Colorectal Cancer

Colorectal cancer (CRC) is the third most common form of cancer in the U.S. While sporadic colon cancers are more common, hereditary colon cancers are also frequent, and identification of these affects screening recommendations both for the individual and family members. CRC screening strategies rely on imaging, laboratory testing, or a combination of the two. No serum biomarkers have been validated for CRC diagnosis; however, monitoring of serum carcinoembryonic antigen (CEA) is recommended following resection of most CRCs to detect recurrence. Molecular testing of cancer tissue, including evaluation for microsatellite instability (MSI), is recommended to guide treatment decisions, especially in individuals at high risk for hereditary nonpolyposis colorectal cancer (HNPCC).

Tabs Content

Clinical Overview

Diagnosis

Indications for Testing

Rectal bleeding, melena, hematochezia
Change in bowel habits (eg, constipation, narrow stools, excessive flatulence)
Abdominal pain or discomfort; may be accompanied by weight loss, fatigue, and/or anemia
Family history of CRC
Clinical symptoms consistent with genetic/hereditary CRC (eg, Lynch syndrome [HNPCC], MUTYH-associated polyposis [MAP], familial adenomatous polyposis [FAP], Turcot syndrome, Gardner syndrome)

Laboratory Testing

Initial testing (National Comprehensive Cancer Network [NCCN], Colon Cancer, 2018)
- CBC, chemistry profile – to determine baseline health status
- CEA – not useful for screening, diagnosis, or prognosis; use to monitor for recurrence

Molecular testing

Tissue from metastatic or recurrent colorectal tumor – preferred if present; otherwise, primary tissue is acceptable
Formalin-fixed, paraffin-embedded tissue – preferred for biomarker testing; other specimen testing has not been validated

Molecular biomarkers and recommendations for testing (American Society for Clinical Pathology (ASCP), College of American Pathologists (CAP), Association for Molecular Pathology (AMP), and American Society of Clinical Oncology (ASCO), 2017)

Molecular Biomarkers and Recommendations for Testing Based on Guideline from ASCP, CAP, AMP, and ASCO (2017)
Marker(s)	Appropriate Population to Test	Recommended Use
RAS (“expanded” or “extended” RAS) KRAS NRAS Codons 12, 13 of exon 2 Codons 59, 61 of exon 3 Codons 117, 146 of exon 4	Patients with CRC being considered for anti-EGFR therapy	Determine eligibility for anti-EGFR monoclonal antibody therapy in patients with metastatic CRC – mutations in RAS are associated with lack of response to anti-EGFR therapy
BRAF p.V600	Select patients with CRC, including those with metastatic disease	Prognostic stratification Patients with BRAF-mutated CRC have a worse outcome relative to patients with nonmutated tumors Insufficient evidence to recommend BRAF mutational status as a predictive molecular biomarker for response to anti-EGFR therapy
BRAF pV600E	Patients with MMR-deficient CRC tumors with loss of MLH1	Evaluate for Lynch syndrome risk Presence of BRAF mutation strongly favors sporadic pathogenesis Absence of BRAF mutation does not exclude Lynch syndrome
MMR status	All patients with CRC	Prognostic stratification Evaluate for Lynch syndrome risk Presence of MMR protein deficiency warrants further workup Identify patients at high risk for Lynch syndrome
PIK3CA	n/a	Insufficient evidence to recommend testing for therapy selection outside of clinical trials
PTEN (IHC or FISH)	n/a
EGFR, epidermal growth factor receptor; FISH, fluorescence in situ hybridization; IHC, immunohistochemistry; MMR, mismatch repair; n/a, not applicable Source: Sepulveda, ASCP, CAP, AMP, and ASCO, 2017

Genetic testing for other CRC syndromes should be based on clinical presentation and family history and in conjunction with genetic consultation
- Refer to NCCN guideline – Genetic/Familial High Risk Assessment: Colorectal, 2017

Histopathology

All polyps removed should be histologically examined
All tumors should be tested by immunohistochemistry (IHC) for mismatch repair (MMR) deficiency (or polymerase chain reaction [PCR] for MSI)

Prognosis

Prognosis for CRC is dependent on clinical and tumor factors
- Patient age
- Cancer stage
- Histology
- Depth of penetration of primary tumor
- Number of lymph nodes evaluated and number positive
- Lymphocytic invasion
- Perineural invasion
- Anatomic location – patients with left-side tumors have better prognosis than those with right-side tumors
Markers for prognosis include
- MSI/MMR-deficient tumors – generally more favorable prognosis
- Chromosomal alterations in 8p, 17p, 18p – associated with poor prognosis
- Serum markers
  - CEA – measure prior to surgery (NCCN, Colon Cancer, 2018)
  - Carbohydrate antigen (CA) 19-9 – potential but not validated serum marker
    - Elevation at baseline may predict worse prognosis
  - Circulating tumor cells (CTCs) – independent predictor of progression-free and overall survival

Differential Diagnosis

Diverticulitis
Inflammatory bowel disease
- Crohn disease
- Ulcerative colitis
Irritable bowel syndrome
Hemorrhoids/fissures

