Genetic Testing for Breast and Ovarian Cancer Susceptibility: A Family Experience

Marcia Van Riper, RN, PhD

J Midwifery Womens Health. 2004;49(3)

Abstract and Introduction

The purpose of this article is to provide an overview of current knowledge concerning genetic testing for breast and ovarian cancer susceptibility. This overview includes 1) a brief history of genetic testing for breast and ovarian cancer susceptibility, 2) a review of factors that midwives and other health care providers need to consider before offering this type of testing to their clients, 3) management options for clients at high risk for hereditary breast and ovarian cancers, and 4) a discussion of preliminary findings from an ongoing study concerning the family experience of genetic testing, which illustrates some of the ethical issues that emerge for individuals and families during the family experience of genetic testing for breast and ovarian cancer susceptibility.

Significant advances have been made in understanding the genetic components of breast and ovarian cancer.^[1] Genes associated with an increased risk of these cancers, such as Breast Cancer 1 (BRCA1) and Breast Cancer 2 (BRCA2), have been cloned, and genetic tests for mutations in these genes have been available for almost a decade. The availability of genetic testing for breast and ovarian cancer susceptibility affords unprecedented opportunities for individuals and families to learn whether they have an increased risk for developing these potentially fatal conditions. Even more importantly for some individuals, the availability of genetic testing gives them a chance to find out if they have the potential to transmit genetic mutations to their offspring.^[2] Awareness of genetic risk can also facilitate informed health care decisions and, in some cases, can promote risk reduction behaviors that have the potential to reduce morbidity and mortality.^[3]

Although the increased availability of genetic testing for breast and ovarian cancer susceptibility has the potential to make important contributions to the health and well-being of individuals and families at increased risk for these cancers, it also has the potential to create moral quandaries for these same individuals and their families.^{[4,5,6,7,8,9]} According to Thomson,^[10] the major risk associated with genetic testing is that of gaining information: information that may result in increased anxiety, altered family relationships, discrimination, or stigmatization; information that may be difficult to keep confidential; and information about which little can be done, in most cases.

Currently, many health care providers lack the knowledge base necessary to help individuals and families make informed decisions about genetic testing for breast and ovarian cancer susceptibility. This is due, in part, to the fact that many health care providers have had little, or no, formal education in genetics.^[11,12,13] In addition, advances in genetics have been occurring so rapidly, some health care providers may find it difficult to keep abreast with new discoveries. Finally, for some health care providers, especially primary care providers, the relevance of genetics may not be obvious^[14] and because of this, they may have minimal interest in becoming better educated about genetics.^[12]

The purpose of this article is to provide an overview of current knowledge concerning genetic testing for breast and ovarian cancer susceptibility. This overview includes 1) a brief history of genetic testing for breast and ovarian cancer susceptibility, 2) a review of factors that midwives and other health care providers need to consider before offering this type of testing to their clients, 3) management options for clients at high risk for hereditary breast and ovarian cancers, and 4) a discussion of preliminary findings from an ongoing study concerning the family experience of genetic testing, which illustrates some of the ethical issues that emerge for individuals and families during the experience of genetic testing for breast and ovarian cancer susceptibility.

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Table 1. Risk of Developing Cancer in Persons With BRCA1 and BRCA2 Mutations

Type of Cancer

General Population

BRCA1 Mutation

BRCA2 Mutation

Breast (female)

By 70 years of age (%)

56-87^{[24,36,37,39]}

45-71^[36,37,40]

2nd breast cancer

Based on family history

By 70 years of age (%)

64^[38]

50^[40]

Within 5 years of 1st breast cancer (%)

20^[39]

12^[41]

Breast (male) (%)

? increased risk

6^[40]

Ovarian (%)

1.5

39-60^[23,36]

11-27^[23,36]

Prostate

3-fold increased risk^[23]

3-7-fold increased risk^[40]

