This document discusses screening and diagnosis of colorectal cancer. It covers risk factors like aging, hereditary factors, diet, and inflammatory bowel disease. Common presentations include changes in bowel habits, hematochezia, and obstructive symptoms. Screening tests aim to detect early-stage cancer and include colonoscopy every 10 years, annual fecal immunochemical testing, and computed tomography colonography every 5 years. For high-risk patients, more frequent screening is recommended. Diagnostic tests following positive screening include colonoscopy, stool DNA testing, and imaging. Genetic testing guides screening for familial cancer syndromes.
3. Introduction
ï” Incidence colorectal carcinoma is the most common malignancy of the
gastrointestinal tract
ï” Incidence is similar in men and women and has
remained fairly constant over the past 20 years; however, the
widespread adoption of current national screening programs is gradually
decreasing the incidence in people over 50 years
ï” Early detection thought to be responsible for the decreasing mortality
3
4. Risk Factors
ï” Aging
Dominant risk factor
Incidence rising steadily after age 50 years. More than 90% of cases diagnosed are
in people older than age 50 years.
ï” Hereditary Risk Factors
80% of colorectal cancers occur sporadically, while 20% arise in patients with a
known family history
4
5. Risk Factors
ï” Environmental and Dietary Factors.
Observation that colorectal carcinoma occurs more commonly in:
- Populations that consume diets high in animal fat and
low in fiber has led to the hypothesis that dietary factors contribute to
carcinogenesis
- Obesity and sedentary lifestyle
5
6. Risk Factors
ï” Inflammatory Bowel Disease
Long-standing colitis from inflammatory bowel disease are at increased risk
for the development of colorectal cancer.
6
7. Risk Factors
ï” Other risk factors
Cigarette smoking is associated with an increased risk of colonic adenomas
Primary sclerosing cholangitis
Acromegaly
Low socioeconomic status
7
8. Clinical Presentation
ï” Patients with colorectal cancer (CRC) may present in three ways:
1) Suspicious symptoms and/or signs , EXAMPLES?
2) Asymptomatic individuals
3) Emergency admission , EXAMPLES?
8
10. Clinical Presentation
â Change in bowel habits is a more common presenting symptom for left-sided
than right-sided CRCs. How?
â Hematochezia
â Iron deficiency anemia
10
13. Clinical Presentation
ï” CRC can spread by lymphatic and hematogenous dissemination, as well as by
contiguous and trans peritoneal routes.
ï” The most common metastatic sites are the regional lymph nodes, liver, lungs,
and peritoneum.
ï” Patients may present with signs or symptoms referable to any of these areas.
13
14. Clinical Presentation
ï” Unusual presentations
â CRC may be detected on the basis of discovery of liver
metastases that are detected incidentally during studies
â Fever of unknown origin
14
15. Screening and Surveillance
ï” The diagnosis of a colorectal cancer (CRC) is made by histologic examination
of a biopsy that is usually obtained during lower gastrointestinal tract
endoscopy or from a surgical specimen.
ï” Screening is intended for patients without signs or symptoms
of possible CRC. At present, most guidelines suggest initiating
screening at the age of 50.
ï” Once a CRC is suspected, the next test can be a colonoscopy
15
16. Screening and Surveillance
ï” Screening tests for CRC can improve disease prognosis by:
- Identifying early-stage CRC that is easier to treat and has a lower mortality
rate than CRC detected after symptoms develop.
- In addition, screening can prevent CRC by detecting and removing
premalignant polyps before they progress to CRC
16
17. Screening and Surveillance
ï” Initial risk assessment to determine if a patient is at increased risk for CRC
at a first office visit and update the information at a minimum of every five
years.
ï” Harms associated with screening â Most of the harms of screening for CRC
are related to the risks from colonoscopy, including perforation
17
18. Screening and Surveillance
ï” CHOOSING A SCREENING TEST
The best screening test is one that the patient is willing to complete according
to the test instructions
Noninvasive screening tests such as FIT and multitarget stool DNA testing (MT-
sDNA) can be mailed directly to patients to be completed in the comfort of their
homes. This approach makes it possible to provide screening directly to patients
as a primary approach or when a face-to-face visit is not possible or safe to do.
18
19. Screening and Surveillance
ï” Multiple screening tests are available to detect colorectal cancer (CRC)
before they become symptomatic. Differ with regard to:
Sensitivity and specificity
Frequency of testing
Evidence of effectiveness
Convenience
Safety
Availability
Cost.