Screening

Colorectal Screening for Persons with Average Risk^a
Organization	Recommendation
USPSTF, 2016 AAFP, 2017	50-75 yrs – CRC screening recommended; no specific screening test is recommended (screening tests vary according to risks and benefits) 76-85 yrs – consider screening for individuals healthy enough for colonoscopy, who lack comorbidity that would limit life expectancy; adults in this age group who have never been screened for CRC are more likely to benefit >85 yrs – CRC screening not recommended
AAFP, 2010	50-75 yrs – 1 of the following screening regimens^b Annual screen for CRC using FOBT Sigmoidoscopy every 5 yrs combined with high-sensitivity FOBT every 3 yrs Colonoscopy every 10 yrs 76-85 yrs – recommend against routine screening for CRC; however, there may be considerations that support CRC screening in an individual patient >85 yrs – CRC screening not recommended
ACS, 2018	45-75 yrs – 1 of the following regimens^b Flexible sigmoidoscopy every 5 yrs Colonoscopy every 10 yrs Double-contrast barium enema every 5 yrs CT colonography every 5 yrs ≥75 yrs – risks and benefits of screening should be discussed with patient by provider
^aAverage risk as defined by ACS – no history of adenoma or IBD; negative family history (having neither 1 first-degree nor 2 second-degree relatives with CRC, nor a clustering of Lynch syndrome-related cancers in the family, and no history of abdominal or pelvic radiation) ^bPatients with a family member diagnosed with colon cancer before 60 yrs should begin colonoscopy screenings every 5-10 yrs starting at age 40, or 10 yrs before the age of diagnosis of youngest family member diagnosed AAFP, American Academy of Family Practice; ACS, American Cancer Society; CT, computed tomography; FOBT, fecal occult blood test; IBD, inflammatory bowel disease; USPSTF, U.S. Preventive Services Task Force

High-risk patients
- Risk factors – personal or family history of CRC, adenomatous polyp, IBD, or other inheritable CRC syndrome; history of abdominal or pelvic radiation
- Begin screening earlier than in average-risk patients; may need to individualize screening based on risk factor

Screening Methodologies
Stool-Based Tests^a
Tests	Frequency	Description
FIT	Yearly	More accurate than gFOBT Can be performed with single specimen
FOBT (eg, gFOBT)	Yearly	50% of confirmed CRCs have a negative FOBT In at-risk patient, consider sigmoidoscopy or colonoscopy (even in presence of negative FOBT) Positive FOBT requires further evaluation (eg, colonoscopy)
FIT-DNA	Every 1-3 yrs	Multitargeted stool-based DNA testing Reasonable alternative to other stool-based and visualization-based tests (USPSTF, 2016) Emerging screening strategy that combines FIT with testing for altered DNA biomarkers in cells shed into stool Testing has increased single-test sensitivity for detecting CRC compared with FIT alone
Direct Visualization
Test		Frequency
Colonoscopy		Every 10 yrs
CT colonography		Every 5 yrs
Flexible sigmoidoscopy		Every 5 yrs
Combination Strategy
Test		Frequency
Flexible sigmoidoscopy with FIT		Sigmoidoscopy – every 10 yrs FIT – yearly
Serology Testing
Test		Description
Septin 9 DNA		Biomarker for presence of CRC – high negative predictive values Indicated for individuals ≥50 yrs with average risk and no family history of CRC or personal history of polyp removal or CRC Shown to detect cancers in cecum, ascending colon, transverse colon, splenic flexure, descending colon, sigmoid, rectosigmoid junction, and rectum
^aPositive tests require follow-up with direct visualization CT, computed tomography; FIT, fecal immunochemical test; FOBT, fecal occult blood test; gFOBT, guaiac fecal occult blood test; USPSTF, U.S. Preventive Services Task Force

Monitoring

Following definitive treatment, use a combination of laboratory testing and imaging to monitor patient
Laboratory testing
- Serum CEA
  - Elevated postoperative titer predicts tumor recurrence
  - Monitor for changes in concentration from preoperative baseline
    - Stage II or III tumors – measure every 3-6 months for 2 years after surgery, then every 6 months for a total of 5 years (NCCN, Colon Cancer, 2018)
  - Patient with metastatic disease – monitoring may help evaluate treatment response
- Emerging or investigational markers
  - Serum CTC – in metastatic tumors, used to monitor disease progression and response to therapy
  - Serum CA 19-9 – nonspecific marker; may provide additional information in conjunction with CEA

