genetics and primary care familial cancer risk assessment colorectal cancer

Genetics and Primary Care

Familial Cancer Risk Assessment

Colorectal Cancer

Case 1:Joan

• Joan, age 38, was recently diagnosed with endometrial cancer. Family history reveals:

– Paternal grandmother: endometrial cancer, age 50 – Paternal uncle: colon cancer, age 48 – Father: colonoscopy at age 50; four adenomatous

polyps removed

– No other significant history – Both sides of the family are Northern European

Caucasian

Case 2: Ted

• Ted is 30 and wants a colonoscopy because his mother was just diagnosed with colon cancer after routine screening at age 54. Family history reveals:

– Paternal grandfather: died of CRC at age 79

– No hx of endometrial, ovarian, small bowel or ureter/kidney cancer on either side of family

– Two maternal aunts: cervical cancer at ages 30 & 34

– Maternal grandmother: breast cancer age 85

Outline

• Hereditary colorectal cancer syndromes

• Cancer family history – a primary tool

• Evaluating your patients for familial CRC risk

• Genetic counseling and testing for hereditary colorectal cancer

• How, when, where to refer patients for genetic services

Colorectal Cancer

• ~5-8% of all cases of CRC are hereditary

• ~15-20% are “familial” / multifactorial

• ~75% of cases are sporadic

Feuer EJ: DEVCAN: National CA Inst. 1999

Characteristics of Average Risk

• No well-defined threshold between sporadic and familial CRC at this time

• Probably safe to include individuals with:

– No personal risk factors or family history of CRC

– One 2nd or 3rd degree relative with CRC >60 years with no other family history of CRC

Characteristics of “Familial” CRC

• “Clustering” of colon cancer cases in the family (> 50 at diagnosis) without clear dominant pattern, or

• One close relative with CRC <60 yrs and family history does not meet criteria for known hereditary CRC syndromes

• Likely to be multiple low pentrant genes plus environmental factors at play

• Family members warrant earlier CRC screening

– Starting at 40 years or 5-10 yrs earlier than age of diagnosis of the youngest affected relative

Winawer et al., Gastroenterology 2003:124:544-560

Characteristics of Hereditary CRC

• Multiple relatives with colorectal cancer

– One or more diagnosed at an early age (<50)

• Sequential generations affected

– Except in autosomal recessive syndromes

• Other cancers in the family known to be associated with CRC (uterine, ovarian, GI)

• Multiple primary tumors or polyps

Hereditary CRC syndromes

• Hereditary Non-Polyposis Colorectal Cancer (HNPCC)– Variants: Muir-Torre, Turcot

• Familial Adenomatous Polyposis (FAP)– Variants: Gardner, Turcot

– Attenuated FAP

– APC mutation in Ashkenazi Jews

• Others: – Multiple adenomatous polyposis syndrome/MYH gene (MAP)

– Peutz-Jeghers syndrome (PJS)

– Familial Juvenile Polyposis (FJP)

In Your Practice: Colon Cancer

• In the typical primary care practice, 2 to 8 patients (1/200 to 1/800) are from “high risk” families, with a condition called Hereditary Non-Polyposis Colon Cancer (HNPCC). These patients have a high lifetime risk of colorectal and other cancers with risk starting in their 20’s.

HNPCC: AKA “Lynch syndrome”

• 2-3% of all colorectal cancer cases

• Autosomal dominant; high penetrance

• Typical age of CA onset is 40-50 yrs

• Multiple affected generations

• 60-70% right-sided/proximal CRC tumors

• Polyps may be present, multiple primaries common. Can overlap with AFAP

HNPCC

• Lifetime cancer risks: – Colorectal 80%

– Endometrial 20-60% – Gastric 13-19%– Ovarian 9-12%– Biliary tract 2%– Urinary tract 4%– Small bowel 1-4%– Brain/CNS 1-3%

HNPCC: Clinical Diagnostic Criteria

• Amsterdam II Criteria (3-2-1 rule)

– 3 or more relatives with an HNPCC-related cancer, one of whom is a 1st degree relative of the other two

– 2 or more successive generations affected

– 1 or more cancers diagnosed before age 50

HNPCC

• Caused by mutations or deletions in mismatch repair (MMR) genes

– MSH2, MLH1, MSH6, (PMS2)

– 90% of detectable mutations in MSH2 and MLH1

• 50% of families meeting Amsterdam II Criteria have detectable mutations

• Testing/screening options:

– Direct genetic testing of MMR genes (in select families)

– Initial screening of the tumor tissue by MSI/IHC

Proceed Directly To Genetic Testing After genetic counseling and informed consent!

