What is the lifetime risk of colorectal cancer?

Colorectal cancer is the third commonest cancer in the United Kingdom (after lung & breast cancers). About 5% of the UK population will develop colorectal cancer (20% will develop colorectal adenomatous polyps). There is thus a 1 in 20 lifetime risk of developing colorectal cancer. The disease kills about 20 000 people a year in the UK.

Colorectal cancer affects men and women roughly equally. The risk is greatly increased in patients with family history of familial polyposis or hereditary non polyposis colorectal cancer. The risk is also moderately increased in the presence of family history of colorectal cancer or polyps and the presence of past medical history of breast, uterine or ovarian cancer. Risk is also higher for people with a history of long standing extensive ulcerative colitis & Crohn's colitis.

FAQ

I had some bowel symptoms, should I be screened for colorectal cancer

Screening is for asymptomatic people. Once you have symptoms you need immediate appropriate investigations (not waiting for screening as outlined on this page e.g. until you become 50)

Am I at higher than average risk of developing colorectal cancer?

1. Have you had colorectal cancer or polyps in the past?
2. Do you suffer from - long term -inflammatory bowel disease (Ulcerative Colitis or Crohn's disease of the colon)?
3. Did any member of your family have colorectal cancer or polyps?

If the answer is yes to any of these then you are at high risk, especially if affected family member is a first-degree relative (parent, sibling, or child), and the younger the age the cancer or polyp first diagnosed.

I am 83 years old and in good health, should I be screened for colorectal cancer?

The answer is probably yes, but..

The current British Society of Gastroenterology Guidelines suggest that patients above the age of 70 should not be screened (East Kent NHS trust local guidelines extend this to 75). The situation in the USA is more fluid. I have always disagreed with the 70 age limit, as I regularly operate on patients with colorectal cancer (with curative intent) in their late eighties and early nineties and I can not see the rationale for stopping screening at 70 years. This may represent a biased view on my part. However, there is strong evidence in the literature and from my own data at QEQM that patients above 75 do well with major colorectal resection. The relevant question, is actually whether the benefits of colorectal cancer screening may outweigh the risks of colonoscopy in patients aged 70 years and older. KO & Sonnenberg tried to answer this question (Gastroenterology 2005;129:1163-1170,1342-1344). They found that the risks outweigh the benefits in certain groups of patients (under the assumption that colorectal cancer screening were unlikely to benefit those whose life expectancy is less than 5 years). I simplified their categories as follows

1. Patients 75 - 85 years old with poor health

2. Patients 85 - 90 years with average or poor health

3. Patients aged 90 to 95 years in good health

These ages may be lowered by up to 5 years in men because of their naturally lower life expectancy

I feel that these results can be read also in the following manner "patients aged 70 - 85 in good health may be candidates for screening, provided they understand the increased risks of colonoscopy at this age"

Screening: Introduction

There is now sufficient evidence in the literature showing that screening for colorectal cancer does indeed reduce mortality from the disease. Colonoscopy is the current favourite tool in screening, especially in the defined higher risk groups (family history, FAP, HNPCC & previous cancer or polyps). FOB & flexible sigmoidoscopy may have a role in population screening.

A word of caution (aimed at patients)

What follows is the current consensus regarding screening guidelines (British & American guidelines). As with any guidelines, these are sometimes modified in a particular patient. There are many situations where the surgeon (or gastroenterologist) will choose to adopt more or less aggressive screening. Examples include incomplete examinations, inadequate views (because of poor bowel preparation), patients with unknown family history (e.g. adopted) and also depending on the results of any previous tissue removed. Local resources, patient preference and anxieties may have to be taken into consideration. If in doubt discuss these issues with your GP or contact me.

Screening Methods:

1. Colonoscopy

2. Flexible sigmoidoscopy

3. Faecal occult blood testing (FOB)

4. CT Colonograpgy (Virtual colonoscopy)

Risk Stratification:

 

General population :

Average risk patients: If there is no family (or personal) history of bowel cancer or polyps, no history of ulcerative colitis or Crohn's disease then you are at average risk. The current American recommendations is to start screening at age 50. Patients are offered a choice between 1) yearly FOB (Faecal Occult Blood) 2) flexible sigmoidoscopy every 5 years 3) combined yearly FOB & 5 yearly flexible sigmoidoscopy 4) colonoscopy. Any positive test needs further investigations by colonoscopy

There is a strong consensus among gastroenterologists and surgeons that screening should be done using colonoscopy. In the future this may remain or may move to CT colonography (virtual colonoscopy)

Screening for average risk population remain unfunded by the NHS in the UK. It is also generally unfunded by insurance companies, but is available to self funded private patients.

High risk patients: This includes patients with Familial Adenomatous Polyposis (FAP) and those with Hereditary Non-Polyposis Colorectal Cancer (HNPCC) :

Familial Adenomatous Polyposis (FAP): This disease is autosomal dominant and almost 100% of individuals who have inherited the gene will develop colorectal cancer by age 40 (the youngest I have seen was 18 years old). The average age of appearance of polyps is 16 years. This means that genetic testing and looking for polyps by annual flexible sigmoidoscopy or colonoscopy should start at about 10-12 and not delayed beyond 14-15, to determine if they are expressing the genetic abnormality. Genetic testing should be considered in families of patients with FAP. Those diagnosed as FAP by genetic testing or by finding polyps (> 100) should have proctocolectomy in their early twenties.

