymphatic system. Hailed as Non-Hodgkin lymphoma this type of cancer affects the white blood cells that are responsible for fighting infection. Since the network of the lymphatic system is extensive, this form of cancer can spread extremely fast. Even though it can spread quite fast, primary colorectal lymphoma only contributes to around 0.5 % of all cases of colorectal cancer.

5. Gastrointestinal Stromal Tumors:

Commonly known as GIST’s these are very rare kind of tumours that grow in the inner linings of the gastrointestinal tract. It specifically targets cells called the interstitial cells of Cajal. Mostly occurring in the stomach, it sometimes metastasizes to the small intestine and the third commonplace for gastrointestinal stromal tumours to occur are the rectum. Considered as fatal sarcoma, the rarity of this type of cancer often leads it to become undetected and dangerous.

6. Leiomyosarcomas:

In simple terms, leiomyosarcoma is cancer that affects the smooth muscle tissues. The digestive system extends to the colon and rectum where about 3 different layers of smooth muscles aid in the waste guidance system. This type of colorectal cancer is one of the rarest, contributing to just about .1% of the entire reported cases.

Colorectal Cancer Symptoms:

Once the precancerous polyps are formed the body will start showing some symptoms. However, the size and position of the polyps determine the ease of diagnosis. Many other non-cancerous issues can show the same symptoms as colorectal cancer. Conditions such as haemorrhoids and IBS are certain conditions that show identical symptoms to that of colorectal cancer.

Some of the most common symptoms of colorectal cancer are :

  • Considerable change in bowel movements.
  • Constipation or diarrhoea characterized by a feeling of bowel not being completely empty after excretion.
  • Blood in stool either in bright red colour or dark shaded.
  • Changes in the shape of the stool. Sometimes becoming narrower than usual or broken in format.
  • Abdomen discomfort including sudden gas induced pain, bloated feeling or cramps.
  • Considerable loss of weight in the individual.
  • Fatigue and a constant feeling of tiredness.
  • Anaemia due to unexplainable reasons leading to pale skin and low RBC count.

Causes and Risk Factors for Colorectal Cancer:

Colorectal cancer can be caused by a wide range of reasons. Even though the condition can be quite surprising to most patients, there are several factors that we can avoid to reduce the risk of being affected by colorectal cancer. We should understand the fact that normal functioning of the cells is sometimes affected with mutations in the DNA causing the cell to malfunction and become cancerous. In the below section we will be discussing the different causes and also the risk factors involved in colorectal cancer.

Causes of Colorectal Cancer:

  • Inherited Gene Disorders: Inherited gene disorders are genetic disorders that are passed down through heredity. Parents with faulty genes can easily pass down the condition to their offsprings. The percentage of colorectal cancer victims suffering due to inherited gene disorders are however very low.There are mainly two types of inherited genetic disorders that can cause colorectal cancer. Lynch Syndrome, also known as HNPCC (Hereditary nonpolyposis colorectal cancer) is one of the conditions that can be inherited and can cause cancer. Another common inherited genetic condition that can cause cancer is Familial Adenomatous Polyposis (FAP). This rare genetic condition can cause the springing of over a thousand polyps in the rectum and the colon and can put the patient at risk of colorectal cancer by the age of 40.
  • Diet: Diet plays a very important role in the overall health of a person. It’s imperative that diet has to play as a crucial factor in the development of colorectal cancer as it is a form of cancer that affects the digestive tract. The kind of food we take in has a major role to play in the process of excretion and digestion. There is much research that shows that western diet mainly composing of high-fat derivatives and low fibre content can be a big cause for colorectal cancer. People who have been living in a geographic area where the diet is high in fibre moves to a region where the diet is mainly comprised of fat, the chances of being affected with colorectal cancer increases.

