1 Genetic Testing for Melanoma Risk Stratification Sancy Leachman, MD, PhD Assistant Professor Huntsman Cancer Institute and the Department of Dermatology University of Utah Health Sciences Center Pacific Dermatologic Association August 9, 2008
1
Genetic Testing for Melanoma Risk Stratification
Sancy Leachman, MD, PhDAssistant Professor
Huntsman Cancer Institute and the Department of Dermatology
University of Utah Health Sciences Center
Pacific Dermatologic AssociationAugust 9, 2008
2
Hereditary Melanoma Nevus Phenotype: Lots and Atypical
3
Hereditary MelanomaNevus Phenotype: Many, Mainly Small
4
Hereditary MelanomaNevus Phenotype: Few, Few/No Atypical
Phenotype ≠ Genotype
5
Other Phenotypic Markers“Constitutional” Risk
6
Wild-Type and Homozygous “R” Variant MC1R
7
Heterozygous for MC1R Variants
Phenotype ≠ Genotype
8
Risk EstimationFamily History is Greatest Risk
• Member of melanoma family 35 – 70
• Previous primary melanoma 8.5
• Multiple nevi/atypical nevi 2 – 12
• Red hair 2.4 – 4
• Family history of melanoma 2 – 3
• History of blistering sunburn 2 – 3
• Freckling 2-3
• Blue eyes 1.6
• Skin type I 1.4
FactorFactor Relative RiskRelative Risk
Kefford RF, et al. J Clin Oncol. 1999;17:3245-3251.
9
*Bishop DT et al. J Natl Cancer Inst. 2002;94:894-903. †Rulyak SJ et al. Cancer. 2003;98(4):798-804; and Paker JF et al. Arch Dermatol. 2003;139:1019-1025.
p16 Mutation Carriers:Melanoma and Pancreatic Adenocarcinoma
● p16 Tumor Suppressor controlling the cell cycle
● Higher lifetime risk of melanoma*– United Kingdom: 58%– United States: 76%– Australia: 91%
● Increased risk of pancreatic cancer†
– (11%-17% in some families)
● Red hair increases risk
10
Few Melanomas Are Hereditary
11
Case Presentation● A dermatologist from Kentucky contacted our genetic
counseling group to discuss how to perform genetic testing on a patient:
– 64 y/o nurse practitioner with dysplastic nevus syndrome, a personal history of melanoma, no children
– No known family history of melanoma or pancreatic cancer
– Patient wishes to have p16 genetic testing performed on a self-pay basis
– Patient is interested in participating in available research protocols for melanoma
12
Should Clinical Genetic Testing be Offered to This Patient?
1. Yes
2. No
3. Maybe
13
Issues for Consideration● Statistically, the patient has only between a 0.2%-2.0% risk of carrying
a p16 mutation (Aitken et al, and Begg et al)
● The patient does NOT have features suggestive of elevated risk for carriage of a p16 mutation (Hansen et al. Lancet Oncology. 2004)
– Multiple primary melanomas– Two or more other family members with melanoma– Family member with pancreatic cancer
● Because she has already had melanoma, there is little chance that a positive or negative test result will alter prevention, early detection, management, or follow-up recommendations
● She expressed the desire for testing and willingness to pay
● Knowledge of status may provide psychological benefit to her because of her curiosity and professional background
● If p16-positive (unlikely), other family members could be tested and pancreatic cancer screening (if available) could be offered
● Research protocols are available to p16 mutation-tested individuals
14
≥3 melanomas in a family (any degree of relationship) 12%-41%
≥3 melanomas in an individual 5%-23%
≥3 “cancer events” in a family (any combination of melanoma and pancreatic cancer) ~68%
Candidates for p16 Testing:“Rule of Threes”
*Only 1 criteria needs to be met. Consideration should be given to age of diagnosis, UV exposure,
skin type, and ethnicity, as there may be exceptions to the “Rule of Threes.”
15
Should Clinical Genetic Testing be Offered to This Patient?
1. Yes
2. No
3. Maybe
Answer: Based on typical criteria used to evaluate a patient for genetic testing, the answer is “NO.”
However, as with all areas of medicine, there is “art” involved.
16
Case Presentation● 32 y/o woman with numerous clinically atypical nevi
● No personal history of melanoma
● Confirmed family history of invasive melanomain 2 of 6 siblings, and 2 paternal uncles.
● Her father died from metastatic pancreatic carcinoma
● She has 3 children (ages 10, 8, and 6 years)
● Two children have clinically atypical nevi
● She is NOT interested in participating in an available research protocol for familial melanoma
● She wishes to have p16 genetic testing performed
17
Should Clinical Genetic Testing be Offered to This Patient?
1. Yes
2. No
3. Maybe
18
Adapted from ASCO.
True negativeInconclusive
Answer: NoInterpreting a Negative Result Not Possible
MM
MM
MM
MM
p16 mutation
MM MM
MM
(-) p16 mutation
19
Should an Affected Member of the Family be Tested?
1. Yes
2. No
3. Maybe
20
Issues for Consideration● Statistically, the patient’s family has a greater than 50% risk of
carrying a p16 mutation
● Carriers in her family are also likely to be predisposed to pancreatic cancer
● She expressed the desire for testing
● If she is not interested in clinical research, there will be little change in management
● Knowledge of status may provide psychological benefit, especially if negative
● Knowledge of status may permit lifestyle change and rigorous adherence to prevention and early detection strategies in her children if positive
● Summary: Benefit of knowledge, little to no risk
● A family member would be tested in our institution if desired
21
p16 Test Reporting Study
● 45 members of p16 families received test results
● 19 non-carriers, 26 carriers
● 23 female, 22 male
● 43/45 reported benefits or positive aspects to testing
● 40/45 reported no downside or negative aspects
22
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
p16- NoMelanoma History
p16+ NoMelanoma History
p16+ MelanomaHistory
Baseline
1 Month
Underscreeners
1 SSE/Month (On Target)
Overscreeners
Receipt of Positive p16 Results Increases Screening
P < .0003
P < .023
n.s.
Aspinwall et al. Cancer Epidemiol Biomarkers Prev. 2008;17(6):1510-1519.
23
How Should it be Done?
● Identify high-risk patients
● Get Help First Time Around!! Refer to a research protocol Consult a clinical genetic testing center
• Find a local center: www.nsgc.org
• www.cancer.gov/ (National Cancer Institute)
• Huntsman Cancer Institute: [email protected]
24
Where is Testing Performed?
● Clinical U.S. genetic laboratories offering p16 genetic testing (some will assist with obtaining insurance approvals) Find details at www.genetests.org Current CLIA certified laboratories
• GeneDX (USA)• Myriad Genetic Laboratories (USA)• Yale University School of Medicine (USA)
25
How Much Does it Cost?
● Approximately $750 for first test
● Site-specific testing about $385
● 70% who go through pre-authorization receive 90% coverage on average
26
Conclusions for Genetic Testing● It is difficult to perform clinical genetic testing in the
average outpatient setting
● Patient selection for candidacy is crucial
● Informed consent and pre- and post-test counseling is important
● Enrollment of patients in a research protocol for hereditary melanoma is preferable whenever possible, though patients may wish to choose protocols that report results
● Special situations may arise in which clinical genetic testing is appropriate for a given individual, but should never replace the standard criteria for testing