Bowel cancer a family affair
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Bowel cancer - A family affair. Alice Christian Genetic Associate C&SRGS. Identification of a familial mutation may lead to the identification of many relatives at risk. Hereditary Cancers. How to spot an inherited cancer What to do about it Surveillance Referral pathways.

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Bowel cancer - A family affair

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Bowel cancer- A family affair

Alice Christian

Genetic Associate


Identification of a familial mutation may lead to the identification of many relatives at risk

Hereditary Cancers

  • How to spot an inherited cancer

  • What to do about it

    • Surveillance

    • Referral pathways

Family history is the key

  • 3 generation pedigree

  • All cancers noted

  • Ages at diagnosis

Features of Hereditary Cancer

  • More cancer than expected in the family

  • Types of cancer are consistent, or fit a known hereditary cancer pattern

  • Early age of onset (<55 with Fhx or very young with no Fhx)

  • Multiple primary tumours in an individual

  • Presence of unusual cancers or other features – eg. Skin lesions, CHRPES



Colon - 56yrs

Colon - 50 yrs

Endometrial - 50yrs

Urinary tract - 60yrs

Colon - 56yrs

Endometrial - 60yrs

Ovarian - 45yrs

Colon - 50 yrs

Lynch syndrome (Hereditary Non-Polyposis Colorectal Cancer (HNPCC) )

Increased risk for:

  • Colon cancer ~ up to an 80% lifetime risk

  • Endometrial cancer ~30-60% lifetime risk

  • Ovarian cancer ~ 10% lifetime risk

  • Other cancers e.g. gastric, hepatobiliary, kidney, urinary tract, small bowel cancer

  • Sebaceous adenomas

Familial Adenomatous Polyposis (FAP)

  • Adenomatous polyps in colon and rectum

  • Colorectal cancer, usually by age 40

  • Increased chance for some other malignancies:

    • duodenum, stomach, brain, papillary thyroid cancer in young women, ?hepatoblastoma in young children


  • Familial adenomatous polyposis (FAP) is diagnosed clinically in an individual with:

  • Greater than 100 colorectal adenomatous polyps OR

  • Fewer than 100 adenomatous polyps AND a relative with FAP

Adenomatous Polyps in Colon


Other Features

  • Benign desmoid tumors

  • Dental anomalies

  • Epidermoid cysts (esp. scalp)

  • Retinal lesions (CHRPE)

  • Osteomas of the mandible

  • Variable presentation, even within the same family

Congenital hypertrophy of the retinal pigment epithelium (CHRPE) - FAP

Mucocutaneous hyperpigmentation is associated with Peutz-Jegher syndrome. May be subtle and fade with age

What to do?

*Guidelines only – must be flexible!

** due for review

  • Risk may be up to 2x that of the general population

  • Most of this additional risk from 60 years of age

  • If considering one-off screening for reassurance

  • – 50yrs for men, 55 for women.

Moderate risk 3-6 times population risk.

Surveillance for moderate risk group

  • Surveillance – 5 yearly, from 50 (or 10 years before youngest diagnosis)

  • Unlikely to be available through the public system

  • Available through private system

  • Other alternatives may be more accessible:

    • Faecal occult blood (evidence for popn risk)

    • CT colonography

Who should be referred for assessment of family history?

  • Known cancer syndrome in the family

  • Fit “high risk criteria”

  • Problematic “moderate risk”

Where to refer?

  • Genetic services

  • NZ familial GI registry

New Zealand Genetic Services Clinic Locations




& Southern


NZ Familial GI Cancer Registry

  • Provide assessment for familial gastrointestinal cancer syndromes

  • Facilitate ongoing surveillance for at-risk family members

  • Gatekeepers for colonoscopy

  • Funding recently extended to allow a national service

Registry locations

  • Auckland hospital

  • Christchurch hospital

  • Proposed Wellington site by 2011 - 2012

Registry pathway:

  • Refer families for assessment by the registry

  • All cancers confirmed where possible (30% concordance between family history given to GP, and confirmed history)

  • Surveillance guidelines provided based on family history. High risk families enrolled in registry for ongoing management.

  • Families identified as having a likely familial cancer syndrome are referred to genetic services.

  • Genetic services offer genetic testing.

  • Outcome shared with registry who establish appropriate management

  • Genetic services meet with extended family for predictive testing of identified mutations

Genetic Testing Limitations

  • Mutations detected in minority of families

  • Requires blood from living affected relative

  • Lengthy and expensive process

  • Predictive test gives no information on if, when or what type of cancer an individual will develop

  • Sporadic cancer occurs within cancer syndrome families.


  • Family history is the key

  • If looks familial refer to genetic services or Familial GI registry

  • In terminal patients store DNA if there is any chance it is familial (EDTA 20mls)

  • Ring if you have any queriesor not sure whether to refer or not.


0508 364 436

  • (04) 3855310 or ext 5310

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