Colonic Polyps

Practice Essentials

Colonic polyps are slow-growing overgrowths of the colonic mucosa (see the image below) that carry a small risk (< 1%) of becoming malignant. However, because colonic polyps are highly prevalent in the general population (especially with increasing age), they confer an important predisposition to colon cancer and are therefore removed when detected.

View Image

Multiple large polyps in the colon. The polyp in the center of the image is situated on a stalk. (Endoscopic image).

See Benign or Malignant: Can You Identify These Colonic Lesions?, a Critical Images slideshow, to help identify the features of benign lesions as well as those with malignant potential.

Signs and symptoms

Most patients with colonic polyps are asymptomatic. In symptomatic patients, the most common presenting symptom is rectal bleeding; chronic bleeding from colonic polyps may cause iron deficiency anemia. Other symptoms of polyps include diarrhea or constipation, often with decreased stool caliber.

Occult blood in stools (detected by guaiac and antibody-based tests) may be found in a minority of patients with colonic polyps.

Distal rectal polyps can be detected by digital rectal examination. Otherwise, physical examination findings are typically normal.

Villous adenomas of the rectum and distal colon can occasionally manifest as a syndrome of severe diarrhea with massive fluid and electrolyte loss.

See Presentation for more detail.

Diagnosis

Stool occult blood test

A stool occult blood test can detect a proportion (20%-40%) of colonic polyps that are larger than 10 mm in diameter, but this test also suggests the presence of other causes of gastrointestinal blood loss.

Flexible sigmoidoscopy

Flexible sigmoidoscopy is a good screening test for colonic polyps and is the only procedure or imaging modality to be validated by studies that document a decrease in colorectal cancer mortality.^[1] However, this procedure does not examine the entire colon. Studies indicate that the majority of large adenomatous polyps in women will be missed by using flexible sigmoidoscopy alone.

Colonoscopy

Colonoscopy is the preferred test to detect colonic polyps, obtain biopsies, and/or perform endoscopic resection.^[2] Sensitivities for large colonic polyps in the 80%-90% range have been reported.

Although flexible sigmoidoscopy and stool tests for occult blood have been the mainstays of screening to prevent colon cancer, some clinicians now favor colonoscopy as a primary screening tool.^{[1, 3]}

Capsule endoscopy

An ingestible, camera-equipped capsule developed as a means of exploring the gastrointestinal tract received approval by the US Food and Drug Administration (FDA) in February 2014 for the detection of colon polyps in patents who have had an incomplete optical colonoscopy.^{[4, 5]}

Stool DNA

Tests have been developed that detect mutant, fragmented, and/or methylated deoxyribonucleic acid (DNA) from exfoliated colon tumor cells in stool. This test was approved by the FDA in August 2014.

See Workup for more detail.

Management

Polypectomy

In patients with a solitary or a few pedunculated or sessile polyps, colonoscopic removal can be performed concurrently with the search for other lesions.

Colonic resection

In the case of multiple intestinal polyps associated with familial adenomatous polyposis (FAP), colon resection remains the only feasible option (see the image below). Surgical resection may be advocated for large, sessile polyps that are difficult to remove endoscopically or for advanced colonic polyps that recur despite adequate initial endoscopic treatment.

View Image

Familial adenomatous polyposis, total colectomy specimen. The colonic mucosa is studded with innumerable sessile and small pedunculated polyps, which ....

Colonic resection is also advocated for patients with long-standing ulcerative colitis who have developed high-grade dysplasia or a dysplasia-associated lesion or mass (DALM).^[6]

Several surgical options should be discussed with the patient, including total colectomy, subtotal colectomy with rectal sparing, and segmental resection.

See Treatment and Medication for more detail.

• References

Background

Colonic polyps are slow-growing overgrowths of the colonic mucosa that carry a small risk (< 1%) of becoming malignant. However, because colonic polyps are highly prevalent in the general population (especially with increasing age), they confer an important predisposition to colon cancer and are therefore removed when detected.

Patients with isolated colonic polyps are usually asymptomatic but can experience overt or occult colonic bleeding. Colonic polyps can occur as part of inherited polyposis syndromes in which their number is greater and the risk for malignant progression is much higher compared to the risk associated with isolated colonic polyps.