Risk Factors for Colorectal Cancer:

A risk factor is basically anything that can increase your risk of being affected by a particular disease or condition. Colorectal cancer has very few hereditary causes and therefore it’s important that you understand that the risk factors for colorectal cancer basically depends on your overall lifestyle and eating habits. Some of the leading risk factors for colorectal cancer are:

  • Age: The frequency of colorectal cancer affecting the young population is fairly low compared to the adult population above 50. Colorectal cancer is often seen after the age of 50 and therefore age becomes a risk factor for the disease.
  • Race: Race of a person is also a leading risk factor for the development of colorectal cancer. Research has shown that people from the African-American origin have a higher chance of developing colorectal cancer as they age.
  • Intestine malfunctions or Inflations: In certain cases, if the individual is affected by certain rare conditions such as Crohn’s Disease or ulcerative colitis can be contributing factors for colon cancer.
  • Sedentary Lifestyle: A sedentary person has a higher chance of being affected with colorectal cancer. Even though it might come as a surprise, but exercise can help you in keeping your colon healthy.
  • Diabetes: The low insulin resistance associated with diabetes can be a leading risk factor that might lead to colorectal cancer.
  • Obesity: As you already know diet is a very important factor for the development of colorectal cancer. Studies have shown that obese people are more likely to be affected with colorectal cancer when compared with people of normal weight.
  • Smoking and Drinking: Smoking and drinking alcohol are also contributing risk factors for the development of colorectal cancer.

Treatments for Colorectal Cancer:

Colorectal cancer is a painful condition that can affect anyone beyond a certain age. The location of the cancer tumours makes it really hard for the patients to get along with their earlier lifestyle. The are various methods of treatment that are used in the treatment of colorectal cancer. The most widely used methods for the treatment of colorectal cancer are listed below.

  • Surgery: Surgery to remove the tumour cells caused due to colorectal cancer is a viable method of treatment used worldwide. In surgical treatments, the patient is generally referred to a surgical oncologist who is a cancer specialist.
  • Radiation Therapy: Radiation therapy is also used as a treatment option for colorectal cancer. In radiation therapy, the patient is subjected to controlled doses of radiation which will help in the destruction of the malignant cancer cells. Radiation therapy is very powerful and can have serious implication on the patients overall health. Good care is required if someone is undergoing radiation therapy.
  • Chemotherapy: Chemotherapy is one of the most effective methods in treating cancer in the colon and the rectum. In chemotherapy, medicines are used to directly attack and mitigate the cancer cells and prevent them from spreading.
  • Targeted Therapy: Targeted therapy is yet another treatment method for colorectal cancer that has been receiving a lot of attention lately. In targeted therapy, a certain specific set of genes and tissue environment along with certain proteins are targeted to stop the spreading of cancer and to rescue the healthy cells from cancer.

There are various subdivisions in these above-mentioned treatment plans and the best possible method of treatment is selected by your oncologist based on the stage and the characteristic of cancer that is affecting your body.

Also Read:  Stomach Cancer: Symptoms, Causes, And Prevention

How to Screen for Colorectal Cancer?

Screening is a medical procedure done in order to make sure that there is no cancer affecting you. The benefit of conducting regular screening is that the chances of getting cancer can be reduced if you are able to identify early symptom for the same. Since conditions like colorectal cancer can take a long time to start showing symptoms it’s important that you conduct regular screening to reduce the risk.

The main tests that are used to screen for colorectal cancer are given below:

  • Colonoscopy: Colonoscopy is an invasive medical procedure which allows the doctor to see the insides of your colon and your rectum to identify polyps or tumours. The patient will be sedated for the procedure.
  • CT Colonography: Computerised tomography is a non-invasive medical procedure that helps the doctor to get a precise picture of your colon and rectum and identify if there are any polyps or tumours present.
  • Sigmoidoscopy: Sigmoidoscopy is a medical procedure in which the doctor inserts a lighted tube into the rectum of the patient to identify tumours or polyps.
  • Fecal Occult Blood Test and Fecal Immunochemical Test: These are two medical procedures that are used to identify if there are traces of blood in your stool as this is one of the earliest symptoms for colorectal cancer. Since there are many other factors that could lead to this condition, the test has to be done at regular intervals to confirm.
  • Double contrast barium enema: For some patients who might have problems in conducting a regular colonoscopy, a barium mixed enema is given that will help in highlighting the rectum and colon during a regular x-ray. This method is used if colonoscopy cannot be carried out.