IF:

• Family history fulfills Amsterdam II criteria or

• Patient has two HNPCC related cancers or

• Patient has CRC and a 1st degree relative with HNPCC-related cancer, with at least one cancer diagnosed <50 years of age

• Always test an affected family member first!

MSI/IHC screening

• Microsatellite Instability (MSI) on tumor tissue

– can be used to screen for HNPCC in select cases

• Immunohistochemistry (IHC) on tumor tissue

– can be used to detect the presence or absence of the mismatch repair proteins (MSH2, MLH1, etc.)

• “Screen positive” individuals can be offered cancer genetic counseling/assessment and targeted genetic testing

Criteria for MSI/IHC screening

Revised Bethesda Criteria, 2004• CRC or endometrial CA <50 yrs

• 2 HNPCC cancers in same person

• CRC with “MSI-H histology” diagnosed <60 yrs

– Infiltrating lymphocytes, Crohns-like lymphocytic reaction, mucinous/signet ring differentiation, medullary growth pattern

• CRC and one or more 1st degree relative with an HNPCC-related cancer, one diagnosed <50 yrs

• CRC and two or more 1st or 2nd degree relatives with HNPCC-related cancers, any age

Umar A et al: J Natl Cancer Inst, 2004; 96(4):261-268

HNPCC Surveillance

• Gene carriers or at-risk relatives:– CRC: colonoscopy age 20-25, repeat 1-2 yrs– Women: gyn exam, endometrial aspiration, TV U/S,

CA-125 (?) age 25-35, repeat 1-2 yrs

• If one HNPCC family member affected w/the following:– Stomach CA: EGD age 3-35, repeat 1-2 yrs– Urinary tract CA: urine cytology age 30-35, repeat 1-2

yrs

NCCN practice guidelines in oncology – v.1.2003

FAP

• 1 in 10,000 incidence

• 100’s to 1000’s of colonic adenomas by teens

– Cancer risk: colon, gastric, duodenum (periampulla), small bowel, pancreas, papillary thyroid, childhood hepatoblastoma

• 7% risk of CRC by 21 yrs; 93% by 50 yrs

• Autosomal dominant: APC gene mutations

• Variants: Gardner, Turcot

FAP – surveillance

• Colon– Annual sigmoidoscopy, age 10-12 yrs– Prophylactic colectomy following polyp detection

w/continued surveillance of rectum, ileal pouch• Duodenal/gastric

– EGD age 25, repeat 1-3 yrs• Thyroid

– Annual PE, age 10• Hepatoblastoma

– Annual screen by abd U/S & AFP from birth to 5 yrs.

Gastroenterology 2001; 121: 195. AGA Statement

Attenuated FAP

• 20 to 100 polyps, usually more proximal

– Onset later than FAP, average AOO = 50

– Lifetime risk of CRC = 80%

• Extracolonic tumors occur at same rate as FAP

• Variant of FAP, mutations in same APC gene

• Surveillance:

– annual colonoscopy starting late teens or early 20’s

– Option of subtotal colectomy

Genetic Testing: FAP/AFAP

• Test an affected family member first!

– After genetic counseling and informed consent

• APC gene testing can confirm a suspected diagnosis

• Family members of a person with a known APC mutation can have mutation-specific testing

• Genetic testing for children at risk for FAP can be considered before beginning colon screening

APC gene mutation in Ashkenazi Jews

• Missense mutation (I1307K) associated with increased risk of CRC and adenomas in Ashkenazi Jews (AJ)

• Found in 6% of the general AJ population

– 12% of AJs with CRC

– 29% of AJs with CRC and a positive family history

• Lifetime risk of CRC in mutation carrier is 10-20%

• Screening: colonscopy every 2-5 yrs starting at 35 yrs

MAP syndrome/MYH gene

• Multiple adenomatous polyposis (MAP) syndrome

– Autosomal recessive; mutations in the MYH gene

– Median number of polyps = 55

– Mean age of polyp diagnosis = 30-50 years

– Polyps mainly small, mildly dysplastic tubular adenomas. Some tubulovillous, hyperplastic, serrated adenomas, microadenomas