In the context of clinical studies of chemoprevention, efforts are being directed at suppressing colonic polyp formation (eg, by the use of sulindac) and/or at preventing their progression to colon cancer (eg, by the use of aspirin).

• References

Pathophysiology

Colonic polyps, or adenomas, are benign epithelial neoplasms that arise from the epithelial cells lining the colon. Colonic polyps are traditionally divided into three groups, as follows: hyperplastic polyps, adenomas, and polyposis syndromes.

Hyperplastic polyps

Hyperplastic polyps comprise about 90% of all polyps and are benign protrusions. They are usually less than 0.5 cm in diameter. Hyperplastic polyps most commonly occur in the rectosigmoid region during adulthood.

Thought previously to be entirely clinically insignificant, hyperplastic polyps are now recognized to possess some malignant potential in the setting of hyperplastic polyposis syndrome. Patients who are affected have an occurrence of hyperplastic polyps proximal to the sigmoid colon, with (1) 5 or more serrated polyps proximal to the sigmoid colon with two or more that are larger than 10 mm in diameter, (2) a total of more than 20 polyps, or (3) a serrated polyp proximal to the sigmoid colon and a first-degree relative with the syndrome. The polyps in this syndrome may have adenomatous components; display a serrated, saw-tooth surface epithelium; and harbor BRAF mutations and methylation of specific target genes, including mismatch repair genes.^[7]

Adenomas

Adenomas comprise approximately 10% of all polyps. Most polyps (approximately 90%) are small, usually less than 1 cm in diameter, and have a small potential for malignancy. The remaining 10% of adenomas are larger than 1 cm and approach a 10% chance of containing invasive cancer.

Adenomas are traditionally divided by histology into three types, as follows: tubular, tubulovillous, and villous. Tubular adenomas are the most common of the three types and can be found anywhere in the colon. Villous adenomas most commonly occur in the rectal area; tend to be larger than the other two types; and tend to be nonpedunculated, velvety, or cauliflowerlike in appearance.

Villous adenomas are associated with the highest morbidity and mortality rates of all polyps. They can cause hypersecretory syndromes characterized by hypokalemia and profuse mucous discharge and can harbor carcinoma in situ or invasive carcinoma more frequently than other adenomas. Serrated adenomas exhibit a mix of adenomatous and hyperplastic features, with regions of saw-toothed, serrated-surface epithelium. They have malignant potential.

The risk of progression to carcinoma is related to both the size and the histology of the adenoma. Adenomas that are greater than 1 cm, contain a substantial (>25%) villous component, or have high-grade dysplasia are commonly referred to as advanced neoplasms and carry an increased cancer risk.

The shape or gross structure of the polyp is also clinically significant. Those polyps with a stalk are called pedunculated. Those polyps without a stalk are called sessile. (See the image below.) Sessile polyps are more concerning than large pedunculated polyps for two reasons. First, the pathway for migration of invasive cells from the tumor into submucosal structures is shorter. Second, the complete endoscopic removal is more challenging and more difficult to ascertain.

View Image

Multiple large polyps in the colon. The polyp in the center of the image is situated on a stalk. (Endoscopic image).

Some premalignant neoplasia are now recognized to be flat, rather than protuberant. Such nonpolypoid neoplasia are more common in the setting of chronic colitis and may be detected more readily by nontraditional endoscopic imaging methods, such as narrow-band width imaging or mucosal staining.

Polyposis syndromes

Polyposis syndromes are hereditary conditions that include familial adenomatous polyposis (FAP), hereditary nonpolyposis (a misnomer) colorectal cancer (HNPCC)/Lynch syndrome, Gardner syndrome, Turcot syndrome, MUTYH polyposis, Peutz-Jeghers syndrome, Cowden disease, familial juvenile polyposis, and hyperplastic polyposis. Serrated polyposis syndrome is manifested by (1) 5 or more serrated polyps proximal to the sigmoid colon with two or more at least 10 mm in size, (2) a serrated polyp proximal to the sigmoid colon in the context of a family history of serrated polyposis, or (3) 20 or more serrated polyps throughout the colon.

Progress has been made in understanding some of the genetic factors contributing to the development of these syndromes. Some of the syndromes have extraintestinal features that help differentiate one syndrome from the other. For example, FAP is best understood in terms of the genetic basis and subsequent pathological and genetic events leading to carcinoma.

