Genetic Counselling Guide

GENETIC
COUNSELLING
DR. AADITYA PRAKASH
DNB RT , RESIDENT
BMCHRC , JAIPUR

– Cancer genetic counselling is a communication process
between a health-care professional and an individual
concerning cancer occurrence and risk in his or her family.
MAIN ELEMENTS
1. Diagnostic and clinical aspects
2. Documentation of family and pedigree information
3. Recognition of inheritance patterns and risk estimation
4. Communication and empathy with those seen
5. Information on available options and further measures
6. Support in decision-making and for decisions made
WHAT IS GENETIC COUNSELING?

WHO IS A CANDIDATE FOR CANCER
GENETIC COUNSELING?

NCCN CRITERIA FOR BREAST
CANCER RISK ASSESSMENT

NCCN CRITERIA FOR
GASTROINTESTINAL CANCER
RISK ASSESSMENT

COMPONENTS OF THE CANCER
GENETIC
COUNSELING SESSION
Precounseling Information / Contracting :
– Contracting is the term used to describe the
beginning of the encounter when the counselor
and counselee share their intentions for the
session.
– Counselee should be informed about:-
• what to expect at each visit
• what information he/she should collect ahead of
time

GENETIC
COUNSELING SESSION
Precounseling Information / Contracting :
– “Doorknob syndrome” is common and results
when patients are not given the opportunity to
share their thoughts and concerns with providers
and choose to do so only near the end of the
session.
– Contracting may actually shorten the length of a
genetic counseling session, as it can potentially
prevent the “doorknob syndrome”.

INFORMED CONSENT
– “The process of obtaining a patient's permission
for a procedure after the patient and doctor have
discussed the risks, benefits, and alternatives of
the procedure and the patient understands them.”

GENETIC
COUNSELING SESSION
Obtaining the Family History:
– Family history should include at least three
generations
– Important to gather information on both maternal
and paternal lineages
– Particular focus on individuals with malignancies
(affected) and noncancer phenotypes associated
with inherited cancer predisposition syndromes

GENETIC
COUNSELING SESSION
Information on All Individuals:
• Important to document each individual’s age or
age at death as well as his/her personal history of
cancer or benign tumors.
• Important to include the presence of nonmalignant
findings in the proband and family members, as
some inherited cancer syndromes have other
physical characteristics associated with them (e.g.,
trichilimommas with Cowden Syndrome).

GENETIC
COUNSELING SESSION
Information on All Individuals:
– General medical information can also be pertinent
to the patient’s future medical management.
– Lifestyle factors can influence hereditary cancer
risk, such as smoking.

GENETIC
COUNSELING SESSION
Information on Affected Individuals:
– For individual affected with cancer:-
• Important to document the exact diagnosis, age at
diagnosis, treatment strategies, and environmental
exposures(i.e., occupational exposures, cigarettes,
other agents).
– The current age of the individual, laterality, and
occurrence of any other cancers must also be
documented.
– Cancer diagnoses should be confirmed with
pathology report.

GENETIC
COUNSELING SESSION
Information on Affected Individuals:
– Details about the pathology of the tumor can be
very helpful.
E,g:-
Invasive ductal breast cancers that are ER, PR, and
HER2 negative on pathology (“triple negative” or
“basaloid type”) are typically can be associated with
BRCA1 mutations while lobular breast cancer can
be associated with CDH1 mutations.

GENETIC
COUNSELING SESSION
Accuracy of Information:
CHALLENGES-
– Individual’s knowledge of the family history
– Information provided can be incorrect
– Unsure of the details surrounding that diagnosis
– Family histories can change over time

GENETIC
COUNSELING SESSION
Risk Assessment:
– Risk assessment can be broken down into three separate
components-
• What is the chance that the counselee will develop the cancer
observed in his/her family (or a genetically related cancer such
as ovarian cancer due to a family history of breast cancer)?
• What is the chance that the cancers in this family are caused by
a single gene mutation?
• What is the chance that we can identify the gene mutation in
this family with our current knowledge and laboratory
techniques?