• 30% of individuals with 15-100 polyps have homozygous mutations in the MYH gene

• Genetic testing should be offered if >15 polyps (and APC gene testing negative)

Peutz-Jeghers syndrome

• <1% of all CRC cases

• Hamartomatous polyps of GI tract as early as 1st decade

• Mucocutaneous hyperpigmentation – lips, mouth, buccal mucosa, fingers

– Usually seen in children < 5 yrs

• Cancer risk: – colon, small intestine, stomach, pancreas,

breast, ovaries, uterus, testes, lungs, kidneys

• Mutations in STK11 gene – found in 70% of familial cases and 30-70% of

sporadic cases

Familial Juvenile Polyposis

• <1% of all CRC cases

• Autosomal dominant

• 5 or more juvenile polyps in colon or GI tract

– Appear in 1st or 2nd decade

– 50% lifetime risk of CRC; AOO in 30’s

– Increased risk gastric, GI, pancreatic CA

• ~50% of cases have mutations in either the MADH4 or BMPR1A genes

What can YOU do?

CRC Risk Screening: Steps to take

1. Take a thorough cancer family history

2. Does family history meet hereditary criteria?

– If yes, refer to genetics

3. Classify based on family history: average, moderate or high risk.

– Create surveillance plan based on risk level

Family Health History

“The family tree has become the most important genetic test of all. The more you know, the more tools you have to practice preventive medicine”

Donna Russo, Certified Genetic Counselor, NY Presbyterian-Columbia Hospital

Family History Details to Record

• Type of primary cancer(s) in each relative

• Age of disease onset in each relative

• Cancer status in 1st and 2nd degree relatives

• Cancer status in both sides of the family

• Other medical findings



2. Does family history meet ‘potentially hereditary’ criteria?




Consider Genetics Referral for:

• Two or more family members with CRC* at least one <50

• Three or more family members w/CRC*; any age

• Patient with colon cancer before 40 yrs

• Endometrial cancer and family history of CRC <50

• Persons with more than one primary CRC <50 yrs or with both endometrial CA and CRC

• Family or personal history of CRC and one or more 1st degree relative with an HNPCC-related cancer, one diagnosed <50 yrs.

*Same side of family

Consider Genetics Referral for:

• MSI and/or IHC tumor results suspicious for HNPCC

• Autosomal dominant pattern of cancers in the family

• Persons with 15 or more adenomatous colorectal polyps

• Persons with multiple hamartomatous or juvenile GI polyps

• Persons with a family history of a known hereditary cancer syndrome



2. Does family history meet hereditary criteria?




Empiric Risk of CRC

• Risk for CRC based on family history increases with:

– Closer degree of relationship and # of affected members

– Younger age of onset

– Presence of extracolonic tumors, multiple primaries

Family History: Empiric Risks

Lifetime Risk CRC

General population in US ~2 to 6%

One 1st degree relative w/CRC 2-3 fold

Two 1st degree relatives w/CRC 3-4 fold

1st degree relative w/CRC <50 3-4 fold

One 2nd or 3rd degree relative w/CRC ~1.5-fold

Two 2nd degree relatives w/CRC 2-3 fold

Goal: Classification

Family Hx

Assessment

Personalized prevention recommendations

Referral for genetic evaluationwith personalized preventionrecommendations

Standard preventionrecommendations

Intervention

Average

Moderate(“Familial”)

High/Genetic

Risk Classification

CRC Risk Management

Age to Begin Average Risk 50 yrs

1. No family history CRC OR

2. One 2nd or 3rd degree relative with CRC

- FOBT annually + Flex sig every 5 yrs; OR

- Colonoscopy every 10 yrs; OR

- DCBE every 5 yrs

CRC Risk Management

Moderate/Family history Age to begin

1. Two 1st degree relatives with CRC any age 40 years*

or one 1st degree relative with CRC < 60

- Colonoscopy every 5 yrs

2. One 1st degree relative with CRC >60 or 40 years

two 2nd degree relatives with CRC any age

- Average risk screening

* Or 5-10 yrs earlier than earliest case in family

Gastroenterology: 2003;124:544-560

CRC Risk Management

Age to Begin

HNPCC or suspected HNPCC 20-25 yrs

1. Colonoscopy every 1-2 yrs

2. Genetic counseling; consider genetic testing

FAP or suspected FAP 10-12 yrs

1. Flex sig or colonoscopy every1-2 yrs

2. Genetic counseling; consider genetic testing

Cancer Genetic Counseling

• Full pedigree analysis and risk assessment

• Discussion of:

– Personal cancer risks based on family history

– Genetic testing options and risk of mutation

– Advantages, risks and limitations of genetic testing

– Personalized, risk-based screening and prevention options

– Support resources

Cancer Genetic Testing: Elements of Informed Consent

• Information on specific test(s) being considered

• Implications of positive, negative, uninformative results

• Options for risk assessment and management without genetic testing

• Risk of passing a mutation to offspring

• Technical accuracy of test

• Fees involved in testing and counseling

• Option of DNA banking

Cancer Genetic Testing: Informed Consent (cont.)

• Psychological implications of test results

• Risks of insurance/employment discrimination

• Confidentiality issues

• Options for and limitations of medical surveillance and strategies for prevention following testing

• Importance of and guidance on sharing results with at-risk relatives

• Results disclosure

American Society of Clinical Oncology, March, 2003

Case 1:Joan

• Joan, age 38, was recently diagnosed with endometrial cancer. Family history reveals:

– Paternal grandmother: endometrial cancer, age 50 – Paternal uncle: colon cancer, age 48 – Father: colonoscopy at age 50; four adenomatous

polyps removed – No other significant history – Both sides of the family are Northern European

Caucasian

Pedigree: Case 1

Key:

Endometrial CA

Colorectal CA

Adenomatous polyps

Dx 38

Dx 50

88 yr

63 yr

4 polyps50 yrs.

CRC Dx 48

61 yr

38 yr

10 yr 8 yr

35 yr

French, Irish, Scottish German, English

Case 1: Assessment

• Joan meets Amsterdam II Criteria and is at risk for HNPCC

• Refer to genetics for cancer genetic counseling and discussion of genetic testing for HNPCC

– Testing options:

• Direct gene testing of MLH1 and MSH2 OR

• MSI/IHC screening of tumor tissue with gene sequencing if MSI positive

Case 2: Ted

• Ted is 30 and wants a colonoscopy because his mother was just diagnosed with colon cancer after routine screening at age 54. Family history reveals:

– Paternal grandfather: died of CRC at age 79.

– No hx of endometrial, ovarian, small bowel or ureter/kidney cancer on either side of family.

– Two maternal aunts: cervical cancer at ages 30 & 34

– Maternal grandmother: breast cancer age 85

Case 2: Pedigree

30 yrs34 yrs

Key:

CRC

Breast CA

Cervical CA

BrCa 85 yrsd.87

Colon Ca54 yrs

Cerv.Ca 30 yr

55 58

Cerv.Ca 32 yr

60

d. 58MI

84

56

CRC 79d.82

Italian Irish German

Case 2: Ted

• Verify Diagnoses! Obtain and review pathology reports on all reported cancers, whenever possible

• If diagnoses are correct: Ted has no family history indicative of a known colon cancer syndrome (HNPCC, FAP, other)

– Ted’s lifetime risk of colorectal CA is increased 2 to 3 fold due to one affected first degree relative (>50)

– Moderate/familial risk: Screening by colonoscopy starting at age 40, or 10 yrs earlier than earliest case in family, is reasonable

Oregon Genetics Providers

• Portland– Oregon Health & Science University – Legacy Health Care– Northwest Perinatal Services– Kaiser-Permanente

• Eugene– Center for Genetics & Maternal Fetal Medicine

• Bend– Genetic Counseling of Central Oregon (cancer only)

Referral for Genetic Services

• Consult “Genetic Services Contact List”

• Phone consultations available:

– OHSU Genetics Consult Line: 503-494-5516

• Refer patients by phone, fax, mail, or patient self-referral

• ‘Indications for Referral’ in resource packet

– Preconception/Prenatal

– Pediatric

– Adolescent/Adult

Resource Materials

• Patient pamphlets:

– ‘Do You Have Cancer in Your Family?’

– ‘Genetic Testing: A Fact Sheet’

• Web-based cancer genetics resource list

• Hereditary Colon Cancer Association

– www.hereditarycc.org

• Resource materials at www.healthoregon.org/genetics

• Genetics tutorials on www.modimes.org

genetics and primary care familial cancer risk assessment colorectal cancer

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