Two other types of benign polyps are hamartomatous polyps, consisting of a mixture of normal tissues, and inflammatory polyps, which contain an inflammatory epithelial reaction and are typically found in the context of colitis seen in inflammatory bowel disease.

• References

Etiology

Environmental causes

Epidemiologic studies suggest that environmental causes contribute to the differences in colonic polyp incidence in geographically distinct populations, but the responsible factors have remained elusive.

Diet

Differences in the consumption of dietary fiber and antioxidants have been hypothesized to play a role in the development of colonic polyps, but these proposals have not been substantiated in recent studies. There is limited, circumstantial evidence that consumption of meat, fat, and alcohol may be risk factors. Conversely, consumption of calcium and folate may confer a modest protective effect, particularly in patients with a history of colonic polyps and low basal consumption levels.

Genetics

A number of polyposis syndromes have been described. These can be associated with specific extraintestinal manifestations as well as extraintestinal tumors.

Identification and characterization of the genetic factors leading to the various syndromes is progressing. Most of the mutant genes in these syndromes have been identified. Note the following:

• At the genetic level, familial adenomatous polyposis (FAP) is understood the best. This is an autosomal dominant disorder caused by truncating mutations in the adenomatous polyposis coli (APC) gene.
• Hereditary nonpolyposis colorectal cancer (HNPCC)/Lynch syndrome is an autosomal dominant disorder caused by mutations in the DNA mismatch repair proteins.
• Cowden disease is associated with mutations in the phosphatase and tensin homology on chromosome 10 (PTEN) protein phosphatase.
• MUTYH polyposis is a recessive disorder of base excision repair.

• References

Epidemiology

United States statistics

Population and autopsy studies suggest that about 30% of middle-aged or elderly individuals have colonic polyps. In comparison, the incidence of familial adenomatous polyposis (FAP) in the United States is one case for every 6580-8300 persons.

International statistics

Accurate comparison of colonic polyp incidence and prevalence among countries is difficult because of the differences in the methods used for detection. Colonic polyp prevalence in patients older than 60 years appears to vary substantially within and among countries, but it appears to be greater than 10% in most areas.

Race-, sex-, and age-related demographics

Race per se is not a major risk factor for colonic polyps. However, studies indicate that black individuals have a somewhat higher incidence and an earlier onset of colorectal carcinoma. Task force guidelines from the US Multi-Society Task Force on Colorectal Cancer as well as those from the American Gastroenterological Association (AGA) recommend beginning colorectal cancer screening in black persons at age 45 years, rather than the standard age of 50 years.^{[8, 9]}

Males appear to have a moderately higher colonic polyp incidence than females, with earlier onset observed in some studies.^[10]

Colonic polyps are strongly associated with increasing age (typically after age 40 y), but they can occur early in patients with polyposis syndromes. For example, colonic polyps can be detected in adolescents with familial adenomatous polyposis and in patients aged 20-40 years with hereditary nonpolyposis colorectal cancer (HNPCC).

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Prognosis

Colonic polyps are curable if removed. If not treated, the patient may develop complications, such as bleeding, and the condition may even be fatal if malignant transformation occurs.

Fortunately, colonic polyps grow slowly; cancer development is estimated to usually occur about 10 years after the formation of a small colonic polyp.

Hereditary nonpolyposis colorectal cancer (HNPCC) is an exception. Progression to cancer appears to be more rapid because of increased genetic instability in the lesion. Patients with HNPCC should undergo screening for colonic polyps at more frequent intervals (every 1-2 y) than patients at average risk.

Morbidity/mortality

Untreated, colonic polyps may progress to carcinoma over several years. Morbidity from colonic polyps is related to complications, such as bleeding, diarrhea, intestinal obstruction, and progression to cancer. Bleeding can be frank hematochezia but is often chronic and goes unnoticed by the patient. If uncompensated, intestinal blood loss can cause anemia, typically due to iron deficiency.

A study by Stryker et al suggests that the risk of cancer development from sporadic 1-cm colonic polyps is 8% at 10 years and 24% at 20 years.^[11] The risk of cancer development depends on the size of the polyp, villous histology, and its association with polyposis syndromes. In familial adenomatous polyposis (FAP), cancer inevitably develops 10-20 years after the initial appearance of colonic polyps.