GENETIC
COUNSELING SESSION
Risk Assessment:
– Important to distinguish the difference between a
• familial pattern of cancer (due to environmental factors or
chance) &
• hereditary pattern of cancer (due to a shared genetic mutation).
– The risk of a detectable mutation will also vary based on cancer
history and the degree of relationship to an affected family
member.
– Therefore, risk assessment process should include a discussion
of which family member is the best candidate for testing.

GENETIC
COUNSELING SESSION
DNA Testing:
– DNA testing can be very expensive.
– Full sequencing and rearrangement testing of the
BRCA1/2 genes currently averages $2,500, and
full panel testing costs up to $7,000 per patient.
– DNA testing offers the important advantage of
presenting clients with actual risks instead of the
empiric risks derived from risk calculation
models.

GENETIC
COUNSELING SESSION
Ideal Testing Candidate:
– Testing should begin in an affected family member
whenever possible to maximize scientific accuracy.
– An individual who diagnosed with a component
tumor at a young age or an individual who has two
primary component tumors.
– When a family mutation is identified, unaffected
individuals should then be offered testing, as
interpretation of test results are clear in this
scenario.

GENETIC
COUNSELING SESSION
Timing of Genetic Testing:
– For most of the inherited cancer syndromes, genetic testing
takes 4–12 weeks .
– BRCA1/2 genetic test results are typically available within 14
days of blood draw.
– The information gleaned potentially affect surgical decision
making if the results are available prior to definitive surgery.
– If a woman tests positive for a deleterious mutation, for
example, she may choose mastectomy to treat her cancer and
also undergo contralateral prophylactic mastectomy to reduce
the ≤ 60% risk of developing a second breast malignancy.

GENETIC
COUNSELING SESSION
Timing of Genetic Testing:
– Genetic testing for p53 mutations can take as little
as 3 weeks.
– It is well known that p53 mutant cells are
extremely sensitive to DNA damage .
– DNA damaging agents (e.g., chemotherapy and
radiotherapy) used for treatment of a cancer in an
individual with Li-Fraumeni Syndrome (LFS)
can cause a second malignancy.

GENETIC
COUNSELING SESSION
Implication for At-Risk Family Members:
– First-degree relatives of individuals with an autosomal dominant
hereditary cancer predisposition have a 50% chance of inheriting
the cancer predisposition gene/condition.
– Important to determine which parent carries the mutation, so that
the relatives from the respective lineage can be informed of the
family mutation and can consider the option of testing.
– Possible that both parents may test negative for their child’s
mutation (“de novo” mutation ).
– The “de novo” mutation rates for certain genes are fairly high.
For e.g, the de novo mutation rate for APC can be up to ~25% ,
for p53 is estimated at ~20%.

GENETIC
COUNSELING SESSION
Implication for At-Risk Family Members:
– Individuals with an autosomal recessive cancer
predisposition are informed that their siblings are
at a 25% risk having the condition and a 50% risk
of carrying one copy of the mutation.
– Children of individuals with autosomal recessive
cancer predisposition condition are at 100% risk
of carrying one copy of a mutation.
– e.g:-MYH-Associated Polyposis (MAP)
syndrome

GENETIC
COUNSELING SESSION
Choosing the Right Test:
– Important to determine which test to order.
– Founder mutations are useful in the initial screening process for
cancer predisposition.
– E.g:-Ashkenazi Jewish descent has a family history suggestive of
HBOC, testing for the founder mutations 185delAG and 53282insC in
BRCA1 and 6174delT in BRCA2 is indicated as an initial step.
– If this testing is negative, full gene sequencing of BRCA1/2
considered.
– It is important to note that individuals who are not of Ashkenazi
Jewish descent should not be screened for the Ashkenazi founder
mutations.

