Colorectal cancer: Common doubts answered

Some factors that increase your risk of developing colorectal cancer are unavoidable and can’t be changed. Age is one of them.
Colorectal cancer is a cancer that starts in the rectum or colon.(iStock)
Colorectal cancer is a cancer that starts in the rectum or colon.(iStock)
Updated on Mar 25, 2020 10:42 AM IST
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ByBy Dr. Venkata Pradeep Babu Koyyala

Let’s look at some of the common questions that can strike patients and their attendants during the course of diagnosis and treatment of colorectal cancer.

What is colorectal cancer?

Colorectal cancer is a cancer that starts in the rectum or colon. Both organs are in the lower portion of your digestive system. The colon is also known as the large intestine. The rectum is at the end of the colon.

Dr. Venkata Pradeep Babu Koyyala
Dr. Venkata Pradeep Babu Koyyala

What are the symptoms of colorectal cancer?

Colorectal cancer may not present any symptoms, especially in the early stages. If you do experience symptoms during the early stages, they may include:



•Changes in stool colour

•Changes in stool shape, such as narrowed stool

•Blood in the stool

•Bleeding from the rectum

•Excessive gas

•Abdominal cramps

•Abdominal pain

If you notice any of these symptoms, consult a doctor and discuss getting a colon cancer screening. Please note that these symptoms are non-specific and can be caused by several other medical conditions. However, some investigations are necessary for your doctor to rule out colon cancer.

Who’s at risk for colorectal cancer?

There are some factors that may increase your risk of developing colorectal cancer:

Unavoidable risk factors

Some factors that increase your risk of developing colorectal cancer are unavoidable and can’t be changed. Age is one of them. Your chances of developing this cancer increase after you reach the age of 50.

•A prior history of colon polyps

•A prior history of bowel diseases

•A family history of colorectal cancer

•A genetic syndrome, such as familial adenomatous polyposis (FAP)

•Being of Eastern European Jewish or African descent

Avoidable risk factors

Other risk factors are avoidable. This means you can change them to decrease your risk of developing colorectal cancer. Avoidable risk factors include:

•Being overweight or obese


•Excessive consumption of alcohol

•Having type 2 diabetes

•Having a sedentary lifestyle

•Consuming a diet high in processed foods or red meats

How is colorectal cancer diagnosed?

An early diagnosis of colorectal cancer gives you the best chances of curing it.

Your doctor will start by getting information about your medical and family history. They’ll also perform a physical exam. They may press on your abdomen or perform a rectal exam to determine the presence of lumps or polyps.

Blood testing

Your doctor may run some blood tests to get a better idea of what’s causing your symptoms. Though there’s no blood test that specifically checks for colorectal cancer, there are some tumor markers like CEA levels that can give a clue. They may be useful in prognostication and during follow-up.


A colonoscopy involves the use of a long tube with a small, attached camera. This procedure allows your doctor to see inside your colon and rectum to check for anything unusual.

During a colonoscopy, your doctor can also remove tissues from abnormal areas. These tissue samples can then be sent to a laboratory for analysis.

CT scan

CT scans provide your doctor with a detailed image of your colon. When used in diagnosing colorectal cancer, another name for a CT scan is virtual colonoscopy.

What are the tests that help decide the type of treatment or chemotherapy in colon cancer?

•Whenever we are discussing about any cancer, two things are very important for your oncologist take treatment decisions and tell you about the prognosis.

•The first one is biopsy or histological diagnosis. In most of the cases, a colon cancer histology is Adeno carcinoma. However, there can be other histologies like lymphoma, sarcoma and Gastro intestinal stromal tumors (GIST). Sometimes, special tests are done over the same biopsy/ resected tissue for further information like IHC (Immunohistochemistry). The tissue of origin and histology are important parameters to decide the type and urgency of treatment.

•The second most important thing is the stage of disease. Usually many of the solid cancers have four stages, depending on the extent of their spread in the body, and so is colon cancer. If the cancer has originated in one organ and spread to other organs, it is referred to as stage 4 colon cancer. For example – A colon cancer spreading to liver.

Stage 3 or 4 symptoms

Symptoms are more noticeable in the late stages (stages 3 and 4). In addition to the above symptoms, you might experience:

•Excessive fatigue

•Unexplained weakness

•Unintentional weight loss

•Changes in your stool that last longer than a month

•Feeling like your bowels don’t completely empty


If colon cancer spreads to other parts of your body, you may also experience:

•Jaundice (yellow eyes and skin)

•Swelling in the hands or feet

•Breathing difficulties

•Chronic headaches

•Blurry vision

•Bone fractures

Does stage 4 cancer imply that nothing can be done?

•Many of the cancers, at least more than 1/3rd of all cancer diagnoses, occur in stage 4.

•Stage 4 cancer is not a death sentence.

•Almost all the advances in therapeutics we see are in stage 4 cancers.

•The best examples for these advances are seen for breast, lung and colon cancers.

•Many women survive years together with a good quality of life due to targeted therapies and efficient chemotherapies that are available today.

•Even in certain stage 4 colon cancers with liver limited spread, both organs can be operated and treated upon with curative intent.

Know more about colorectal cancer here.

This article has been written by Dr. Venkata Pradeep Babu Koyyala, MD (Gen.Med) DNB (Medical Oncology) Consultant, Medical Oncology, Rajiv Gandhi Cancer Institute and Research Centre, New Delhi.

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