Pharmacogenetics

UGT1A1 genotyping
- The uridine diphosphate glucuronylsyltransferase 1A1 (UGT1A1) enzyme is responsible for clearance of irinotecan, a camptothecin analogue used in treatment of advanced colon cancer
- Decreased UGT1A1 gene expression may lead to drug toxicity (development of severe neutropenia)
  - Two gene variants responsible for 98-99% of genotypes in the Caucasian population – *1 and *28 (repeat TA sequence)
- NCCN recommendations regarding UGT1A1 and irinotecan treatment (NCCN, Colon Cancer, 2018)
  - Clinical guidelines for the role of UGT1A1 testing have not been established
  - Patients with Gilbert syndrome or elevated serum bilirubin may have UGT1A1 polymorphisms and should be treated with a decreased irinotecan dose and with caution
  - Pretreatment testing for UGT1A1 should be considered, and patients homozygous for the *28 allele should be treated with a decreased irinotecan dose and with caution
- CDC Evaluation of Genomic Applications in Practice Working Group recommendations (2011)
  - Consider selective genotyping based on patient preferences and predicted dosing
    - Higher doses are associated with increased risk for certain genotypes that may not occur with lower dosing
    - Patients homozygous for *1 may tolerate aggressive treatment better than patients with the *28 variant
5-fluorouracil (5-FU) sensitivity – genotyping of DYPD and TYMS
- Pharmacogenetic variations in genes such as DPYD and TYMS may help to predict toxicity and responsiveness of tumor to 5-FU therapy
  - Most DPYD or TYMS variants are associated with increased risk for 5-FU toxicity; alternative chemotherapeutic agents, therapeutic drug monitoring, altered 5-FU doses, or increased surveillance for adverse drug reactions may be indicated

Nomenclature, Allele Frequency, and Predicted Consequences
DPYD Gene Variants
DPYD Variant (Alternative Name[s])		Allele Frequency in Indicted Population	Predicted Consequences in Patients Receiving 5-FU
c.1679 T>G (DPYD13*, rs55886062)		0.1% – French Caucasians	Decreased DPD activity Increased toxicity risk
c.1905+1 G>A (DPYD2A*, IVS14+1 G>A, rs3918290)		0.47-2.2% – Dutch, German, French, Turkish, Finnish Absent – Japanese, Korean, African American	Abolished DPD activity Greatly increased toxicity risk
c.2846 A>T (rs67376798)		1.0% – French Caucasians	Decreased DPD activity Increased toxicity risk
TYMS Gene Variants
TYMS Variant (Alternative Name[s])		Allele Frequency in Indicated Population	Predicted Consequences in Patients Receiving 5-FU
3'-UTR 6 bp deletion (TTAAAG) (rs34489327; historically, rs163430)	Deletion	29.5% – Caucasian	Decreased TYMS expression Increased 5-FU responsiveness Increased risk of toxicity
	Insertion (wild type)	70.5% – Caucasian	Increased TYMS expression Decreased 5-FU responsiveness Decreased risk of toxicity
5'-TSER 28bp VNTR (2R; 3R) (rs34743033) G>C SNP in second repeat of 3R allele (3RC) (rs2853542)	2R	41-48% – Caucasian, Hispanic, African American 19% – Chinese 17.5% – Japanese	2R/3RG Increased TYMS expression Decreased 5-FU responsiveness Poor prognosis 2R/2R or 2R/3RC Decreased TYMS expression Increased 5-FU responsiveness Increased risk of toxicity
	3RG	51% – Chinese 42.7% – Japanese 26-37% – Caucasian, Hispanic, African American	3RG/3RG, 3RG/3RC, or 2R/3RG Increased TYMS expression Decreased 5-FU responsiveness Poor prognosis
	3RC	39.9% – Japanese 30% – Chinese 15-33% – Caucasian, Hispanic, African American	3RG/3RC Increased TYMS expression Decreased 5-FU responsiveness Poor prognosis 3RC/3RC or 2R/3RC Decreased TYMS expression Increased 5-FU responsiveness Increased risk of toxicity
DPD, dihydropyrimidine dehydrogenase

Background

Epidemiology

Incidence (includes colon and rectal cancers) – 40/100,000 (SEER, 2017)
- Sporadic – most common form (~80%)
- Hereditary CRCs
  - HNPCC or Lynch syndrome – accounts for 2-4% of CRC cases in the U.S. (NCCN, Genetic/Familial High Risk Assessment: Colorectal, 2017)
  - FAP – occurs in 1/10,000 live births
    - ~0.5% of total CRC cases
  - MAP – ~1% of Caucasians are predicted to carry an MUTYH gene variant
  - Other inherited syndromes
    - Peutz-Jeghers syndrome (PJS) – 1/200,000
    - Juvenile polyposis syndrome (JPS) – 1/100,000
    - Hereditary diffuse gastric cancer – rare
    - Serrated polyposis syndrome – uncommon
    - Cowden syndrome (PTEN hamartoma syndrome)
    - Li-Fraumeni syndrome – rare
Age
- Sporadic – median is 70 years
- Hereditary – usually <60 years
Sex – M>F

Genetics (Familial Syndromes)

