Transcript Slide 1
Breast cancer case study
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level 8 - undergraduate students
Introduction to this resource
This case study follows the progress of a patient and her family in the genetic clinic.
Different clinical areas gather family history information using different methods. Before progressing with this case study you may want to
refresh your knowledge of family history taking . Otherwise
click the ‘Next’ button below.
Family History –Symbols and relationship lines
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You first need to know the symbols and relationship lines. Here you can find these and it would be useful to print out this document whilst you constructing the family tree.
Constructing family tree
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This animation is a step by step presentation of the details in creating a meaningful family tree.
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PowerPoint presentation of this animation is also available at ScotGEN website
The red boxes are "action boxes", and they provide suggested activities, such a discussions, reflection points and more practical activities.
The light blue boxes are "content boxes", read them carefully because all the key information can be found here.
The green boxes are "answer boxes", and they provide the answer to the previous activity.
The orange boxes are “practice boxes", they highlight areas where clinical practice varies in different settings.
Click for suggested learning outcomes
Learning outcomes
Describe the role of genes in the development of breast cancer Develop insight into the underlying basis of familial predisposition to breast cancer Examine the role of the genetic services in providing risk assessment, diagnosis, management options & genetic testing in the Scottish context
Breast cancer affects around 1 in 10 British women at some time in their lives.
Most cases of breast cancer arise by chance. However, a few women are more likely to develop breast cancer because of their genetic make up.
In this case study you will learn about how breast cancer can run in families, and what can be done to help women who have a family history of breast cancer.
Index
• • • • • • • • •
Breast Cancer case study – Part I
Referral to the Genetics Clinic
Breast Cancer case study – Part II
Breast Cancer case study – Part I Mollie Briggs has surgery for breast cancer when she is 42. She tells the staff nurse looking after her that her mother also had breast cancer in her 40s. She is worried about the risks to her two teenage daughters and her sister Wendy Adams.
Action box
(Prior knowledge of drawing a family tree is required for this activity) Different genetic clinics use different methods to gather family history information. The process of drawing a family tree is the same however the information is gathered. See section 2 for more information.
Open the completed family history form from Wendy Adam Now draw the family tree (pedigree) from the form. It is important you do this to complete the case study You may need a reminder of pedigree symbols and relationship lines This activity should take about half an hour.
Answer box
Below you will find a computer drawn family tree from Wendy’s completed family history form.
Open the correct drawing document to see what your family tree should look like. Compare the correct drawing document with the family tree you have drawn yourself and correct any errors you have made. Keep this family tree for use in later activities.
Although your family tree will be hand drawn, and you may have a different key to represent the different types of cancers, the structure of the family tree should look the same.
Referral to the Genetics Clinic The staff nurse advises Mollie to tell her sister to ask for a referral to the local genetics clinic.
Mollie and her sister attend the genetic clinic together. A genetic counsellor draws the family tree like you have done. With written consent, s/he confirms that their mum had breast cancer using the Scottish cancer registry .
It is good practice in a genetic department to confirm the primary diagnosis of cancer from clinical records for relevant affected relatives.
Practice point
Read the following information about confirmation of cancer.
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Why should we confirm cancers?
Some people share the wrong information with their family.
• Confirm the aetiology of specific cancers.
Confirm age at diagnosis.
Note:
If a person with cancer is alive and their cancer is required to be confirmed, a signed consent form must be sent to cancer registry with the request. Click here to see one sample form. (each service will have their own consent forms)
Sources used to confirm a cancer diagnosis.
Hospital notes or electronic file, GP notes, cancer registry, births, marriages & deaths and occasionally from patient held notes or letters.
Different genetic services use these different options to different degrees depending upon availability.
You could discuss as a group, any difficulties you may experience with getting information to confirm cancers.
The genetic counsellor explains the causes of breast cancer.
Action box
Mutations in one or more genes in a cell can cause cancer. A person can inherit a mutation (gene change) from his/her parents or acquire it during his/her lifetime. A somatic (acquired) mutation can be caused by environmental factors, such a cigarette smoke, radiation, alcohol.
The genetic counsellor explains the causes of breast cancer.
Action box
Mutations in one or more genes in a cell can cause cancer. A person can inherit a mutation (gene change) from his/her parents or acquire it during his/her lifetime. A somatic (acquired) mutation can be caused by environmental factors, such a cigarette smoke, radiation, alcohol.