GENETIC
COUNSELING SESSION
Choosing the Right Test:
– IHC testing detects whether proteins from Lynch
syndrome genes are present in the tumor.
– If IHC of MLH1, MSH2, MSH6, and PMS2 indicates
that one of these proteins is missing, it suggests that
particular gene is not functional and germline testing of
just that specific gene would be recommended.
– Important to recognize that germline (blood) genetic
testing is not always the most appropriate first step in
the genetic testing process.

GENETIC
COUNSELING SESSION
Choosing the Right Laboratory:
– Costs and payment options are important to
review with patients.
– Important to review the technologies offered at
each laboratory in order to offer the most
appropriate test to the patient.
– Turnaround time is important to consider
especially if the results are going to be used for
immediate medical management as in the case of
breast cancer.

GENETIC
COUNSELING SESSION
When Testing Is Declined:
– It is important to refer back to the family history to make
medical management recommendations for the patient.
DNA Banking:
– In certain cases, assessment of a family history reveals
an increased number of cancer cases, but the cluster of
cancers does not suggest a recognized cancer syndrome.
– When this is the case, genetic testing is likely to be
unrevealing & DNA banking may be appropriate so that
testing may be pursued at a later date.

GENETIC
COUNSELING SESSION
Disclosure of Test Results:
– Current practice is generally to offer the patient
in-person or phone disclosure and have them
decide, as this procedure leads to greater patient
satisfaction with the testing process.
– It should be clarified that the results will be
disclosed verbally (in person or over the
telephone) and then mailed to them along with a
letter interpreting their test results.

GENETIC
COUNSELING SESSION
Options for Surveillance, Risk Reduction, and
Tailored Treatment:
– Cancer risk counseling session is a forum to
provide counselees with information, support,
options, and hope.
– Mutation carriers can be offered:- earlier and
more aggressive surveillance, chemoprevention,
and/or prophylactic surgery.

GENETIC
COUNSELING SESSION
Options for Surveillance, Risk Reduction, and Tailored
Treatment:
Options for BRCA carriers:-
– annual mammograms beginning at age 25 years,
– clinical breast exam by a breast specialist,
– Yearly breast magnetic resonance imaging (MRI) with a
clinical breast exam by a breast specialist,
– Yearly clinical breast exam by a gynecologist.
The mammogram and MRI be spaced out around the calendar
year so that some intervention is planned every 6 months.

GENETIC
COUNSELING SESSION
– Recent data suggest that MRI may be safer and more
effective in BRCA carriers <40 years of age and may
someday replace mammograms in this population.
– BRCA carriers may take a selective estrogen-receptor
modulator (SERM) or aromatase inhibitor in hopes of
reducing their risks of developing breast cancer.
– Prophylactic bilateral mastectomy reduces the risk of
breast cancer by >90% in women at high-risk for the
disease.

GENETIC
COUNSELING SESSION
– Women who carry BRCA1/2 mutations are also at increased risk to
develop ovarian, fallopian tube, and primary peritoneal cancer, even if no
one in their family has developed these cancers.
– Surveillance for ovarian cancer includes transvaginal ultrasounds and CA-
125 testing.
– Oral contraceptives reduce the risk of ovarian cancer in all women,
including BRCA carriers.
– Prophylactic bilateral salpingo-oophorectomy (BSO) is currently the most
effective means to reduce the risk of ovarian cancer and is recommended
to BRCA1/2 carriers by the age of 35 to 40 or when childbearing is
complete.

GENETIC
COUNSELING SESSION
– Reason for female BRCA carriers to consider prophylactic
oophorectomy is that it also significantly reduces the risk of a
subsequent breast cancer, particularly if they have this surgery
before menopause.
– The reduction in breast cancer risk remains even if a healthy
premenopausal carrier elects to take low-dose hormone-
replacement therapy (HRT) after this surgery.
– Early data revealed that breast and ovarian cancers in BRCA
carriers were particularly sensitive to treatment with poly
adenosine diphosphate (ADP)-ribose polymerases (PARP)

GENETIC
COUNSELING SESSION
Options for Surveillance, Risk Reduction, and Tailored
Treatment:
– Genetic counseling and testing is also available for
dozens of cancer syndromes, including Lynch syndrome,
von Hippel-Lindau syndrome, multiple endocrine
neoplasias, and familial adenomatous polyposis.
– Surveillance and risk reduction for patients who are
known mutation carriers for such conditions may
decrease the associated morbidity and mortality of these
syndromes.