Hereditary syndromes associated with CRC account for >10-15% of all CRCs (American College of Medical Genetics and Genomics [ACMG], 2015)
Hereditary CRC types (NCCN, Genetic/Familial High Risk Assessment: Colorectal, 2017)
- Lynch syndrome (also known as HNPCC)
  - Associated with MSI and MMR gene mutations/modifications – usually MLH1, MSH2, MSH6, PMS2
  - Other genes (MLH3, PMS1, EPCAM, and EXO1) have been identified
- FAP
  - APC gene variants
    - Autosomal dominant inheritance
    - 25% of cases are de novo
  - Syndromes
    - Classic FAP and attenuated FAP forms
    - Gardner syndrome
    - Turcot syndrome
- MAP
  - MUTYH gene variants
    - Autosomal recessive inheritance
    - Two MUTYH variants, Y165C and G382D, account for 85% of MAP in Caucasians
    - Biallelic variants appear to create risk for cancer
- PJS
  - STK11 gene variants
  - Autosomal dominant inheritance
  - 50% of patients do not have this variant
- JPS
  - SMAD4 or BMPR1A gene variants
  - Autosomal dominant inheritance
- Li-Fraumeni syndrome
  - TP53 variant
- Cowden syndrome (PTEN hamartoma tumor syndrome)
  - PTEN gene variants
  - Autosomal dominant with high penetrance
- Other entities include Turcot, Gardner, Muir-Torre, Bannayan-Riley-Ruvalcaba, and serrated polyposis syndromes (NCCN, Genetic/Familial High Risk Assessment: Colorectal, 2017)

Risk Factors

IBD (eg, Crohn disease, ulcerative colitis)
First-degree relative with colorectal adenoma or invasive CRC
Tobacco use
Diet high in animal fats/processed meats (Western diet)
Sedentary lifestyle
Metabolic syndrome
Previous adenoma/sessile serrated polyp (SSP)
Previous radiation
Ureterosigmoidostomy – carcinoma can develop ≥15 years after procedure

Pathophysiology

Most CRCs arise from adenomatous polyps
- Villous adenomas transform into adenocarcinomas more frequently than do tubular adenomas
- Subset of adenocarcinomas develop from hyperplastic-appearing polyps, especially large, right-sided polyps
- Adenocarcinoma arising in a polyp is considered malignant when it penetrates into the submucosa
Other less common tumors can occur (neuroendocrine and mesenchymal tumors, lymphomas)

Clinical Presentation

Common signs and symptoms
- Rectal bleeding
- Hematochezia
- Abdominal pain and bloating
- Tenesmus
- Change in stool (narrowing of caliber)
Symptoms vary with tumor location
- Most tumors are located in sigmoid colon and rectum
- Cecum and ascending colon – tumors may be very large before causing symptoms (obstruction)
  - Anemia – a common presenting symptom
- Descending and transverse colon – tumors tend to obstruct and cause annular lesions (apple core or napkin ring) with abdominal pain and bloating
- Rectosigmoid – hematochezia, tenesmus, and narrowing of stool caliber
Sporadic tumors
- Usually single tumors
Clinical presentation and characteristics of inherited syndromes (NCCN, Genetic/Familial High Risk Assessment: Colorectal, 2017)
- Lynch syndrome
  - May have multiple tumors
  - Median age of onset – 40-60 years (10 years younger than in sporadic colorectal carcinoma)
  - For more information, refer to Lynch syndrome and Lynch syndrome (HNPCC) testing algorithm
- FAP
  - Classic
    - Affected persons develop hundreds to thousands of colon polyps and subsequent CRC
      Often present with multiple tumors
      
      Presence of ≥100 polyps is sufficient for clinical diagnosis (or <100 polyps at younger ages in a family with identified FAP)
    - Median age of onset – 39 years
    - Increased risk for other malignancy – thyroid (papillary cribriform-morular variant), medulloblastoma, hepatoblastoma, pancreas, gastric/duodenal
    - Possible associated findings
      Osteomas – Gardner syndrome
      
      Gastric and duodenal polyps
      
      Dental anomalies
      
      Congenital hypertrophy of the retinal pigment epithelium (CHRPE)
      
      Central nervous system (CNS) tumors – Turcot syndrome
  - Attenuated
    - 10-100 polyps (average is 30), frequently with right-sided distribution
    - Cancer appears at older age than in classic FAP – mean age >50 years
    - Risk of other malignancy similar to that of classic FAP
    - Extraintestinal manifestations of classic FAP are rare
- MAP
  - 100-1,000 polyps (usually <100 polyps)
  - Median age of onset – 45-59 years
  - Often indistinguishable from attenuated FAP – may have similar extraintestinal manifestations or serrated polyposis syndrome (may have serrated polyps)
  - Increased risk for malignancy – duodenal cancer
- PJS
  - Hamartomatous gastrointestinal polyps – tend to be fewer than in FAP
  - Perioral melanin pigmentation, which tends to fade when adulthood reached
  - Increased risk for other malignancy (breast, ovary, pancreas, and gallbladder)
- JPS
  - Juvenile hamartomatous polyps found mainly in colon
  - Usually diagnosed in adolescence
  - Median age – 33 years
- Serrated polyposis syndrome
  - Serrated polyps usually >10 mm
  - Risk for CRC not as high as in other syndromes
- Li-Fraumeni syndrome
  - Lifetime risk of CRC increased
  - Most frequent malignancies are sarcomas, as well as breast, adrenocortical, and brain tumors
- Cowden syndrome
  - Polyps often >50 with various histologies (eg, hyperplastic, adenomatous, hamartomatous)
  - Risk much lower for CRC than FAP or MAP
  - Increased risk for other malignancy (eg, skin, breast, thyroid, endometrial, brain)

ARUP Lab Tests

Tests generally appear in the order most useful for common clinical situations. Click on number for test-specific information in the ARUP Laboratory Test Directory.

