Colorectal Cancers Explained

Estimated Reading Time: 7 minutes

Ramsay Health Care Consultant Colorectal and General Surgeon, Mr Triantafyllos Doulias, has been explaining colorectal cancer; the difference between colonic and rectal cancer, symptoms, screening, and curability.  

Colonic cancer is the 2nd leading cause of cancer related deaths globally. In 2020 more than 1.9 million new cases and about 930,000 colorectal cancer related deaths were estimated to have occurred worldwide (1,2).

Bowel cancer is strongly related to age, the highest rates in elderly people, with the risk of getting it rising dramatically from the age of 50-55 years (1,2,3). However, optimistically, in 2019 Cancer Research UK have reported that bowel cancer mortality rates have decreased by around 11% in the UK – the main reason for this being the effective screening programme (1).

Are colonic and rectal cancer the same?

Colon and rectal cancers are not the same. They vary on the location, the symptomatology, the diagnosis, along with the oncological and the surgical treatment.

The rectum is the last part of the large bowel with a length of about 12-15 cm. The rectum is located in a contained area in the pelvis, and it lacks the outer protective layer called serosa. Therefore rectal cancer can metastasise easier, is staged differently, and the disease can be more advanced due to close proximity to the surrounding organs in the pelvis.


Colorectal cancer often has no warning symptoms in the early stages. The colonic and the rectal cancer share mainly the same symptoms.

Common symptoms include:

  • Changes in bowel habits such as diarrhoea, constipation, erratic bowel movements
  • Blood in the stool (rectal bleeding), bright red or mixed with the stools
  • Persistent abdominal bloating or pain
  • Unexplained rapid weight loss 
  • Constant feeling of tiredness and lack of energy, even after resting
  • Iron deficiency anaemia due to chronic bleeding PR
  • Fatigue, weakness, and paleness.

Screening for colorectal cancer

Screening is the best way to detect colorectal cancer early which increases the chances of complete cure and improved quality of life. The bowel cancer screening programmes in the UK use home test called ‘the Faecal Immunochemical Test (FIT)’ which detects blood in the stools.

In England from April 2021, there is a gradual reduction in the age range for bowel screening. This will be phased over the next four years to include people aged 50-59. In Scotland, screening starts from age 50 whereas in Wales bowel cancer screening starts from the age of 51 to the age of 74. In Northern Ireland people over the age of 60 are invited to take part in screening. The individuals are invited to take part in screening every two years until the age of 75.

Most people’s screening result shows they do not need any further tests. 98 out of 100 tests will be negative which means that no blood cells were found in the sample at the time taken the test. The negative result does not guarantee the no presence of bowel cancer since 1 in 10 patients with negative FIT test, the result is false negative.

Increased awareness of the symptoms of bowel cancer is very important for early detection. 2 out of 100 people who complete the FIT test will have positive test therefore they will need to proceed to an endoscopic investigation i.e. flexible sigmoidoscopy or a colonoscopy. In elderly comorbid patients a CT colonography could be a good alternative to an endoscopic procedure.

Is colorectal cancer curable?

Depending on the stage and the type of the colorectal cancer at the time of the diagnosis the 5-year survival rate varies. Individuals diagnosed with colorectal cancer at its earliest stage have more than 90% survival 5 years post diagnosis. If the cancer was found in a polyp fully removed during a colonoscopy, then this might be the only treatment required with frequent endoscopic follow ups.

For colorectal cancers at the early stages of the disease a minimally invasive surgery is the gold standard treatment. When the tumour is locally advanced (involving surrounding structures) then the management involves a combination of oncology and surgical treatment. The type of the oncology treatment is determined on the location (rectum or colon) and the stage of the disease during the initial assessment. Perforated or obstructed tumours may benefit from a two-stage surgical technique depending on the experience of the operating surgeon at the time of the emergency admission to the hospital.

Following the surgical resection, the need of further treatment is dependent on a number of factors including the post-operation report, the pre-operative stage of the disease, and a decision from a multidisciplinary team discussion.

Follow Up Plan

An intensive follow-up plan allows for earlier detection of recurrences in patients at risk (5,6). A clinical examination is advised every 6 months for 3 years and every 12 months at years 4 and 5 after surgery (5,6).

A colonoscopy must be carried out at year 1 and every 3-5 years thereafter cancers [III, B] and a CT scan of the chest and abdomen every 12 months for the first 3 years can be considered in patients who are at higher risk of occurrence. (5,6) 


Bowel cancer incidence statistics | Cancer Research UK

April – Bowel Cancer Awareness Month (

Colorectal cancer (

Issaka et al, Gastroenterology 2023;165:1280–1291. AGA Clinical Practice Update on Risk Stratification for Colorectal Cancer Screening and Post-Polypectomy Surveillance: Expert Review

Northern Cancer Alliance Colorectal Stratified Follow Up Clinical Review and Surveillance Guidelines

G. Argilés et al, Localised colon cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Annals of Oncology, 2020

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