A variant of FAP called attenuated APC (AAPC) is associated with smaller number of adenomas (usually 20–100), a tendency toward right-sided colonic adenomas, an age onset of colorectal cancer that is approximately 10 years later than for FAP. Although flexible sigmoidoscopy is adequate screening for most FAP families, colonoscopy should be used in those with AAPC, beginning in the late teens or early 20s, depending on the age of polyp expression in the family. Those diagnosed as attenuated FAP should also have proctocolectomy in their early twenties.

Persons >40 years old without the FAP phenotype (without polyps) and > 50 in attenuated FAP can be assumed to not be gene mutation carriers. Further intensive screening can be stopped.

Hereditary Non-Polyposis Colorectal Cancer (HNPCC): People with a genetic or clinical diagnosis of hereditary non polyposis colorectal cancer (HNPCC) or who are at increased risk for HNPCC should have colonoscopy every 1–2 years beginning at age 20–25 years, or 10 years earlier than the youngest age of colon cancer diagnosis in the family—whichever comes first. Genetic testing for HNPCC should be offered to first-degree relatives of persons with a known inherited mismatch repair (MMR) gene mutation.

Clinical Criteria for HNPCC
Amsterdam Criteria (for Clinical Identification of HNPCC)

At least 3 relatives with colorectal cancer plus all of the following:
One affected patient is a first-degree relative of the other two
Two or more successive generations affected
One or more affected relative had colorectal cancer diagnosis at age < 50 years
FAP excluded
Tumors verified by pathologic examination

Amsterdam II (Criteria for Clinical Identification of HNPCC, modified to take into account the increased occurrence of cancer other than of the colon and rectum)

At least 3 relatives with an HNPCC-associated cancer (colorectal cancer and cancer of the endometrium, small bowel, ureter, or renal
pelvis) plus all of the following:
One affected patient is a first-degree relative of the other two
Two or more successive generations affected
One or more affected relative received colorectal cancer diagnosis at age <50 years
FAP excluded in any case of colorectal cancer
Tumors verified by pathologic examination

Medium risk patients: This includes patients who had bowel cancer or polyps previously, long standing ulcerative or Crohn's colitis and / or some family history of bowel cancer (but not FAP OR HNPCC):

Previous colorectal cancer:

Patients with a history of previous colorectal cancer that has been resected with curative intent should have a colonoscopy around the time of initial diagnosis to rule out synchronous neoplasms. If this was not done or possible (e.g. colon was obstructed preoperatively), then colonoscopy should be performed within the next 6 months after surgery. If this or a complete preoperative examination was normal, subsequent colonoscopy should be done after 3 years, and then, if normal, every 5 years.

Previous colorectal polyps:

Patients who have had 1 or more adenomatous polyps removed at colonoscopy should be managed according to the findings on that colonoscopy. Patients who have had numerous adenomas, a malignant adenoma (with invasive cancer), a large sessile adenoma, or an incomplete colonoscopy should have a short interval follow-up colonoscopy based on clinical judgment.

Patients who have advanced or multiple adenomas (3 or more) should have their first follow-up colonoscopy in 3 years.

Patients who have 1 or 2 small (<1 cm) tubular adenomas should have their first follow- up colonoscopy at 5 years. The timing of the subsequent colonoscopy should depend on the pathology and number of adenomas detected at follow-up colonoscopy. For example, if the first follow-up colonoscopy is normal or only 1 or 2 small (<1 cm) tubular adenomas are found, the next colonoscopy can be in 5 years.

Family History of bowel cancer:

People with a first-degree relative (parent, sibling, or child) with colon cancer or adenomatous polyps diagnosed at age <60 years or 2 first degree relatives diagnosed with colorectal cancer at any age should be advised to have screening colonoscopy starting at age 40 years or 10 years younger than the earliest diagnosis in their family, whichever comes first, and repeated every 5 years

People with a first-degree relative with colon cancer or adenomatous polyp diagnosed at age >60 years or 2 second degree relatives with colorectal cancer should be advised to be screened as average risk persons, but beginning at age 40 years.

People with 1 second-degree relative (grandparent, aunt, or uncle) or third-degree relative (great-grandparent or cousin) with colorectal cancer should be advised to be screened as average risk persons.

Patients with IBD (Ulcerative Colitis & Crohn's Colitis): There is a higher risk of development of colorectal cancer in patients with long standing extensive (left sided or total colitis) IBD. The colorectal cancer risk is probably similar in Ulcerative & Crohn's colitis. It is generally agreed that regular screening should start 8-10 years after onset of symptoms (mainly to assess the extent of the disease & exclude dysplasia). Thereafter it is suggested that regular surveillance for patients with pan colitis should continue from year 10 (after onset) onwards and from year 15 onwards in left sided colitis.

Pan colitis 10-20 years 3 yearly
Pan colitis 21-30 years 2 yearly
Pan colitis After 30 years yearly

Looking for Dysplasia : biopsy specimens should be taken every 10 cm in all 4 quadrants. Additional biopsies should be taken from strictures and mass lesions other than pseudo polyps. Polyps that appear potentially dysplastic can be removed by polypectomy with biopsy of adjacent flat mucosa

Colitis in the presence of sclerosing cholangitis: Patients with sclerosing cholangitis have a much higher risk and should undergo yearly colonoscopy.

Screening in elderly patients (> 70 years)

The decision to recommend or pursue colorectal cancer screening in patients aged 70 and above should be individualized and should take into account a patient's life expectancy, co morbidity, and most importantly in my views patient's wishes, provided he or she is made aware of the risks of colonoscopy. The benefit above 80 - 85 years is questionable.

Currently our local NHS trust policy suggest that patients are not candidates above 75 years of age. Exceptions have to be fully documented.