Colorectal cancer: causes, diagnosis, and treatment

Written by: Dr Ganesh Sivaji
Edited by: Lauren Dempsey

Colorectal cancer is one of the most common cancers affecting both men and women in the UK. Thankfully, if diagnosed early, it can be treated and beaten. In our most recent online interview, Dr Ganesh Sivaji highlights the warning signs that shouldn't be ignored and should be examined by a doctor to make an early diagnosis. The Harrogate-based consultant gastroenterologist details the options available and other factors that make someone a high-risk patient. 


How does colorectal cancer affect one's day-to-day life?

Cancer of any kind can be a life-changing event, not only for the patient but for the extended family and loved ones as well. Cancer can impact a patient's mood, cause anxiety, and raise questions about longevity and the future of the patient and their loved one. Colorectal cancer causes particular problems such as:

  • profound blood loss in the stool, resulting in anaemia, tiredness, and fatigue
  • bowel obstruction, causing abdominal pain
  • loss of appetite, leading to unintentional weight loss and weakness.


What causes colorectal cancer?

There are several theories as to why cancer develops in the colon, a family history of colorectal cancer and the presence of previous colon polyps are the most significant. When identifying high-risk patients, The British Society of Gastroenterology (BSG) Guidelines take these two into consideration. That’s to say if there is a long family history of colorectal cancer in the first-degree relatives, or if there has been a previous history of polyps, either in first-degree relatives or in the patient himself or herself then it is deemed that they have a higher risk of colorectal cancer.  

There are certain familiar conditions that can predispose to colorectal cancer and there are some screening tests available for the same. But again, having a detailed family history is a big step forward in this aspect. There are other colon conditions, like inflammatory bowel disease which can predispose to colon cancer as well. 

How is it diagnosed and treated?

Like any other cancer, having a high index of suspicion and awareness of the red flag symptoms and presentations can lead to an early diagnosis. The key symptoms include new-onset abdominal pain, presence of a lump in the tummy, a change in the bowel pattern from what is normal, seeing blood in the stool, and having unintentional weight loss. If one is experiencing any of these symptoms, it is absolutely vital to seek the expert help of a gastroenterologist

When you see a gastroenterologist, like me, the things that we do include a basic blood test, which will give us some clues. However, the gold standard is doing a camera investigation of the large bowel. In technical terms, this is called a colonoscopy and it is a fibreoptic instrument inserted through your back passage and aims to go all the way around your large bowel to see if there is any reason for your symptoms. The main intention is to identify and rule out the possibility of cancer. 

What are the treatment options and potential side effects?

Once cancer has been diagnosed, the patient needs to go through what is called a staging process. This identifies or sees if the cancer has moved outside of the colonic wall and whether it has spread to the lower lymph glands or to the rest of the body, in medical terms called metastasis.  To do this, we ask the patient to have a CT scan of the whole body. We then discuss the colonoscopy findings, the patient-related findings, and the CT scan findings in a multidisciplinary team (MDT) meeting to decide the best way forward. 

Treatment options could include a combination of colorectal surgery, for which a colorectal surgeon is needed, to remove either part of the bowel or all of it, depending on the extent of cancer. Chemotherapy, using medications to shrink the size of the cancer, and for this, we would need an oncologist, a cancer specialist. Chemotherapy comes with its own side effects because they are a very strong medication. Patients usually complain about hair loss, being extremely tired, lethargic, and weak. It is important to note that in the last 5 to 10 years, chemotherapy has developed very quickly, and the medication that is available these days has much fewer side effects than what it had 10 years ago. Patients are able to cope with these chemotherapy drugs much better than they were before. 

Chemotherapy is used either before or after the surgery to get better results or in unfortunate situations where there has been an extensive spread of the cancer and it is used to curb or slow down the cancer rather than treat it, to buy the patient valuable time to enjoy with their loved ones. Sometimes radiotherapy is also used to shrink the cancer, in particular when colon cancer leads to bowel obstruction.

What is important from a patient perspective to know about colorectal cancer?

From about the age of 55, the risk of developing colorectal cancer increases. For this reason, the government has initiated and been running the national bowel cancer screening programme. Initially, it was targeted for patients above the age of 65, but now it has been reduced to increase the uptake, diagnose patients quickly, and treat cancer before it gets out of hand. Patients should be aware of the red flag symptoms and understand that treating colorectal cancer needs the expert help of a specialist, and in this case, a gastroenterologist, who will then help provide the help of other specialists like a colorectal surgeon, radiologist, or oncologist.

If you are experiencing any of the red flag symptoms mentioned above or would like to book a consultation with Dr Ganesh Sivaji for another reason, you can do so directly from his Top Doctors profile. 

By Dr Ganesh Sivaji

Dr Ganesh Sivaji is a highly-experienced consultant gastroenterologist based in Harrogate, England. He diagnoses and treats a wide range of gastrointestinal and hepatological diseases. His areas of expertise include inflammatory bowel disease, indigestion and reflux disease, liver diseases, bowel cancer management, Barrett's disease and endoscopy.

In 1995, Dr Sivaji graduated from Tamil Nadu Dr MGR Med University in Chennai, India. He then continued studies and went on to obtain his Doctor of Medicine degree in 1998.

Dr Sivaji has been practising as a consultant in the UK since 2002, and now holds private consultancy positions in Harrogate at both BMI The Duchy Hospital and the Harrogate Hospital. Since 2010, he has also been operating at the Harrogate and District NHS Foundation.

In addition to his consultancy work, Dr Sivaji takes a keen interest in education and training; he is a Royal Collage International examiner and the training program director for Yorkshire. He is also a member of the BMA.

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