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© The Canadian Journal of Urology™; 23(2); April 2016
information to help determine if testing is right for them
and the family, and to streamline the testing process.
Agenetic counselor is a healthcare professional with
specialized training inmedical genetics and counseling
for genetic testing. The genetic counselor is central to
the process of genetic evaluation to inform patients
about the benefits and limitations of genetic testing,
implications of cancer risks for patients and their
families, and further management based upon existing
practice guidelines. Genetic counselors also coordinate
genetic testing with commercial laboratories andmeet
with patients after test results are available (disclosure
visit) to interpret test findings and place findings in
the context of the individual’s family cancer history.
Therefore, referral to genetic counseling is crucial for
prostate cancer genetic testing to address cancer risk
implications for the patient and their family. Table 1
highlights the cancer risks associated with mutations
in the genes implicated in prostate cancer inheritance.
As can be seen in Table 1, a mutation in a given gene
can predispose the proband to the cancer in question
(in this case prostate cancer) but may also predispose
to additional cancers which were unanticipated by
the patient. Depending on the cancers, heightened
screening or additional screening may be needed
that were not expected for the patient presenting for
genetic testing. Furthermore, genetic test results may
be inconclusive. Anegative genetic test result may not
necessarily rule out a familial mutation if there was not
a mutation identified in the family. Without a positive
test in a family member, the negative result in the
proband (individual presenting for genetic counseling)
would be interpreted as indeterminate or inconclusive.
An additional finding that can be reported to the
patient is variant of uncertain significance (VUS).
These variants do not meet all laboratory criteria to be
classified as pathogenic or benign, and are reported to
patients as uncertain significance. These variants are
typically followed to gather more evidence andmay be
reclassified to pathogenic or polymorphism. However,
VUSs can cause patients anxiety or be misinterpreted
by clinicians and patients as a mutation, leading to
unnecessary recommendations for cancer screening
or risk reductionmeasures. Therefore, an experienced
genetic counselor or genetics professional is crucial to
educate and assist patients about potential test results
and implications for the patient and their family to
make an informed decision about genetic testing for
inherited cancer risk assessment.
Method
Institutional priority to address field challenges
Advancing the field of genetic testing for prostate
cancer has become a commitment at our institution.
As such, a genitourinary (GU) genetics clinic was
started with a dedicated focus in evaluating patients
with or at-risk for GU cancers for inherited cancer
predisposition with formal genetic counseling and
genetic testing. For maximal point of contact with
patients and urologic providers, our institution has
implemented the GU genetics clinic alongside of
the existing GU Multidisciplinary clinic – a dynamic
multispecialty clinic where patients with prostate
cancer can have consultations fromurologic oncology,
radiation oncology, and medical oncology regarding
their prostate cancer management.
12
Appropriate
patients presenting to the multidisciplinary clinic are
offered an opportunity to undergo genetic consultation
to round out their assessment.
8250
How I Do It: Genetic counseling and genetic testing for inherited prostate cancer
TABLE 1.
Spectrum of cancer risks for genes associated with prostate cancer predisposition
Prostate Breast Ovarian Pancreatic Melanoma Colon Gastric/ Uterine Sebaceous
small
carcinoma
bowel
BRCA1
x
x
x
x
x
and
BRCA2
DNA
x
x
x
x
x
x
mismatch
repair genes*
HOXB13
x
*Studies describe higher rates of prostate cancer in Lynch syndrome families. Emerging data implicate DNAmismatch repair
genes in prostate cancer predisposition, though definitive studies are warranted.