Genetic Contribution to CRC in Older Patients

1
Genetic Contribution to CRC in Older Patients

• Dan Fontaine Roger Green
  Jane Green
• Barbara Smith

2
Age-Standardized Incidence Rates for Colorectal
Cancer.
Rate per 100,000
Canada
NL
ON
BC
Males
62
82
61
54
Females
41
51
42
37
Total
103
133
102
91
3
(No Transcript)
4
Why are the numbers of high- and intermediate-
risk cases so high in Newfoundland?
Possible explanations

• The Newfoundland cohort excluded cases age 75
  years and older.
• It is believed that inherited CRC cases occur
  more frequently in younger patients than in older
  ones.
• Thus the incidence of familial cancers in the NF
  and ON cohorts could be artificially high.

5
Objective
Genetic Contribution to CRC in Older Patients

• To determine the genetic contribution to CRC in
  patients age75 and older.

6
Genetic contribution to colorectal cancer in
older patients.

• Objective
• To assess the family risk status of Newfoundland
  CRC patients age gt74y who were diagnosed between
  1999 and 2003.
• Is the family risk profile of older patients the
  same as that for younger patients?
• Methods
• Family history questionnaire.
• Tumour analysis

7
The Plan

• Contact patients or proxies of the 623 NL cases
  diagnosed at gt74y.
• Obtain ROI, access to tumour blocks.
• Family history questionnaire.
• No blood, PHQ or FFQ requested.
• Participation of the patient not essential.
• All information can be obtained from proxy.

8
The Plan

• Assess familial risk
• FAP, Amsterdam I and II
• Bethesda criteria
• ACMAC criteria
• Affected first degree relatives
• Tumour analysis
• MSI, IHC, methylation, BRAF status.

9
Timelines (as of June 2007)

• Complete ascertainment. 12 months
• Pedigrees, med records,
• risk assessment. 18 months
• Collect blocks
• IHC, MSI, meth, BRAF 2 yrs

10
Diagnosed Jan 2002-Dec 2006 Age gt74
677 Cases from Tumour Registry
Of 517 Contacted
11
(No Transcript)
12
Under 75 population
13
Preliminary data, over 75yrs
Pedigrees drawn 229 Risk assessed 166
Pedigree assessment
First-degree relative
14
(No Transcript)
15
all ages
lt75
lt75
Newfoundland 75 30.0
(preliminary)