History and exam

Key diagnostic factors

common

family history

Having a first-degree relative with sporadic colorectal cancer is associated with an increased risk of large adenomas (odds ratio 2.5, 95% CI 1.1 to 5.4) and high-risk adenomas (size ≥1 cm and/or villous component; odds ratio 2.6, 95% CI 1.3 to 5.1).[17]

People with relatives affected by colorectal cancer or polyps in more than two generations are at increased risk of having adenomas compared with people with relatives affected by colorectal cancer or polyps in one generation.[8] 

Other diagnostic factors

uncommon

rectal bleeding

May be present but is an unusual symptom of colonic polyps.

mucus discharge

This is an unusual presenting symptom.

weight loss

This is an unusual presenting symptom.

tenesmus

The sensation in the rectum postdefecation that it was incompletely emptied may be present, but is an unusual symptom in colonic polyps.

change in bowel habit

May also be relevant, particularly if associated with urgency.

symptoms and signs of anemia

Symptoms and signs of iron-deficiency anemia (e.g., fatigue, pallor) can indicate polyps, although this is not a specific sign and is usually absent.

Risk factors

strong

increasing age

Polyp prevalence increases with age.[8]

Among average-risk adults, 3.4% of females and 5.2% of males have large polyps on screening colonoscopy at ages 40 to 49 years.[9] The comparable figures at ages ≥80 years are 7.3% and 11.0%, respectively. 

family history of colorectal cancer or colorectal polyps

Having a first-degree relative with sporadic colorectal cancer is associated with an increased risk of large adenomas (odds ratio 2.5, 95% CI 1.1 to 5.4) and high-risk adenomas (size ≥1 cm and/or villous component; odds ratio 2.6, 95% CI 1.3 to 5.1).[17]

People with relatives affected by colorectal cancer or polyps in more than two generations are at increased risk of having adenomas compared with people with relatives affected by colorectal cancer or polyps in one generation.[8] 

previous history of polyps

The incidence of polyps at surveillance increases when multiple or advanced polyps have been identified at an initial colonoscopy.[18][19]

weak

male sex

Men have a 1.5 to 3 times greater relative risk compared with women.[7][8][9]

acromegaly

People with acromegaly have a two- to threefold increased risk of hyperplastic polyps and colon adenomas compared with people without acromegaly.[20] Screening colonoscopy is recommended on diagnosis of acromegaly, and every 5 to 10 years thereafter.[21]

Use of this content is subject to our disclaimer