A more recent review by Calderwood et al reported similar findings: An increased risk of colonic neoplasia was associated with villous features, high-grade dysplasia, and increased adenoma size, as well as the presence of three or more adenomas at baseline and/or serrated polyps in the proximal colon.^[12]

Complications

Complications of colonic polyps include bleeding, obstruction, diarrhea, and the development of cancer.

Complications of polypectomy are uncommon but include bleeding and, rarely, intestinal perforation.

• References

Patient Education

Patients with a family history of colonic polyps must be aware of the potential benefits of screening for colonic polyps

Patients with familial adenomatous polyposis (FAP) must be aware of the potential benefits of screening the upper gastrointestinal tract and screening family members, beginning at puberty, for the mutant APC gene. Screening is particularly important because of the inevitable development of colon cancer in affected individuals and the benefits associated with colonic resection.

Patients with hereditary nonpolyposis colorectal cancer (HNPCC)/Lynch syndrome should receive colon screening at frequent (1-2 y) intervals and are at risk for development of tumors at additional sites, including the uterus and the ovaries in female patients. These patients should consider screening for tumor development at such sites or prophylactic resection.

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History

History of present illness

Most patients with colonic polyps are asymptomatic. In symptomatic patients, the most common presenting symptom is rectal bleeding. Other symptoms include diarrhea or constipation, often with decreased stool caliber.

Villous adenomas of the rectum and the distal colon can occasionally manifest as a syndrome of severe diarrhea with massive fluid and electrolyte loss.

Chronic bleeding from colonic polyps may cause iron deficiency anemia.

Family history

Although colonic polyps are a disease of older individuals, a positive family history of polyposis should prompt referral for screening in younger individuals and, in some cases, at more frequent intervals. A common practice is to begin screening in a patient 5 years earlier than the age at which colonic polyps were diagnosed in a first-degree relative.

• References

Physical Examination

Distal rectal polyps can be detected by digital rectal examination. Otherwise, physical examination findings are typically normal.

Occult blood in stools (detected by guaiac and antibody-based tests) may be found in a minority of patients with colonic polyps. Although nonspecific, this finding should prompt a colon evaluation in most patients. Such evaluations have had similar yields of clinically significant findings whether the stool sample was obtained by digital rectal examination or was retrieved from spontaneously passed stools.

• References

Laboratory Studies

No laboratory test can determine definitively whether a given patient has a colonic polyp. A stool occult blood test can detect a fraction (20-40%) of colonic polyps that are larger than 10 mm in diameter but, it may also indicate other causes of gastrointestinal blood loss.

Anemia is not specific for colonic polyps but can be an indication of their presence.

A patient with a family history of familial adenomatous polyposis (FAP) may inherit a mutation in the APC gene. A blood test may detect this heterozygous state. In addition, because most APC mutations involve truncations of the protein, an in vitro protein truncation assay has been developed by Powell et al.^[13] This assay amplifies segments of APC messenger RNA (mRNA) and expresses the protein parts in vitro to readily detect the truncated products. A positive test only indicates susceptibility, not the actual presence of a colonic polyp.

Genetic testing of blood samples can also detect most cases of hereditary nonpolyposis colorectal cancer (HNPCC)/Lynch syndrome. Despite the name, patients with HNPCC have multiple polyps but much fewer than that seen in patients with the APC syndrome.

A potential precolonoscopy screening diagnostic marker for colorectal cancer is fecal glycolytic pyruvate kinase isoenzyme type M2 dimer (M2PK), but more investigation is needed.^[14] In a study comprising 20 patients with colorectal cancer, 20 with adenomatous colorectal polyps, and 20 normal subjects, fecal M2PK was the most sensitive and specific test for differentiating between colorectal cancer and adenomatous colorectal polyps and the control subjects. The study also assessed complete blood cell count, erythrocyte sedimentation rate, carcinoembryonic antigen, cancer antigen 19-9, fecal occult blood test, abdominopelvic ultrasonography, colonoscopy, and histopathology.^[14]

• References

Imaging Studies

Air contrast barium enema

An air contrast barium enema study can detect larger colonic polyps, but it can also miss smaller ones. This imaging modality has a low false-positive rate. In one study, air contrast barium enema detected only about 50% of colonic polyps larger than 1 cm in diameter.