19
20. Diagnostic Tests
Laboratory tests
ï” Tumor markers â A variety of serum markers have been associated with CRC,
particularly carcinoembryonic antigen (CEA). (Low diagnostic ability)
ï” Although CRC is often associated with iron deficiency anemia
ï” There is no diagnostic role for other routine laboratory test, including liver
function tests
20
21. Diagnostic Tests
Stool DNA
ï” Neoplastic lesions of the colon shed cells into the lumen posing an
opportunity for detection via DNA testing
ï” This test, in combination with FIT is supported as a screening modality every
1 to 3 years
21
22. Diagnostic Tests
Colonoscopy
ï” We advise colonoscopy every 10 years for most patients at average risk for
CRC who are willing to undergo this procedure.
ï” Screening with colonoscopy is associated with reduced incidence and
mortality from CRC.
ï” Among screening tests, colonoscopy has the highest sensitivity for CRC and
allows lesion removal anywhere in the colon during just one procedure
22
23. Diagnostic Tests
Colonoscopy
ï” When an adequate screening colonoscopy is accomplished, intercurrent stool
tests are not necessary.
ï” In addition, for patients who have had a negative colonoscopy and have
been recommended to have routine screening in 10 years, screening with FIT
or other screening tests is not indicated
What else
after
colonoscopy?
23
24. Screening and Surveillance
When screening stool tests are positive, and colonoscopy is then completed (to
the cecum with adequate bowel preparation) and without abnormality,
patients should return
to the routine
screening schedule.
24
25. Diagnostic Tests
Colonoscopy
ï” Colonoscopy is the most accurate and versatile diagnostic test for CRC.
Biopsy
polypectomy
For endoscopically visible lesions, methods for tissue sampling
25
26. Diagnostic Tests
Colonoscopy
ï” Advantages
Colonoscopy is the definitive test for detection of precancerous adenomas and
CRC with high sensitivity and acceptable specificity.
ï” Disadvantages
Sedation is used, a recovery period is needed
Inconvenience of bowel preparation.
Possibility of perforation, major bleeding, and infection
26
27. Diagnostic Tests
Fecal immunochemical testing
ï” Directly measures hemoglobin in the stool
ï” We advise screening by FIT for occult blood annually on a single sample,
when?
- Unwilling or unable to have a colonoscopy as initial screening
- Access to colonoscopy is limited
FIT is more sensitive and specific for cancer than FOBT
27
28. Diagnostic Tests
Fecal immunochemical testing
ï” Advantages
Dietary and medication restrictions are not needed
Does not require a bowel preparation, sedation, or time away from work or
family
FIT requires only one sample rather than three days of samples as for guaiac-
based fecal occult blood testing (gFOBT)
ï” Disadvantages
if the FIT is positive, a colonoscopy will be advised for further evaluation).
28
29. Diagnostic Tests
Guaiac-based fecal occult blood test (gFOBT)
ï” Guaiac testing identifies hemoglobin by turning guaiac reagent-impregnated
paper blue as the result of a peroxidase reaction
ï” FOBT is relatively insensitive
ï” gFOBT is usually performed annually.
29
30. Diagnostic Tests
Guaiac-based fecal occult blood test (gFOBT)
ï” Advantages
Noninvasive
Does not require bowel preparation or sedation
ï” Disadvantages
Sample collection takes a longer time than for FIT
Three consecutive samples are required.
What about upper
endoscopy?
Positive results may also
occur with upper
gastrointestinal bleeding.
30
31. Diagnostic Tests
Sigmoidoscopy
ï” Sigmoidoscopy can only identify lesions up to the distal 60 cm of the bowel.
This may be problematic in women and older patients because they have a
higher frequency of more proximal lesions.
ï” Sigmoidoscopy every five years is a screening option recommended
ï” Small polyps can be biopsied/removed during sigmoidoscopy. However,
excision of larger lesions (>1.0 cm) is usually done during a subsequent
colonoscopy.
31
32. Diagnostic Tests
Sigmoidoscopy
ï” Generally, not considered to be an adequate diagnostic study for a patient
suspected of having a CRC, unless a palpable mass is felt in the rectum. In such
cases, a full colonoscopy will still be needed to evaluate the remainder of the
colon for synchronous polyps and cancers
ï” Advantages
Minimal patient preparation and does not require sedation.