Sporadic breast cancer
No mutation inherited at birth Other unknown factors Radiation Dietary and hormonal factors
Familial breast cancer
Mutation inherited at birth
Breast cancer
Practice point
Genetic counsellors use evidence based guidelines to estimate risk and recommend management for patients with familiar breast cancer.
There are local variations in the guidelines.
In Scotland, agreed guidelines were the subject of a recent health department letter (HDL). They can be viewed here .
In England and Wales the NICE guidelines are used.
Risk of breast cancer The counsellor explains that in Mollie’s case the cancer is unlikely to be caused by mutations in the high risk genes BRCA1 or BRCA2, but that Wendy does have a moderate risk of developing breast cancer. Her risk is more than twice that of the general population.
Practice point
Look at the following links for information about: Screening Genetic counselling: from Macmillan website Heredity: from Macmillan website and Nursingtimes website and Nursingtimes website
Mammography Mammography is the key screening strategy in the moderate risk group.
The evidence can be found within the NICE guidelines .
Action box
Click here for more information about mammography.
Action box
With the family history you have constructed, use your local breast cancer genetics guidelines to determine what surveillance and screening Mollie’ daughters will be offered and from what age.
Answer box
According to both the Scottish and NICE guidelines, Wendy should be offered annual mammography from her present age until 50.
Note for educators
First part of the learning object finishes here.
The following part can be used to follow part one for a more in depth exercise.
Breast Cancer case study – part 2 Four years later Wendy’s aunt Catherine Smart is diagnosed with ovarian cancer and she learns that her mother’s paternal aunt also had breast cancer.
Action box
Add this new information to your pedigree.
Use your local guidelines to reassess Wendy’s risk .
Answer box
Open the correct drawing document to see what your family tree should look like now.
The new family history information changes Wendy’s risk to high based on Scottish and NICE guidelines.
Genetic testing – Part I The genetic counsellor tells Wendy that genetic testing would now be available for her family. The counsellor explains that with Mollie’s informed consent her sample can be tested and that the result could have implications for other relatives.
Practice point
Genetic testing always requires a DNA sample from an affected relative. The testing and interpretation of results is complex and can take several months.
Go to the Macmillan website for more information about genetic testing .
Mollie consents to give a sample for testing of the BRCA1 and 2 genes. The test shows she has a mutation (also may be described as a gene change) in the BRCA2 gene.
Click here to see Mollie’s results
Action box
What is Wendy’s risk of breast cancer now?
Is she at risk of any other type of cancer?
Answer box
Mum Dad Working copy of BRCA gene Faulty copy of BRCA gene Children Wendy has a 50% or 1:2 chance of inheriting the faulty gene.
BRCA1 risk of Breast cancer ~80%; Ovarian cancer ~65% BRCA2 risk of Breast cancer ~88% and Ovarian ~37% Ref: Evans DG et al. (2008). in a Clinical cancer Genetics Service setting: risk of breast/ovarian cancer quoted should reflect the cancer burden in the family.
Penetrance estimates for BRCA1 and BRCA2 based on genetic testing BMC Cancer 8:155 [ Electronic version ]
Answer box
Mum Dad Working copy of BRCA gene Faulty copy of BRCA gene Children chance of developing breast and ovarian cancer.
Women who inherit a faulty BRCA1 or BRCA2 gene will have a very high Men who inherit a faulty gene have an increased risk of developing prostate cancer and can pass the gene on to their children.
Men with BRCA2 gene changes have an increased risk of developing breast cancer themselves.
Genetic testing – Part II Wendy is offered a blood test to see if she has inherited the gene change. She is sent away to think about it and comes back to have the test a month later. She decides to take the test.
Action box
Click below to view Wendy’s result.
Click here to see Wendy’s results
Wendy is very pleased that she and her children are now at population risk of breast and ovarian cancer. Neither she nor they need to consider prophylactic surgery or have additional screening outwith the National Breast Screening Programme (NBSP).
Action box options for educator- discussion What is the risk to her children now?
What if Wendy’s test had shown a mutation?
Practice point
Read about DNA analysis of the BRCA1 and BRCA2 genes .
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What is the risk to her children now?
Answer box
Their risk is similar to that of the general population.
What if test result was positive?
Wendy would be at a very high risk of breast and ovarian cancer • 1:2 (50%) risk of passing the faulty gene to her children.
• Wendy would have additional options of MRI or prophylactic mastectomy. • Prophylactic bilateral salpingo-oopherectomy.
Congratulations!
You completed this case study.
Further reading