Colorectal cancer (or cancer of the large bowel) is the second leading cause of cancer-related death in the western world. The average person has a 1 in 20 chance of developing colorectal cancer throughout their lifetime. This translates into around 30,000 new cases in the UK each year. Although colorectal cancer can occur at any age, more than 90% is found in people over the age of 40, the risk increases with age and most people diagnosed in their 60’s or 70’s.
What are the symptoms?
Diagnosing colorectal cancer is a challenge. Early cancers or pre-cancerous lesions known as polyps are often asymptomatic, whilst many cancers present with symptoms which are attributed to common conditions such as piles or a stomach bug. General symptoms which should alert suspicion include; rectal bleeding, an alteration in bowel habit, abdominal pain and weight loss, however patients with the following are considered to be at particularly high risk of having a cancer and should be referred to a specialist colorectal surgeon without delay;
- Rectal bleeding and a change in bowels towards looser/more frequent stools for 6 weeks in those aged 40 or over
- Rectal bleeding without anal symptoms for 6 weeks in those 60 or over
- A change in bowels towards looser/more frequent stools for 6 weeks in those aged 60 or over
- Patients with a mass in the right side of their abdomen
- Men of any age with iron deficiency anaemia (haemaglobin <11g/100mls)
- Non-menstruating women with iron deficiency anaemia (haemoglobin <10g/100mls)
Is colorectal cancer preventable?
Most colorectal cancers develop from a single cell and become a non cancerous (benign) growth known as a polyp. This grows slowly and eventually become a cancer. The challenge for doctors is to identify cancers in their early or pre-cancerous stage. Polyps appear as projections inside the colon and can usually be removed by colonoscopy. To help with early detection, the government has introduced a screening program which offers the chance of undergoing a telescopic examination of the bowel (flexible sigmoidoscopy) at the age of 55 and a test looking for microscopic traces of blood in the stool for those between the ages of 60 and 70. If you have not automatically been contacted speak with your GP to ensure that you are included in the national screening programm.
Dietary modification may reduce the risk of developing colorectal cancer although the precise benefit remains unclear. Increasing fibre intake by eating more fruits, vegetables and whole grains and reducing your intake of fats and refined foods will certainly reduce the overall risk of developing all forms of cancer in addition to reducing the risk of heart disease, diverticular disease, constipation and piles. Some studies have demonstrated a slightly reduced risk of developing polyps in groups taking aspirin or calcium supplements but again the impact in the population is unclear.
What is the difference between benign and cancerous growths?
A cancer cell is unique in that it can spread into other organs and begin to grow there (rather like a seedling from a plant), benign growths cannot do this and benign cells are unable to survive if they break away from the tissue that they arrose from. Cancers can also spread by direct growth of the tumour into nearby organs such as the abdominal wall, other loops of bowel, the bladder and prostate (in men) or uterus and vagina (in women). Distant spread when cells break away from the main tumour, is known as metastases and may occur by cells passing through the blood stream or the lymph glands. The commonest sites of distant spread for colorectal cancer are the liver and the lungs.
How are cancers of the colon and rectum treated?
The treatment of these cancers has undergone major changes over the last few years. Although the mainstay of therapy remains surgery the introduction of newer chemotherapy drugs and the benefits of radiotherapy mean that many patients who would have had a limited life expectancy in the past can be offered the chance of a cure. Cancers occurring in the rectum (the lower 15cms of bowel) may be greatly reduced in size by chemotherapy and radiotherapy before surgery is undertaken (this is known as “neo-adjuvant” therapy) and in some cases may be erradicated completely. Newer surgical techniques have dramatically reduced the risk of the cancer returning in many cases, and reduced the likelihood of needing a permanent stoma.
The advent of laparoscopic colorectal surgery means that patients may avoid large abdominal incisions, recover from surgery far quicker and have less post-operative pain. Operations to remove metastasis from the liver and lungs, although not suitable for everyone, are now commonplace and achieve long term survival in up to a third of people. Techniques such as Radiofrequency Ablation (RFA) can also be used to destroy metastasis in a day case setting in some suitable patients. Following surgery newer chemotherapy drugs have been shown to improve survival considerably, particularly in those with cancer that has spread to the lymph glands (this is known as adjuvant therapy). Due to wide array of treatment options your case will be discussed by your surgeon at a multidisciplinary meeting (MDM) which consists of a variety of other doctors such as oncologists, radiologists, pathologists and other surgeons who all specialise in cancer therapy. Following general agreement in this meeting, your surgeon will explain your further management to you in detail.
What is “staging”?
Before any treatment plan is decided, you will undergo a variety of investigations including blood tests, a colonoscopy, a CT scan of your chest and abdomen (and an MRI scan if you have a rectal cancer). This allows your surgeon to evaluate the extent of the tumour and tailor treatment as appropriate. After surgery, the cancer is sent to a pathologist who will examine it using microscopic techniques to see;
- How far it has grown into the bowel wall
- If it has spread into nearby lymph nodes
- The degree of differentiation (how similar to normal cells the cancer cells of this particular tumour are).
Estimates of long-term survival relate directly to the stage of the disease. A patient in whom the caner is limited to the bowel wall and does not involve the lymph nodes, have an excellent outlook. Those in which the cancer has spread to other areas or involves the lymph nodes have an increased risk that the cancer may return however the chance for cure is significantly improved by additional treatment such as chemotherapy, radiotherapy or even further surgery.
What is follow-up?
After surgery patients under go a special follow up to make sure that, should the cancer return, it is identified early giving the best chance of cure. If a cancer does recur they tend to do so within the first 2 years following surgery however, follow up is traditionally continued for 5 years before cure can be confidently declared. A standard follow up protocol would be:
- A colonoscopy 6 months after surgery of this had not been performed before surgery
- Further colonoscopy at 5 years depending on the findings of the previous colonoscopy
- CT scan of chest, abdomen and pelvis 1, 2 and 5 years after surgery
- Carcinoembryonic antigen (CEA) blood tests every 6 months
- Unlimited access to colorectal specialist nurses for any concerns
Although an intensive follow up programme has been shown to improve outcomes, some patients will develop recurrent cancer between visits to the surgeon or oncologist and any new symptoms or worries should be discussed with them or one of the specialist nurses as soon as they occur.
Follow up after liver resection surgery
Some patients require surgery to remove an area of colorectal cancer that has spread to their liver. Patients generally do very well after this procedure but require a slightly different follow up, an example of this would be:
- CT scan 4 weeks after surgery
- CT scan of chest, abdomen and pelvis and blood test measuring liver function, blood count and CEA every 6 months for the first 3 years after surgery and annually for the next 2 years