ï” Disadvantages
Sigmoidoscopy examines only the distal portion of the colon.
Colon perforation is the most important complication of sigmoidoscopy.
32
33. Diagnostic Tests
Computed tomography colonography
ï” Obtaining multiple, thin-slice CT data and using computers to construct
images of the bowel mucosa in two and three dimensions, with other
enhancements to assist in interpretation.
ï” CTC is usually performed every five years
ï” More sensitive than any test other than colonoscopy
ï” Limitations: 1) False positive
results
2) Lacks
capability for
biopsy or
removal of
polyps
33
34. Diagnostic Tests
Computed tomography colonography
ï” Colonoscopy is required promptly for evaluation in case of polyps of CRC
ï” For older patients with comorbidities (eg, cardiopulmonary disease, diabetes mellitus, or history
of stroke), CTC might be preferred over colonoscopy.
ï” CT colonography has been evaluated in patients with incomplete colonoscopy
34
35. Diagnostic Tests
Computed tomography colonography
ï” Reasons for incompleteness include the inability of the colonoscope to reach
the tumor or to visualize the mucosa proximal to the tumor for:
- Technical reasons
- Patient intolerance of the examination.
35
36. Diagnostic Tests
Capsule colonoscopy
ï” In this test, the patient swallows a capsule containing tiny video cameras. A
stool preparation is needed; however, sedation is not needed
ï” Capsule colonoscopy every five years
ï” Although it is not among the tests included in several screening guidelines
36
37. Other Tests Used
Sigmoidoscopy combined with FIT (or sensitive gFOBT)
ï” The combination of sigmoidoscopy with FIT or guaiac-based FOBT (gFOBT) theoretically
enhances lesion detection by offering direct visualization up to 60 cm as well as by detecting
colon lesions beyond the reach of a sigmoidoscope by testing for occult blood.
ï” The recommended frequencies of each test vary among expert guidelines. USPSTF recommends
sigmoidoscopy every 10 years with annual FIT, which is also an option in ASCO guidelines [10,38].
NCCN includes an option for sigmoidoscopy every five years with annual FOBT [36]. ACP includes
sigmoidoscopy every five years plus combined FOBT or FIT every three years
37
38. Air contrast barium enema
ï” Air-Contrast Barium Enema.
ï” Air-contrast barium enema is also highly sensitive for detecting polyps greater
than 1 cm in diameter (90% sensitivity). Unfortunately, there are no studies proving
its efficacy for screening large populations. Accuracy is greatest in the proximal
colon but may be compromised in the sigmoid colon if there is significant
diverticulosis. The major disadvantages of barium enema are the need for
mechanical bowel preparation and the requirement for colonoscopy if a lesion is
discovered.
38
39. Screening for colorectal cancer in patients
with a family history of colorectal cancer
ï” Age to begin screening â We initiate screening at age 40 years or 10 years
before youngest
ï” Colonoscopy every five to ten years.
ï” If the patient declines colonoscopy, and FIT is used for screening, it is
performed annually
ï” Individuals at highest risk due to high-risk familial CRC syndromes should be
screened for CRC with colonoscopy at frequent specified intervals.
39
40. Familial Adenomatous Polyposis (FAP)
ï” The lifetime risk of colorectal cancer in FAP patients approaches 100% by age
50 years
ï” APC gene testing may be used to screen family members, providing an
APC mutation has been identified.
annual flexible sigmoidoscoy
beginning at age 10 to 15
years until polyps are
identified
APC
testing
can be
screened starting
at age 50 years
40
41. Familial Adenomatous Polyposis (FAP)
APC
testing
Annually
Until 24
Every 2
years
until 34
Every 3
years
until 44
Every 3 to
5 years
Flexible sigmoidoscopy
beginning at age 10 to 15
Refused
Unavailable
Mutation cannot
be identified
41
42. Familial Adenomatous Polyposis (FAP)
ï” FAP patients are also at risk for the development of adenomas anywhere in
the gastrointestinal tract, particularly in the duodenum. Periampullary
carcinoma is a particular concern. Upper endoscopy is therefore
recommended for surveillance every 1 to 3 years beginning at age 25 to 30
years.
ï” Once the diagnosis of FAP has been made and polyps are developing,
treatment is surgical.