What is the Medicine for Colorectal Cancer?

There are various medications that are available for the treatment of colorectal cancer. The precise type and dosage of medication can only be prescribed by a certified practitioner after analyzing the symptoms, stage, and size of the tumour cells affecting you due to cancer. Some of the popular drugs that are used in the treatment of colorectal cancer are:

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How Common is Colorectal Cancer?

Here are some key statistical insights that will help you in understanding the severity of the presence of colorectal cancer in the general population.

  • In the United States, Colorectal Cancer is the third most common form of cancer affecting the general population.
  • By the month of February in the year 2018, the number of people affected by colon cancer was 97,220 and the number of people affected by rectal cancer was 43,030.
  • According to studies the risk of a male being affected by colorectal cancer is 1 out of 22 which is about 4.49%.
  • The lifetime risk of a female to develop colorectal cancer is 1 out of 24 which is about 4.15%.
  • There has been a significant reduction in the amount of death caused due to colorectal cancer over the years thanks to the better medical care and patients taking early screening seriously.

Colorectal cancer is a very painful condition in which the patient and their loved ones suffers equally. It’s important that you do everything in your power to ensure that you follow up with regular check-ups with your doctor to avoid any complications in the future.


Now that you have obtained a fair idea as to how the dangers of colorectal cancer can affect you there might be some more questions that must be lingering in your head. In the below section we will try and answer some of the frequently asked questions about colorectal cancer.

1. How do I know if I have colorectal cancer?

There are various symptoms that can help you identify colorectal cancer. It’s important that you do regular checkups with your doctor to check for polyps in your colon or rectum.

2. What is the difference between colon cancer and rectal cancer?

Both of them belong to the class of colorectal cancer and are caused due to adenoid polyps. The difference is that colon cancer occurs in the colon and rectal cancer occurs in the rectum.

3. Can smoking cause colorectal cancer?

Smoking is a very potent carcinogen intake mechanism, it is highly risky to smoke if you are trying to avoid colorectal cancer.

4. Can Colorectal Cancer be cured?

Yes. colorectal cancer can be managed if detected in the early stages. It’s highly recommended that you do regular checkups including a colonoscopy to ensure that any signs of colorectal cancer can be nipped in the bud.

Also Read:  Lung Cancer: Causes, Symptoms, And Prevention

News on Colorectal Cancer

Use Of Nsaid Can Help Reduce The Risk For Colorectal Cancer: Findings From New German Research

– 27th Nov 2018

In an interesting turn of events in an ongoing research by German scientists, it was found that the use of non-steroidal anti-inflammatory drugs can significantly reduce the risk of colorectal cancer. The results of the study were published in the Journal of National Cancer Institute. Non-steroidal anti-inflammatory drugs are basically the format in which drugs like aspirin comes under. It may come as a surprise to many to know that using an aspirin can significantly reduce the risk for colorectal cancer.

The research was conducted on a test group of 2444 patients who were recently diagnosed with colorectal cancer and the results were compared with data collected from 3130 healthy patients to understand how the use of NSAID can affect the development of colorectal cancer in the patients. The study mainly focused on the molecular pathways taken by the drugs to better understand its effects on MSI-High BRAF and KRAS mutated colorectal cancer in order to get a better picture on how the use of NSAID’s like aspirin can reduce the chances of mutation in the cells that line the colon and rectum of the patients.

The researchers believe that the research could be the starting point for future research that aims at understanding the effect of various foreign medications can have on the healthy prognosis of cancer in various positions in the body. In the US adults who come under the age gap of 50 – 59 to regularly use low doses of NSAID’s like aspirin to reduce the risk for colorectal cancer. This initiative taken by the US Preventative Services Task Forces further asserts the positive effects NSAID could have on the prognosis of colorectal cancer.


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