Virtual colonoscopy

Virtual colonoscopy is performed by computed tomography (CT) scanning (or magnetic resonance imaging [MRI]), and it has shown promise in research studies, detecting more than 80% of large polyps. In a large, multicenter trial, however, a disappointing sensitivity of only 55% was obtained for colonic polyps 10 mm or larger in diameter. Another trial found a detection rate for CT scanning that was comparable to colonoscopy, although some methodological issues have been raised regarding this study.^[15]

Virtual colonoscopy is beginning to be performed for screening outside of research settings on limited numbers of patients. Relatively recent data from such screening procedures suggest that virtual colonoscopy results in the detection of far fewer polyps that are smaller than 1 centimeter in diameter than standard optical colonoscopy.^[16] Most small polyps have very benign characteristics at the time of removal and may be clinically insignificant. However, some are presumably precursors to advanced polyps. Therefore, their clinical significance, particularly for screening intervals, needs better definition.

The main drawback of virtual colonoscopy is that a second procedure, an optical colonoscopy, is required to remove the detected colonic polyps. Whether the radiation exposure from CT scanning may be significant is debated.^{[17, 18]}

In most methods, a thorough colon preparation is required. Methods are under development to label stool with barium meals, obviating the need for cathartic bowel prep.

• References

Procedures

Bowel cleansing

Adequate bowel cleansing is necessary prior to many procedures.

Several preparations are marketed for bowel cleansing (eg, polyethylene glycol 3350 [GoLYTELY, NuLYTELY, HalfLYTELY], magnesium citrate [Citroma], senna [X-Prep]) in preparing patients for gastrointestinal procedures, such as colonoscopy and barium x-ray studies. More recent experience suggests that splitting the preparation in half, with one portion taken the day before the procedure and the second portion taken early on the day of the procedure (eg, completed at least 4-6 h before the procedure) yields more effective cleansing of the right colon.

Bowel cleansing preparations may be used with various dietary modifications (eg, clear liquid diet the day before surgery or procedure) and are convenient to administer on an outpatient basis. Nonetheless, distaste for or discomfort from the preparation remains a complaint of some patients.

Colonoscopy

Colonoscopy is the preferred test to detect colonic polyps, obtain biopsies, and/or perform endoscopic resection of polyps.^[2] Sensitivities for large colonic polyps in the 80%-90% range have been reported.

Although flexible sigmoidoscopy and stool tests for occult blood have been the mainstays of screening to prevent colon cancer, some clinicians now favor colonoscopy as a primary screening tool.^{[1, 3]} Colonoscopy is the preferred tool in patients with defined polyposis or colorectal-cancer syndromes or in patients with a marked family history of colorectal cancer.

Flexible sigmoidoscopy

Flexible sigmoidoscopy is a good screening test and is the only procedure or imaging modality to be validated by studies that document a decrease in colorectal cancer mortality.^[3] However, this procedure does not examine the entire colon. Studies indicate that the majority of large adenomatous polyps in women will be missed by using flexible sigmoidoscopy alone.

Screening is usually begun at age 50 years in patients who are at an average risk.

Randomized controlled trials have documented a reduction in mortality from colon cancer in populations screened by flexible sigmoidoscopy. However, studies suggest that about 40% of high-risk proximal adenomas remain undetected when this procedure is used as the primary screening modality.

Capsule endoscopy

An ingestible, camera-equipped capsule developed as a means of exploring the gastrointestinal tract was approved by the FDA in 2014 for the detection of colon polyps in patents who have had an incomplete optical colonoscopy.^{[4, 5]} The device, a 12 x 33 mm capsule equipped with two miniature color video cameras, transmits images for approximately 10 hours. A study by Hagel et al demonstrated that the capsule had an 81.5% accuracy in detecting polyp carriers (per-patient analysis).^{[4, 19]}

Diagnostic rates for colon capsule endoscopy in the detection of colonic polyps and colorectal cancer have improved, and this modality also has a role in completing the evaluation of colonic pathology in patients in whom colonoscopy was incomplete.^[20]

Second-generation colon capsule endoscopy has a significantly higher sensitivity than the first-generation capsule in detecting colon polyps and is FDA approved as an option for colorectal cancer screening in those with a previous incomplete colonoscopy as well as in those with suspected lower gastrointestinal bleeding.^[21] However, thorough, rigorous bowel preparation is mandatory for optimal effectiveness.^[5]