42
43. Lynch Syndrome
Amesterdam criteria
ï” The Amsterdam I criteria for clinical diagnosis of Lynch syndrome are
Three affected relatives
Two successive generations of a family
One patient diagnosed before age 50 years
43
44. Lynch Syndrome
ï” Amesterdam criteria
The presence of other related carcinomas should raise the suspicion of this
syndrome. Revised criteria Amsterdam II requires three or more relatives with an
HNPCC related malignancy in which at least one is a first degree relative
of the others, two generations are affected, at least one cancer occurred
before age 50, FAP has been excluded, and pathology of the tumors has been
reviewed and confirmed
44
45. Lynch Syndrome
ï” Because of the high risk of endometrial carcinoma, transvaginal ultrasound or
endometrial aspiration biopsy is also recommended annually after age 25 to 35
years.
ï” Similarly, prophylactic hysterectomy and bilateral salpingo-oophorectomy should
be considered in women who have completed childbearing.93-9
10 years
younger than the
youngest age
Or
1?
at age 20 to 25
years
1?
Flexible sigmoidoscopy
Annually
45
49. SUMMARY
ï” We advise colonoscopy every 10 years for most patients at average risk for
CRC who are willing to undergo this procedure. We advise screening by FIT for
occult blood annually on a single sample, by multitarget stool DNA (MT-sDNA)
testing every three years, or by computed tomography colonography (CTC)
every five years for patients unable or unwilling to have a colonoscopy as
initial screening, or when access to colonoscopy is limited, with the
understanding that if the other test results are positive, colonoscopy needs to
be performed promptly. (See 'Preferred tests' above.)
ï” âąOther tests available for CRC screening include sigmoidoscopy with FIT or
with gFOBT, sigmoidoscopy alone, gFOBT alone, and capsule colonoscopy
49
Third most commonly diagnosed cancer in males and the second in females
However, individuals of any age can develop colorectal cancer, so symptoms such as a significant change in bowel habits, rectal bleeding, melena, unexplained anemia or weight loss require through evaluation
 Animal studies suggest that fats may be directly toxic to the colonic mucosa and thus may induce early malignant change
Obesity and sedentary lifestyle dramatically increase cancer-related mortality in a number of malignancies, including colorectal carcinoma
chronic inflammation predisposes the mucosa to malignant changes,
1) Suspicious symptoms and/or signs , EXAMPLES? unexplained iron deficiency anemia, weight loss , change in bowel habits , Symptoms from the local tumor â Typical 2) Asymptomatic individuals discovered by routine screening
3) Emergency admission with intestinal obstruction, peritonitis, or rarely, an acute gastrointestinal bleed, hematochezia , melena, Less common presenting symptoms include abdominal distention, and/or nausea and vomiting, which may be indicators of obstruction
Additionally, if the patient has gastrointestinal symptoms or signs (eg, iron deficiency anemia, upper gastrointestinal symptoms), a diagnostic evaluation is indicated.Â
âA change in bowel habits is a more common presenting symptom for left-sided than right-sided CRCs.
Fecal contents are liquid in the proximal colon and the lumen caliber is larger, and CRCs are therefore less likely to be associated with obstructive symptoms, including colicky pain.
EXAMPLES OF RIGHT SIDED TUMORS WITH OBSTRUCTIONS SYMPTOMS >>> ILEOCECAL VALVE CANCER
âHematochezia is more often caused by rectosigmoid than right-sided colon cancer.
âIron deficiency anemia from unrecognized blood loss is more common with right-sided CRCs
Obstructive symptoms are more common with cancers that encircle the bowel, producing the so-called "apple-core" description as seen most classically on barium enema
Patients may present with signs or symptoms referable to any of these areas. The presence of right upper quadrant pain, abdominal distention, early satiety, supraclavicular adenopathy, or periumbilical nodules usually signals advanced, often metastatic disease
âCRC may be detected on the basis of discovery of liver metastases that are detected incidentally during studies such as gallbladder or renal ultrasound, or CT scans for evaluation of other symptoms (eg, dyspnea).