Mismatch Repair by Immunohistochemistry 0049302
Method: Qualitative Immunohistochemistry

Recommended Use

First-line screening test for Lynch syndrome

Highly recommended prior to ordering germline MMR mutation analysis gene testing; results direct subsequent genetic diagnostic testing

Determine MMR protein expression (MLH1, MSH2, PMS2, and MSH6) in tumor tissue

Refer to Additional Technical Information document for further content

Limitations

~10% of individuals with Lynch syndrome will have IHC tests that show normal staining of the MMR proteins

Because correlation of MSI with IHC is not 100%, direct testing of MSI by PCR may be helpful

Screens for Lynch syndrome only and does not evaluate other hereditary causes of CRC

Occult Blood, Fecal by Immunoassay 2007190
Method: Qualitative Immunoassay

Recommended Use

Screen for CRC

Microsatellite Instability (MSI), HNPCC/Lynch Syndrome, by PCR 0051740
Method: Polymerase Chain Reaction/Fragment Analysis

Recommended Use

First-line screening test for Lynch syndrome

Directs subsequent genetic diagnostic testing for Lynch syndrome

Refer to Additional Technical Information document for further content

Limitations

15% of sporadic CRCs are also MSI-H

Preoperative chemoradiation of rectal cancer may complicate IHC interpretation and/or decrease tumor mass and make MSI testing difficult; evaluation of pretreatment biopsies will avoid this limitation

Screens for Lynch syndrome only and does not evaluate other hereditary causes of CRC

Epi proColon 2013906
Method: Polymerase Chain Reaction

Recommended Use

Indicated to screen adults of either sex, ≥50 years, defined as having average risk for CRC, who have been offered and have a history of not completing CRC screening

Tests that are available and recommended in the USPSTF 2008 CRC screening guidelines should be offered and declined prior to offering the Epi proColon test

For more information, please refer to the Instructions for Use

Follow-up

Test results should be used in combination with physician's assessment and individual risk factors in guiding patient management

Patients with a positive Epi proColon test result should be referred for diagnostic colonoscopy

Colon Cancer Gene Panel, Somatic 2011616
Method: Mass Spectrometry

Recommended Use

Indicated for individuals with metastatic CRC to guide treatment with anti-EGFR monoclonal antibodies (eg, cetuximab and panitumumab)

Detect mutations in KRAS (codons 12, 13, 61 [MassARRAY also detects codon 146]), BRAF (codon 600), PIK3CA (codons 542, 545, 1047), and NRAS (codons 12, 13, 61)

Refer to Additional Technical Information document for further content

Limitations

Limit of detection – ~10% mutant alleles

Oncogenic mutations outside of codons tested will not be detected

KRAS Mutation Detection with Reflex to BRAF Codon 600 Mutation Detection 2001932
Method: Polymerase Chain Reaction/Pyrosequencing

Recommended Use

Determine eligibility for anti-EGFR (cetuximab and panitumumab) therapy in patients with metastatic CRC

Detect mutations in codons 12, 13, 61

Refer to Additional Technical Information document for further content

Reflex pattern – if KRAS mutation is not detected, BRAF codon 600 mutation detection test will be performed

Limitations

Limit of detection – 10% mutant alleles

Oncogenic mutations outside of codons tested will not be detected

A substantial portion of individuals with wild-type KRAS still fail to respond to anti-EGFR agents, implicating downstream mutations

KRAS Mutation Detection 0040248
Method: Polymerase Chain Reaction/Pyrosequencing

Recommended Use

Predict response to anti-EGFR and MAPK pathway therapies in a variety of malignancies, including CRC

Limitations

Limit of detection – 10% mutant alleles

Oncogenic mutations outside of codons tested will not be detected

A substantial portion of individuals with wild-type KRAS still fail to respond to anti-EGFR agents, implicating downstream mutations

BRAF Codon 600 Mutation Detection by Pyrosequencing 2002498
Method: Polymerase Chain Reaction/Pyrosequencing

Recommended Use

Detect activating BRAF mutations at codon 600, which can indicate resistance to anti-EGFR therapy in CRC

This test is also used within Lynch syndrome reflex testing pathway (for CRC specimens only)

Limitations

Limit of detection – 10% mutant alleles

Oncogenic mutations outside of codon tested will not be detected

BRAF V600E Mutation Detection in Circulating Cell-Free DNA by Digital Droplet PCR 2013921
Method: Polymerase Chain Reaction

Recommended Use

Determine BRAF V600E mutation status in patients with solid tumors to select candidates for targeted therapy with kinase (BRAF and/or MEK) inhibitors

Monitor response to therapy and disease progression in patients carrying BRAF V600E mutation

NRAS Mutation Detection by Pyrosequencing 2003123
Method: Polymerase Chain Reaction/Pyrosequencing