This procedure is currently not endorsed for colon polyp screening. Van Gossum et al compared the efficacy of this device with that of colonoscopy in the detection of colorectal polyps, advanced adenomas, and cancer.^[22] In a study of 328 patients with known or suspected colonic disease, the authors found that capsule endoscopy had a sensitivity and specificity of 64% and 84%, respectively, for the detection of polyps that were 6 mm or more in size. Sensitivity and specificity for the detection of advanced adenomas were 73% and 79%, respectively. Capsule endoscopy detected 14 of 19 cancers that had been found using colonoscopy.

The investigators also determined that in patients with good or excellent colon cleanliness, capsule endoscopy's sensitivity was higher for all lesions than it was in individuals whose colon cleanliness was fair or poor. Van Gossum and colleagues concluded that in comparison with colonoscopy, capsule endoscopy has a low sensitivity for the detection of colonic lesions.

Stool DNA studies

Tests have been developed that detect mutant, fragmented, and/or methylated DNA from exfoliated colon tumor cells in stool. These tests have shown the ability to detect a substantial fraction of tumors in clinical trials^[23] but are expensive and appear to be less sensitive than colonoscopy.

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Histologic Findings and Staging

Adenomatous polyps are of three different histologic types, as follows: tubular, villous, and tubulovillous. Adenomatous polyps may show changes of dysplasia, which distinguish them from hyperplastic polyps. The most common benign polyp is hyperplastic.

Colonic polyps are typically benign. Colonic polyps that contain high-grade dysplasia or microinvasive cancer confined to the mucosa are often termed carcinoma in situ.

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Medical Care

Some studies have demonstrated that medical treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) decreases the number and the size of colonic polyps. However, NSAIDs, such as sulindac, do not prevent cancer development. These drugs do not yet constitute established therapies or chemopreventives for colonic polyps.

One study suggests that aspirin may be beneficial in reducing the incidence of recurrent colonic polyps, particularly advanced colonic polyps in select patients with a high risk of colon cancer (and coronary artery disease) and an acceptably low risk of gastrointestinal bleeding or hemorrhagic stroke.^[6]

Consultations

Obtain a Surgical consultation; this is critical in patients with multiple polyps, including patients with familial adenomatous polyposis (FAP). Explain and discuss the type and timing of surgery with the patient.

Diet and activity

A regular diet may be continued. The patient can consider calcium and folate supplements to decrease the risk of colonic polyp recurrence.

Activities may be maintained as tolerated.

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Surgical Care

Polypectomy

In the case of a solitary pedunculated polyp, colonoscopic removal can be performed concurrently with the search for other lesions.

Removal of a solitary colonic polyp is usually curative for that lesion. However, a complete colonoscopic examination should be performed because the finding of a single adenomatous polyp confers an increased risk for the development of others. The rate of colonic polyp recurrence (discovered at follow-up colonoscopy) at 1-year postpolypectomy is small, and recurrence may in fact represent missed synchronous lesions. Repeat colonoscopy at 3-12 months is sometimes advocated if there is substantial doubt whether a colonic polyp has been completely resected and/or contains high-grade dysplasia.^[24]

A systematic review and meta-analysis of the efficacy and safety of cold versus hot snare polypectomy for resecting small colorectal polyps found that cold snare polypectomy had a significantly shorter procedure time and a tendency toward less delayed bleeding compared to hot snare polypectomy.^[25] A total of 8 studies comprising 1665 patients and 3195 polyps were evaluated.

Combined laparoscopic/colonoscopic polypectomy or endolaparoscopic polypectomy (ELP) may be a safe and effective alternative to segmental resection, particularly for colonic polyps not amenable to exclusively colonoscopic removal because of their location, size, or tortuosity of the colon.^[26] In a retrospective study of 30 patients with benign colonic polyps, 22 (73%) underwent successful ELP surgery, 7 were converted to colonic mobilization and colotomy, and 1 was converted to laparoscopic colectomy.^[26]

Higher risk (eg, large, aggressive appearing) polyps are often marked at the time of resection by injection of ink (“tattooing”). This method helps to locate the site again, either during colonoscopy or surgery, for follow-up examination, biopsy, or resection.^[27] Resection of a large, flat or sessile lesion, particularly when it is removed in pieces, or a polyp with a focus of high-grade dysplasia or cancer is often followed by repeat endoscopy in 3 months to confirm complete excision.