âFever of unknown origin
intraabdominal, retroperitoneal, abdominal wall or intrahepatic abscesses due to a localized perforated colon cancer
Recommended proce-dures include yearly FOBT/FIT, flexible sigmoidoscopy every 5 years, FOBT/FIT and flexible sigmoidoscopy in combination, air-contrast barium enema every 5 years, or colonoscopy every 10 years. Patients with other risk factors should be screened earlier and more frequently
We do an initial risk assessment to determine if a patient is at increased risk for CRC at a first office visit and update the information at a minimum of every five years. Patients at sufficiently increased risk to change screening recommendations (eg, start screening at an earlier age and/or perform screening more frequently) include those with a personal or family history of CRC or advanced adenomatous polyp and other risk factors
Harms associated with screening â Most of the harms of screening for CRC are related to the risks from colonoscopy, including perforation Any abnormal results of initial screening tests other than colonoscopy (eg, stool test, virtual colonoscopy) necessitate a colonoscopy to evaluate the abnormality; thus, all screening modalities are associated with the potential for colonoscopy-associated complications
Noninvasive screening tests such as FIT and multitarget stool DNA testing (MT-sDNA) can be mailed directly to patients to be completed in the comfort of their homes. This approach makes it possible to provide screening directly to patients as a primary approach or when a face-to-face visit is not possible or safe to do. such as during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic
Although CRC is often associated with iron deficiency anemia, its absence does not reliably exclude the disease.
There is no diagnostic role for other routine laboratory test, including liver function tests, which lack sensitivity for detection of liver metastases
Tumor markers â A variety of serum markers have been associated with CRC, particularly carcinoembryonic antigen (CEA). However, all these markers, including CEA, have a low diagnostic abilityÂ
Among screening tests, colonoscopy has the highest sensitivity for CRC and and allows lesion removal anywhere in the colon during just one procedure with the potential to detect as well as prevent cancer by removing adenomatous polyps prior to malignant transformation
Colonoscopy.
Colonoscopy is currently the most accurate and most complete method for examining the large bowel. This procedure is highly sensitive for detecting even small polyps (<1 cm) and allows biopsy, polypectomy, control of hemor-rhage, and dilation of strictures. However, colonoscopy does require mechanical bowel preparation, and the discomfort asso-ciated with the procedure requires conscious sedation in most patients. Colonoscopy is also considerably more expensive than other screening modalities and requires a well-trained endos-copist. The risk of a major complication after colonoscopy (perforation and hemorrhage) is extremely low (0.2â0.3%). Nevertheless, deaths have been reported.
When a screening FIT, gFOBT, or MT-sDNA stool tests are positive, and colonoscopy is then completed (to the cecum with adequate bowel preparation) and without abnormality, patients should return to the routine screening schedule.
Colonoscopy is the most accurate and versatile diagnostic test for CRC, since it can localize and biopsy lesions throughout the large bowel
Sedation is used, a recovery period is needed and there is a potential for sedation-related complications.
Disadvantages of colonoscopy as a screening test include the inconvenience of bowel preparation.Â
The risk of perforation is increased by comorbidities, increasing age, polypectomy, and less-experienced endoscopists [57,58]. Among frail patients, there is a potential for dehydration or electrolyte disturbances resulting from the bowel preparation.
, with the understanding that if the FIT result is positive, colonoscopy needs to be performed promptly.
FOBT is relatively insensitive, why is that ? Guaiac testing of stool samples can identify hemoglobin that may be present due to bleeding from a colon lesion or for other reasons.
However, the test is to be done annually, and sample collection takes a longer time than for FIT because three consecutive samples are required
If the gFOBT is positive, a colonoscopy will be advised for further evaluation.
If the option of adding a stool-based test is not available or practical for a patient to do in conjunction with sigmoidoscopy, then screening with sigmoidoscopy every 5 to 10 years may be offered alone.
Flexible Sigmoidoscopy.Â
Screening by flexible sigmoidoscopy every 5 years may lead to a 60% to 70% reduction in mortality from colorectal cancer, chiefly by identifying high-risk individuals with adenomas. However, it is important to recognize that lesions in the proximal colon cannot be identified, and for this reason, flexible sigmoidoscopy has often been paired with air-contrast barium enema to detect transverse and right colon lesions. Patients found to have a polyp, cancer, or other lesion on flexible sigmoidoscopy will require colonoscopy.
Advances in imaging technology have created a num-ber of less invasive, but highly accurate tools for screening. CT colonography makes use of helical CT technology and three-dimensional reconstruction to image the intraluminal colon. At present, patients require a mechanical bowel preparation. The colon is then insufflated with air, a spiral CT is performed, and both two-dimensional and three-dimensional images are gener-ated. In the hands of a qualified radiologist, sensitivity appears to be as good as colonoscopy for colorectal cancers and polyps greater than 1 cm in size.103 Colonoscopy is required if a lesion is identified. CT colonography has also been used for imag-ing the proximal colon in cases of obstruction or if a colonos-copy cannot be completed in selected patients. Limitations of this technique include false-positive results from retained stool, diverticular disease, haustral folds, motion artifacts, and an inability to detect flat adenomas.
