Chapter 31 genetic counselling

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

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.”

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

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).

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.

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.

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.

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

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?

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.

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.

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.

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.

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.

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%.

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

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.

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.

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.

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.

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.

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.

COUNSELING SESSION
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.

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.

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.

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)
inhibitors in combination with chemotherapy.

COUNSELING SESSION
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.

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

Chapter 31 genetic counselling

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