Condition	Definition	Prevalence	Average age at symptomatic presentation	Average age at diagnosis	When to start screening	Screening interval	Recommending organizations	Comments
Attenuated familial adenomatous polyposis4,5	10 to 99 synchronous advanced adenomas	Unknown	52 years	58 years (range = 29 to 81 years); 69% of patients studied developed CRC by 80 years of age	Late teens to mid-20s	Colonoscopy every one to two years	ACG, NCCN	Proximal colonic distribution necessitates colonoscopy for all screening
Familial adenomatous polyposis4,6,7	≥ 100 colorectal adenomas	Approximately three cases per 100,000	36 years (range = 4 to 72 years)	39 years; risk of developing CRC by 45 years of age is 87%	Sigmoidoscopy starting at 10 to 12 years of age	Sigmoidoscopy every one to two years until polyp is found, then colonoscopy	ACG, NCCN	If colectomy is delayed more than one year after polyps are found, colonoscopy should be performed annually
Hereditary nonpolyposis colorectal cancer6,8,9	May be defined clinically or by presence of one of five DNA mismatch repair genes	Unknown but estimated to be one in 440	< 45 years	45 years; lifetime risk of CRC is 75% to 80%	25 years of age or five years earlier than the first cancer case in the family, whichever comes first	Colonoscopy every one to two years	International Collaborative Group on HNPCC; Revised Bethesda Guidelines for HNPCC (National Cancer Institute); European Hereditary Tumour Group	Simplified clinical screening criteria: Patients with a first-degree relative with CRC diagnosed before 50 years of age Presence of synchronous and/or metachronous CRC or other HNPCC-associated tumors (e.g., endometrial or gastric)
Inflammatory bowel disease10–13	Ulcerative colitis or Crohn disease with colonic involvement	Crohn disease: 11 per 100,000 Ulcerative colitis: 12 per 100,000	Crohn disease: 30 years Ulcerative colitis: 35 years	40 to 50 years; 4% to 5% lifetime risk of CRC	Colonoscopy eight to 10 years after the onset of symptoms	Every one to three years	Crohn's & Colitis Foundation; American Cancer Society Colorectal Cancer Advisory group	Annual surveillance colonoscopy in patients with primary sclerosing cholangitis
MUTYH-associated polyposis4,6,9,14	Typically < 100 colorectal adenomas	Less than one in 10,000	Unknown	48 years; risk of CRC is 19% by 50 years of age and 43% by 60 years of age	Colonoscopy beginning in late teens to mid-20s	One to two years	ACG, NCCN	First described in 2002
Peutz-Jeghers syndrome4,6	Hamartomatous polyposis	One in 50,000 to 200,000	Polyp growth begins in the first decade of life, but patients typically do not develop symptoms until the second or third decade	Unknown	Esophagogastroduodenoscopy, colonoscopy, and video capsule endoscopy should begin at eight years of age and, if negative, be repeated every three years	If polyps, colonoscopy every three years If no polyps, wait until 18 years of age, then colonoscopy every three years; repeat video capsule endoscopy every three years	ACG, NCCN	Intussusception is a common complication typically occurring in individuals younger than 20 years
Sessile serrated adenomatous polyposis15,16	At least five serrated polyps proximal to the sigmoid colon, two of which are greater than 10 mm in diameter Any number of serrated polyps occurring proximal to the sigmoid colon in an individual who has a first-degree relative with serrated polyposis More than 20 serrated polyps of any size distributed throughout the colon	Unknown but estimated to be one in 2,000 to 3,000	44 to 62 years	44 to 62 years; 25% to 70% have CRC at the time of diagnosis	Colonoscopy in first-degree relatives of patients with sessile serrated adenomatous polyposis syndrome beginning at 40 years of age or 10 years younger than the age at diagnosis of the youngest affected relative	Annual colonoscopy with intent to clear proximal colon of all serrated lesions Colonoscopy every five years in first-degree relatives	ACG	Surgery is indicated when CRC is diagnosed or polyps cannot be controlled endoscopically Following resection, endoscopic surveillance of any residual colon and rectum should be performed every six to 12 months