Although it can overcall stool as masses in poorly distended or poorly prepared colons; it also lacks the capability for biopsy or removal of polyps
For older patients with comorbidities (eg, cardiopulmonary disease, diabetes mellitus, or history of stroke), CTC might be preferred over colonoscopy. because the risks of colonoscopy increase with age [45]. However, patients with abnormal findings on CTC should undergo colonoscopy.
Reasons for incompleteness include the inability of the colonoscope to reach the tumor or to visualize the mucosa proximal to the tumor for technical reasons (eg, partially or completely obstructing cancer, tortuous colon, poor preparation)
and patient intolerance of the examination.
available data suggest that CT colonography provides a similarly sensitive, less invasive alternative to colonoscopy in patients presenting with symptoms suggestive of CRC. However, given that colonoscopy permits removal/biopsy of the lesion and any synchronous cancers or polyps that are seen during the same procedure, in our view, colonoscopy remains the gold standard for investigation of symptoms suggestive of CRC.
Colon capsule endoscopy requires a bowel preparation; however, it does not require sedation or dietary or medication adjustments. Colon capsule endoscopy does not allow for biopsy or polyp removal during the test because lesion detection is done by visualization with a camera that is not attached to any other instruments
The combination of sigmoidoscopy with FIT or guaiac-based FOBT (gFOBT) theoretically enhances lesion detection by offering direct visualization up to 60 cm as well as by detecting colon lesions beyond the reach of a sigmoidoscope by testing for occult blood. FIT is preferred over sensitive gFOBT.
Fecal Occult Blood Testing and Flexible Sigmoidoscopy.
Several trials have shown that FOBT screening is least effective at detecting rectosigmoid cancers.97-99 This is precisely the area screened by flexible sigmoidoscopy; thus, the combination of the two tests has been suggested as a reasonable screening strategy.
American Cancer Society recommendations that one of the acceptable screening regimens for average-risk Americans is the combination of FOBT/FIT annually and flexible sigmoidoscopy every 5 years; this combination was preferred over either test alone. Recent NCCN guidelines offer the option of flexible sigmoidoscopy with stool-based testing every 10 years. The addition of air-contrast barium enema to assess the proximal colon may improve sensitivity as well.96
Patients who refuse to undergo colonoscopy should be encouraged to undergo CRC screening with another screening test. For such patients, FIT may be an attractive alternative because it is noninvasive [24,39,40]. However, maintaining the screening schedule can be a challenge because FIT should be repeated annually. A positive FIT requires timely follow-up with colonoscopy.
If APC testing is positive in a relative of a patient with a known APC mutation
If APC testing is negative, the relative can be screened starting at age 50 years per average risk guidelines.
If APC testing is refused or unavailable, or if a mutation cannot be identified, annual flexible sigmoidoscopy beginning at age 10 to 15 years is performed until age 24 years. Screening flexible sigmoidoscopy is then done every 2 years until age 34 years, every 3 years until age 44 years, and then every 3 to 5 years.
may also be associated with extracolonic malignancies, including endometrial carcinoma, which is most common in women, and ovarian, pancreas, stomach, small bowel, biliary, and urinary tract carcinomas. The diagnosis is made based on family history. The Amsterdam I criteria for clinical diagnosis of Lynch syndrome are three affected relatives
may also be associated with extracolonic malignancies, including endometrial carcinoma, which is most common in women, and ovarian, pancreas, stomach, small bowel, biliary, and urinary tract carcinomas. The diagnosis is made based on family history. The Amsterdam I criteria for clinical diagnosis of Lynch syndrome are three affected relatives
Screening colonoscopy is recommended annually for atrisk patients beginning at either age 20 to 25 years or 10 years younger than the youngest age at diagnosis in the family, whichever comes first
may also be associated with extracolonic malignancies, including endometrial carcinoma, which is most common in women, and ovarian, pancreas, stomach, small bowel, biliary, and urinary tract carcinomas. The diagnosis is made based on family history. The Amsterdam I criteria for clinical diagnosis of Lynch syndrome are three affected relatives