Recommended Use

Predict response to anti-EGFR and MAPK pathway therapies in a variety of malignancies, including CRCs

Detect activating NRAS mutations (codons 12, 13, 61) associated with relative resistance to anti-EGFR therapy

Refer to Additional Technical Information document for further content

Limitations

Limit of detection – 10% mutant alleles

Oncogenic mutations outside of codons tested are not detected

Presence or absence of mutations does not guarantee a response or lack of response to anti-EGFR therapies

Familial Mutation, Targeted Sequencing 2001961
Method: Polymerase Chain Reaction/Sequencing

Recommended Use

Useful when a pathogenic familial variant identifiable by sequencing is known

Consultation with a genetics counselor is advised

Familial Adenomatous Polyposis Panel: (APC) Sequencing and Deletion/Duplication, (MUTYH) 2 Mutations 2004915
Method: Polymerase Chain Reaction/Sequencing/Multiplex Ligation-dependent Probe Amplification

Recommended Use

Preferred diagnostic or predictive test for FAP and MAP

Refer to Additional Technical Information document for further content

Limitations

APC gene – deep intronic or regulatory region variants will not be identified; breakpoints of large deletions/duplications will not be determined

Only two pathogenic MUTYH gene variants will be tested – Y165C and G382D

Diagnostic errors can occur due to rare sequence variations

Carcinoembryonic Antigen 0080080
Method: Quantitative Electrochemiluminescent Immunoassay

Recommended Use

Monitor patient for tumor recurrence

Limitations

Not recommended for screening in the general population

MUTYH-Associated Polyposis (MUTYH) 2 Mutations 2004911
Method: Polymerase Chain Reaction/Sequencing

Recommended Use

Acceptable diagnostic or predictive test for MAP in Northern European Caucasians

For non-Caucasians, refer to MAP (MUTYH) gene sequencing testing

Only two pathogenic MUTYH mutations are tested – c.494A>G (p.Y165C) and c.1145G>A (p.G382D)

Refer to Additional Technical Information document for further content

Limitations

Large deletions or duplications and deep intronic, regulatory region, or promoter pathogenic mutations will not be detected

Diagnostic errors can occur due to rare sequence variations

Circulating Tumor Cell Count 0093399
Method: Immunomagnetic Separation/Immunofluorescent Stain/Computer Assisted Analysis

Recommended Use

Use in metastatic tumors in conjunction with clinical data and imaging to monitor response to therapy and disease progression

May use to predict survival in patients treated for metastatic breast, prostate, and colorectal cancers

Refer to Additional Technical Information document for further content

Limitations

CTC test is not as accurate as imaging in assessing whether a patient has progressive disease

Patients on doxorubicin therapy – allow at least 7 days following administration of dose before testing

Not detected – CTCs that do not express EpCAM; CTCs that express EpCAM but not cytokeratins 8, 18, 19

Serial CTCs should be performed in the same laboratory

MUTYH-Associated Polyposis (MUTYH) 2 Mutations with Reflex to Sequencing 2006307
Method: Polymerase Chain Reaction/Sequencing

Recommended Use

Preferred diagnostic or predictive test for MAP in Caucasians

For non-Caucasians, order MUTYH gene sequencing

Reflex pattern – MUTYH sequencing will be performed if two pathogenic mutations are not identified by targeted testing for Y165C and G382D

Gastrointestinal Hereditary Cancer Panel, Sequencing and Deletion/Duplication, 16 Genes 2013449
Method: Massively Parallel Sequencing/Exonic Oligonucleotide-based CGH Microarray/Sequencing/Multiplex Ligation-dependent Probe Amplification

Recommended Use

Confirm a diagnosis of hereditary gastrointestinal (GI) cancer in individuals with a personal or family history of GI cancer and/or polyposis

Includes all four MMR genes known to cause Lynch syndrome

Preferred test for individuals with suspected Lynch syndrome or another hereditary GI cancer syndrome

Analysis of specific genes included in this panel may be available individually at ARUP

Genes included – APC, BMPR1A, CDH1, EPCAM, MLH1, MSH2, MSH6, MUTYH, PMS2, PTEN, SDHB, SDHC, SDHD, SMAD4, STK11, TP53

Refer to Additional Technical Information document for further content

Limitations

Diagnostic errors can occur due to rare sequence variations

Not determined or evaluated – Variants in genes not included on the panel; deep intronic and regulatory region variants; breakpoints for large deletions/duplications; sequence changes in EPCAM gene

Deletions/duplications may not be detected in exon 9 in BMPR1A gene; exon 1 in CDH1 and MSH2 genes; exon 8 in PMS2 gene; exons 4, 6, and 7 in STK11 gene

Individuals with hematological malignancy and/or a previous allogenic bone marrow transplant should not undergo molecular genetic testing on peripheral blood specimen; testing of cultured fibroblasts or buccal specimen is required for accurate interpretation of test results; not all predisposing genes are analyzed