GENETIC
COUNSELING SESSION
Follow-up:
– Follow-up letter to the patient is a concrete means of
documenting the information conveyed in the sessions so that
the patient and his/her family members can review it over
time.
– A follow-up phone call and/or counseling session may also
be helpful, particularly in the case of a positive test result.
– Provide patients with an annual or biannual newsletter
updating them on new information in the field of cancer
genetics or patient support groups.

ISSUES IN CANCER GENETIC
COUNSELING
Psychosocial Issues:
– Counseling session may be quite difficult for some
individuals with a family history who are not only
frightened about their own cancer risk, but also are
reliving painful experiences associated with the cancer
of their loved ones.
– Counselees may be faced with an onslaught of
emotions, including anger, fear of developing cancer,
fear of disfigurement and dying, grief, lack of control,
negative body image, and a sense of isolation.

COUNSELING
Psychosocial Issues:
– Counseling session is an opportunity for individuals to
express why they believe they have developed cancer, or
why their family members have cancer.
– By doing this , counselor will allow the clients to alleviate
their greatest fears and to give more credibility to the
medical theory.
– Preliminary data have revealed that individuals in families
with known mutations who seek testing seem to fare better
psychologically at 6 months than those who avoid testing.

COUNSELING
Presymptomatic Testing in Children:
– DNA-based diagnosis of children and young adults at
risk for hereditary medullary thyroid carcinoma
(MTC) is appropriate and has improved the
management of these patients.
– DNA-based testing for MTC is virtually 100%
accurate and allows at-risk family members to make
informed decisions about prophylactic thyroidectomy.
– FAP is a disorder that occurs in childhood and in
which mortality can be reduced if detection is
presymptomatic.

COUNSELING
Presymptomatic Testing in Children:
– “Whenever childhood testing is not medically
indicated, it is preferable that testing decisions
are postponed until the children are adults and
can decide for themselves whether to be tested.”
– The risks of such testing to the child, and the
child’s right not to be tested must be considered.

COUNSELING
Confidentiality:
– The level of confidentiality surrounding cancer genetic
testing is paramount due to concerns of genetic
discrimination.
– Careful consideration should be given to the confidentially
of family history information, pedigrees, genetic test results,
pathology reports, and the carrier status of other family
members as most hospitals and clinicians transition to
electronic medical records systems.
– Confidentiality of test results within a family can also be of
issue, because genetic counseling and testing often reveals
the risk statuses of family members other than the patient.

COUNSELING
Confidentiality:
– Many programs have built in a “share information
with family members” clause to their informed
consent documents.
– More recent recommendations state that
confidentiality should be violated if the potential
harm of not notifying other family members
outweighs the harm of breaking a confidence to
the patient.

COUNSELING
Insurance and Discrimination Issues:
– The fear of health insurance discrimination by
both patients and providers is one of the most
common concerns.
– Health-care providers should confidently reassure
their patients that genetic counseling and testing
will not put them at risk of losing group or
individual health insurance.

COUNSELING
Reproductive Issues:
– Reproductive technology in the form of
preimplantation genetic diagnosis, prenatal
testing, or sperm sorting are options for men and
women with a hereditary cancer syndrome.
– If a BRCA2 carrier is considering having a child,
it is important to assess the spouse’s risk of also
carrying a BRCA2 mutation.

SYMBOLS USED IN
DRAWING A PEDIGREE

Genetic Counselling Guide

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Genetic Counselling Guide

Similar to Genetic Counselling Guide (20)

Recently uploaded

Recently uploaded (20)

Genetic Counselling Guide