Colonic resection

In the case of multiple intestinal polyps associated with FAP, colon resection remains the only feasible option. See the image below.

View Image

Familial adenomatous polyposis, total colectomy specimen. The colonic mucosa is studded with innumerable sessile and small pedunculated polyps, which ....

Colonic resection is also advocated for patients with long-standing ulcerative colitis who have developed high-grade dysplasia or a dysplasia-associated lesion or mass (DALM).^[6]

Surgical resection may be advocated for large, sessile polyps that are difficult to remove or for advanced colonic polyps that recur despite adequate initial endoscopic treatment.

Several surgical options should be discussed with the patient, including total colectomy, subtotal colectomy with rectal sparing, or segmental resection.

• References

Prevention

Currently, no definitive guidelines exist regarding the prevention of the development of colonic polyps. However, note the following:

• Calcium may be modestly protective.
• Fiber may also have some activity; the best evidence is for cereal fiber.
• Aspirin may be considered in select patients.
• Studies have demonstrated that a diet high in antioxidants has no impact on colonic polyp recurrence.
• In one study, supplementary folate was also found to have no benefit, although this conclusion bears the caveat that the tested population had substantial basal folate intake. Thus, some folate intake may be protective.

See the Guidelines section for colorectal cancer screening recommendations from the US Multi-Society Task Force (MSTF), which represents the American College of Gastroenterology (ACG), the American Gastroenterological Association (AGA), and the American Society for Gastrointestinal Endoscopy (ASGE).

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Long-Term Monitoring

Surveillance colonoscopy for early detection of colorectal cancer is probably unnecessary in those with low-risk adenomas (ie, 1-2 adenomas < 10 mm in size), whereas patients with 3 or more adenomas or adenomas larger than 10 mm should undergo surveillance colonoscopy at 3 years after baseline.^[28]

Most gastroenterologists advocate repeat colonoscopy 5 years following complete removal of a low-risk adenomatous polyp (as defined histologically). Colonoscopy is repeated in 3 years if the polyp has higher-risk features. Repeat colonoscopy may be advised in 3-12 months if the adequacy of polyp removal is a matter of substantial doubt. If no colonic polyps are found at the initial examination, follow-up colonoscopy at approximately 10-year intervals is recommended.

See the Guidelines section for colorectal cancer screening recommendations from the US Multi-Society Task Force (MSTF), which represents the American College of Gastroenterology (ACG), the American Gastroenterological Association (AGA), and the American Society for Gastrointestinal Endoscopy (ASGE).

• References

Guidelines Summary

The US Multi-Society Task Force on Colorectal Cancer (MSTF) represents the American College of Gastroenterology (ACG), the American Gastroenterological Association (AGA), and the American Society for Gastrointestinal Endoscopy (ASGE). Their screening and surveillance guidelines are summarized below.

2017 MSTF screening guidelines for colorectal cancer

The MSTF guidelines may be found here. Strong recommendations include the following^[9] :

• Clinicians should offer screening for colorectal cancer beginning at age 50 years for non-black average-risk individuals (beginning at age 45 years for black individuals).
• Colonoscopy is recommended every 10 years or an annual fecal immunochemical testing (FIT) for those at average risk for colorectal neoplasia.
• Physicians performing screening colonoscopy should measure quality, including the adenoma detection rate.
• Computed tomography (CT) colonography is recommended every 5 years or FIT-fecal DNA every 3 years or flexible sigmoidoscopy every 5-10 years in those who refuse colonoscopy and FIT.
• Clinicians should offer annual FIT to those with one or more first-degree relatives with colorectal cancer or documented advanced adenomas but who decline colonoscopy.
• It is recommended that adults younger than 50 years with colorectal bleeding symptoms undergo colonoscopy or an evaluation sufficient to identify the cause of bleeding, and that clinicians initiate treatment and thorough follow-up to determine resolution of the bleeding.