Medical Reviewers

Bayrak-Toydemir, Pinar, MD, PhD, Medical Director, Molecular Genetics and Genomics at ARUP Laboratories; Associate Professor of Clinical Pathology, University of Utah

Chidsey, Brandalyn A., MS, LCGC, Genetic Counselor, Biochemical and Molecular Genetics at ARUP Laboratories

Matynia, Anna P., MD, Medical Director, Solid Tumor Molecular Diagnostics, at ARUP Laboratories; Assistant Professor of Clinical Pathology, University of Utah

Velden, Sara, MS, LCGC, Genetic Counselor, Molecular Genetics and Cytogenetics at ARUP Laboratories

References

Guidelines

Protocol for the Examination of Specimens from Patients with Primary Carcinoma of the Colon and Rectum. Based on AJCC/UICC TNM, 7th ed. Protocol web posting date: Jan 2016. College of American Pathologists (CAP). Northfield, IL [Revised: Jan 2016; Accessed: May 2018]
American Cancer Society Guidelines for the Early Detection of Cancer. American Cancer Society. Atlanta, GA [Revised: May 2018; Accessed: May 2018]
NCCN Clinical Practice Guidelines in Oncology, Colon Cancer. Version 2.2018. National Comprehensive Cancer Network. Fort Washington, PA [Updated: Mar 2018; Accessed: Apr 2018]
NCCN Clinical Practice Guidelines in Oncology, Colorectal Cancer Screening. Version 1.2018. National Comprehensive Cancer Network. Fort Washington, PA [Updated: Mar 2018; Accessed: Apr 2018]
NCCN Clinical Practice Guidelines in Oncology, Genetic/Familial High-Risk Assessment: Colorectal. Version 3.2017. National Comprehensive Cancer Network. Fort Washington, PA [Updated: Mar 2017; Accessed: Apr 2018]
Stoffel EM, Mangu PB, Gruber SB, Hamilton SR, Kalady MF, Lau MW, Lu KH, Roach N, Limburg PJ, American Society of Clinical Oncology, European Society of Clinical Oncology. Hereditary colorectal cancer syndromes: American Society of Clinical Oncology Clinical Practice Guideline endorsement of the familial risk-colorectal cancer: European Society for Medical Oncology Clinical Practice Guidelines. J Clin Oncol. 2015; 33(2): 209-17. PubMed
Choosing Wisely. An initiative of the ABIM Foundation. [Accessed: Jun 2018]
Hampel H, Bennett RL, Buchanan A, Pearlman R, Wiesner GL, Guideline Development Group, American College of Medical Genetics and Genomics Professional Practice and Guidelines Committee and National Society of Genetic Counselors Practice Guidelines Committee. A practice guideline from the American College of Medical Genetics and Genomics and the National Society of Genetic Counselors: referral indications for cancer predisposition assessment. Genet Med. 2015; 17(1): 70-87. PubMed
Lin JS, Piper MA, Perdue LA, Rutter CM, Webber EM, O'Connor E, Smith N, Whitlock EP. Screening for Colorectal Cancer: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force. JAMA. 2016; 315(23): 2576-94. PubMed
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Rex DK, Johnson DA, Anderson JC, Schoenfeld PS, Burke CA, Inadomi JM, American College of Gastroenterology. American College of Gastroenterology guidelines for colorectal cancer screening 2009 [corrected]. Am J Gastroenterol. 2009; 104(3): 739-50. PubMed
Wilt TJ, Harris RP, Qaseem A, High Value Care Task Force of the American College of Physicians. Screening for cancer: advice for high-value care from the American College of Physicians. Ann Intern Med. 2015; 162(10): 718-25. PubMed
Rex DK, Boland R, Dominitz JA, Giardiello FM, Johnson DA, Kaltenbach T, Levin TR, Lieberman D, Robertson DJ. Colorectal Cancer Screening: Recommendations for Physicians and Patients from the U.S. Multi-Society Task Force on Colorectal Cancer. Am J Gastroenterol. 2017; 112(7): 1016-1030. PubMed
Sepulveda AR, Hamilton SR, Allegra CJ, Grody W, Cushman-Vokoun AM, Funkhouser WK, Kopetz SE, Lieu C, Lindor NM, Minsky BD, Monzon FA, Sargent DJ, Singh VM, Willis J, Clark J, Colasacco C, Rumble B, Temple-Smolkin R, Ventura CB, Nowak JA. Molecular Biomarkers for the Evaluation of Colorectal Cancer: Guideline Summary From the American Society for Clinical Pathology, College of American Pathologists, Association for Molecular Pathology, and American Society of Clinical Oncology. J Oncol Pract. 2017; 13(5): 333-337. PubMed
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General References

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Bénard F, Barkun AN, Martel M, von Renteln D. Systematic review of colorectal cancer screening guidelines for average-risk adults: Summarizing the current global recommendations. World J Gastroenterol. 2018; 24(1): 124-138. PubMed

Chua W, Moore MM, Charles KA, Clarke SJ. Predictive biomarkers of clinical response to targeted antibodies in colorectal cancer. Curr Opin Mol Ther. 2009; 11(6): 611-22. PubMed