Individuals with high-risk family histories not associated with polyp syndromes

For those with a family or personal history of Lynch syndrome, colorectal cancer screening by colonoscopy is recommended every 1-2 years, beginning between ages 20 and 25 years or 2−5 years before the youngest age of diagnosis of colorectal cancer in the family if they were diagnosed before age 25 years.^[29]

In the presence of a family history of family colon cancer syndrome X, colonoscopy is recommended every 3-5 years, beginning 10 years before the age of diagnosis of the youngest affected relative.^[9]

For those with a family history of colorectal cancer or an advanced adenoma in two first-degree relatives diagnosed at any age OR colorectal cancer or an advanced adenoma in a single first-degree relative at age younger than 60 years, colonoscopy is recommended every 5 years beginning before the age at diagnosis of the youngest affected relative or age 40 years (whichever is earlier). Those with a single first-degree relative with colorectal cancer without significant neoplasia by age 60 years may consider in consultation with their physicians a longer interval between colonoscopies.^[9]

In the presence of colorectal cancer or an advanced adenoma in a single first-degree relative who was diagnosed at age 60 years or older, initiate screening at age 40 years and then follow the screening recommendations for tests and intervals for persons at average risk.^[9]

2016 MSTF guidelines on colonoscopy surveillance after colorectal cancer resection

These MSTF guidelines may be found here. Strong recommendations include the following^[30] :

• Patients with colorectal cancer should undergo high-quality perioperative clearing with colonoscopy, either preoperatively or, in the case of obstructive colorectal cancer, within a 3-6–month interval after surgery.
• Patients who have undergone curative resection of either colon or rectal cancer should receive their first surveillance colonoscopy 1 year postoperatively (or 1 year after the clearing perioperative colonoscopy). (Additional recommendations apply for those with rectal cancer, but they are classified as weak with low-quality evidence.)
• Following the 1-year colonoscopy, the next colonoscopies should be 3 years and then 5 years, and thereafter at 5-year intervals until the benefits of continued surveillance are outweighed by decreased life expectancy. In the presence of neoplastic polyps during any colonoscopy, polyp surveillance intervals should be based on published recommendations.
• CT colonography is the best alternative to exclude synchronous neoplasms in those with obstructive colorectal cancer precluding complete colonoscopy.

The MSTF indicates there is insufficient evidence to recommend routine use of FIT or fecal DNA surveillance following resection for colorectal cancer.^[30]

2012 MSTF guidelines for colonoscopy surveillance after screening and polypectomy

These MSTF guidelines may be found here. Recommendations with moderate to high quality of evidence include the following^[31] :

• In those with average risk for colorectal cancer and no adenomas or polyps on baseline examination, and for those with no adenomas but do have distal small (< 10 mm) hyperplastic polyps, the next evaluation is recommended in 10 years (moderate quality of evidence for both).
• In those with one to two small (< 10 mm) tubular adenomas on baseline evaluation, the next examination is recommended in 5-10 years (moderate quality of evidence).
• A 3-year interval is recommended for (1) those with 3-10 adenomas at baseline examination (moderate quality of evidence if any polyp ≥6 mm; low quality of evidence if all polyps < 6 mm), (2) individuals with one or more tubular adenomas of at least 10 mm in size at baseline evaluation (high quality of evidence), (3) individuals with one or more adenomas with villous features of any size (moderate quality of evidence), as well as (4) those with one or more adenomas with high-grade dysplasia (moderate quality of evidence).
• An interval shorter than 3 years is recommended for those with more than 10 adenomas at baseline examination (moderate-high quality of evidence).

Recommendations for polyp surveillance after first surveillance colonoscopy ^[31]

In the presence of low-risk or high-risk adenomas at baseline evaluation and then high-risk adenoma at first surveillance, the second surveillance should take place in 3 years. But if low-risk adenomas are present at first surveillance, the next surveillance is in 5 years.

For those with low-risk adenomas at baseline and no adenomas at first surveillance, second surveillance is 10 years. However, in the presence of high-risk adenomas at baseline colonoscopy and no adenomas at first surveillance, the next surveillance is in 5 years; if the results on second surveillance are negative, insufficient evidence exists for the MSTF to make a recommendation.

• References

Medication Summary

No drug therapy is proven or recommended for colonic polyps. More studies are required to assess the potential use of nonsteroidal anti-inflammatory drugs (NSAIDs) in order to elucidate their mechanism of action in causing colonic polyp regression and to determine why they do not appear to prevent cancer development.

• References