Colle R, Cohen R, Cochereau D, Duval A, Lascols O, Lopez-Trabada D, Afchain P, Trouilloud I, Parc Y, Lefevre JH, Fléjou J, Svrcek M, André T. Immunotherapy and patients treated for cancer with microsatellite instability. Bull Cancer. 2017; 104(1): 42-51. PubMed

Cunningham D, Atkin W, Lenz H, Lynch HT, Minsky B, Nordlinger B, Starling N. Colorectal cancer. Lancet. 2010; 375(9719): 1030-47. PubMed

deVos T, Tetzner R, Model F, Weiss G, Schuster M, Distler J, Steiger KV, Grützmann R, Pilarsky C, Habermann JK, Fleshner PR, Oubre BM, Day R, Sledziewski AZ, Lofton-Day C. Circulating methylated SEPT9 DNA in plasma is a biomarker for colorectal cancer. Clin Chem. 2009; 55(7): 1337-46. PubMed

Fearon ER. Molecular genetics of colorectal cancer. Annu Rev Pathol. 2011; 6: 479-507. PubMed

Hegde M, Ferber M, Mao R, Samowitz W, Ganguly A, Working Group of the American College of Medical Genetics and Genomics (ACMG) Laboratory Quality Assurance Committee. ACMG technical standards and guidelines for genetic testing for inherited colorectal cancer (Lynch syndrome, familial adenomatous polyposis, and MYH-associated polyposis). Genet Med. 2014; 16(1): 101-16. PubMed

Impact of primary (1º) tumor location on overall survival (OS) and progression-free survival (PFS) in patients (pts) with metastatic colorectal cancer (mCRC): Analysis of CALGB/SWOG 80405 (Alliance). J Clin Oncol. 34, 2016 (suppl; abstr 3504) [Accessed: May 2018]

Liu Z, Zhang Y, Niu Y, Li K, Liu X, Chen H, Gao C. A systematic review and meta-analysis of diagnostic and prognostic serum biomarkers of colorectal cancer. PLoS One. 2014; 9(8): e103910. PubMed

Newton KF, Newman W, Hill J. Review of biomarkers in colorectal cancer. Colorectal Dis. 2012; 14(1): 3-17. PubMed

Ross JS. Clinical implementation of KRAS testing in metastatic colorectal carcinoma: the pathologist's perspective. Arch Pathol Lab Med. 2012; 136(10): 1298-307. PubMed

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Song L, Li Y. SEPT9: A Specific Circulating Biomarker for Colorectal Cancer. Adv Clin Chem. 2015; 72: 171-204. PubMed

Venook AP. Metastatic Colorectal Cancer: Lessons Learned, Future Possibilities. J Natl Compr Canc Netw. 2016; 14(5 Suppl): 666-8. PubMed

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Yurgelun MB, Goel A, Hornick JL, Sen A, Turgeon DK, Ruffin MT, Marcon NE, Baron JA, Bresalier RS, Syngal S, Brenner DE, Boland R, Stoffel EM. Microsatellite instability and DNA mismatch repair protein deficiency in Lynch syndrome colorectal polyps. Cancer Prev Res (Phila). 2012; 5(4): 574-82. PubMed

References from the ARUP Institute for Clinical and Experimental Pathology^®

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Affolter K, Samowitz W, Tripp S, Bronner MP. BRAF V600E mutation detection by immunohistochemistry in colorectal carcinoma. Genes Chromosomes Cancer. 2013; 52(8): 748-52. PubMed

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Patil DT, Bronner MP, Portier BP, Fraser CR, Plesec TP, Liu X. A five-marker panel in a multiplex PCR accurately detects microsatellite instability-high colorectal tumors without control DNA. Diagn Mol Pathol. 2012; 21(3): 127-33. PubMed

Pellatt DF, Stevens JR, Wolff RK, Mullany LE, Herrick JS, Samowitz W, Slattery ML. Expression Profiles of miRNA Subsets Distinguish Human Colorectal Carcinoma and Normal Colonic Mucosa. Clin Transl Gastroenterol. 2016; 7: e152. PubMed

Salk JJ, Bansal A, Lai LA, Crispin DA, Ussakli CH, Horwitz MS, Bronner MP, Brentnall TA, Loeb LA, Rabinovitch PS, Risques RA. Clonal expansions and short telomeres are associated with neoplasia in early-onset, but not late-onset, ulcerative colitis. Inflamm Bowel Dis. 2013; 19(12): 2593-602. PubMed

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	Colorectal Cancer. ARUP Consult^©. Retrieved July 20, 2018, from: https://arupconsult.com/content/colorectal-cancer

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Colorectal Cancer

Diagnosis

Indications for Testing

Laboratory Testing

Histopathology

Prognosis

Differential Diagnosis

Screening

Monitoring

Pharmacogenetics

Background

Epidemiology

Genetics (Familial Syndromes)

Risk Factors

Pathophysiology

Clinical Presentation

ARUP Lab Tests

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General References

References from the ARUP Institute for Clinical and Experimental Pathology®

References from the ARUP Institute for Clinical and Experimental Pathology^®