Table 2. Two Models for Estimating Lifetime Risk of a Women Developing Breast Cancer
Model	Factors Considered	Advantages	Limitations
Gail model https://www.nci.nih.gov	Current age Age at menarche Age at 1st live birth Number and outcome of previous breast biopsies Presence of atypical hyperplasia Number of 1st-degree relatives with breast cancer	Validated as a predictor of breast cancer in women who undergo regular mammography screening	Overestimates risk in women who do not get screening regularly Less accurate in predicting hereditary breast and ovarian cancer because it fails to take into account paternal transmission of cancer mutations, 2nd-degree relatives, age at diagnosis, ethnicity, and other types of cancer
Claus model	Current age Number of 1st- and 2nd-degree relatives with breast cancer Age of cancer onset	Most effective in evaluating the lifetime risk of breast cancer in families in which only one or two family members have cancer	Maximum number of affected family members the model can accommodate is two Underestimates risk when there is a high likelihood of a BRCA mutation because it does not consider ovarian cancer and paternal transmission

Table 2. Two Models for Estimating Lifetime Risk of a Women Developing Breast Cancer
Model	Factors Considered	Advantages	Limitations
Gail model https://www.nci.nih.gov	Current age Age at menarche Age at 1st live birth Number and outcome of previous breast biopsies Presence of atypical hyperplasia Number of 1st-degree relatives with breast cancer	Validated as a predictor of breast cancer in women who undergo regular mammography screening	Overestimates risk in women who do not get screening regularly Less accurate in predicting hereditary breast and ovarian cancer because it fails to take into account paternal transmission of cancer mutations, 2nd-degree relatives, age at diagnosis, ethnicity, and other types of cancer
Claus model	Current age Number of 1st- and 2nd-degree relatives with breast cancer Age of cancer onset	Most effective in evaluating the lifetime risk of breast cancer in families in which only one or two family members have cancer	Maximum number of affected family members the model can accommodate is two Underestimates risk when there is a high likelihood of a BRCA mutation because it does not consider ovarian cancer and paternal transmission

Table 3. Two Models Available for Estimating the Likelihood of Finding a BRCA Mutation
Model	Factors Considered	Use by Health Care Providers
Myriad model	Age at breast cancer diagnosis Family history information Presence of ovarian cancer in the family Ethnicity	Health care providers can use a table of mutation prevalence data, available on the Myriad Web site (https://www.myriad.com/gtmp.html), to estimate the likelihood of their client being a carrier of a BRCA mutation.
BRCAPRO	Age at breast cancer diagnosis 1st- and 2nd-degree family history Presence of male and female breast cancer Presence of ovarian cancer Ethnicity Size of family	Health care providers can estimate the likelihood of their client carrying a BRCA1 or BRCA2 mutation by using this computer program, which is based on data from published studies of prevalence, penetrance, and mutation frequency. Further information about this model can be found at https://www.astor.som.jhmi.edu/brcapro/.

Table 4. Features Suggestive of Hereditary Breast/Ovarian Cancer
Diagnosis of breast cancer before age 50 Bilateral breast cancer Breast and ovarian cancer in the same individual Personal or family history of male breast cancer Ashkenazi Jewish ancestry in association with a personal and/or family history of breast and/or ovarian cancer Multiple cases of early-onset breast cancer ( Autosomal dominant pattern of inheritance Presence of other cancers associated with mutations in BRCA genes (i.e., prostate, pancreatic, gallbladder/bile duct, melanoma)

Table 5. Management Options for Individuals at Increased Risk for Hereditary Breast and Ovarian Cancer
Management Options	Breast Cancer	Ovarian Cancer
Increased surveillance	Self-breast examination Clinical breast examination Mammography Ultrasound MRI	Pelvic examination CA-125 Transvaginal ultrasound
Chemoprevention	Tamoxifen	Oral contraceptives
Prophylactic surgery	Prophylactic mastectomy Prophylactic oophorectomy	Prophylactic oophorectomy

Appendix A. Breast and Ovarian Cancer Counseling Resources for Health Care Providers
Resource	Description
Cancer Facts Genetics of Breast and Ovarian Cancer https://www.nci.nih.gov/cancerinfo/pdq/genetics/breast-and-ovarian#Section_2	Accurate, up-to-date information on the genetics of breast and ovarian cancer provided by the National Cancer Institute
Cancer Genetics Services Directory https://www.nci.nih.gov/search/geneticservices/	Directory of health care providers who provide services related to cancer genetics
Resource Link--National Society of Genetic Counselors https://www.nsgc.org/resourcelink.asp	Provides links to Genetics Resources
International Society of Nurses in Genetic https://www.globalreferrals.com/isong.html	Provides valuable links to a number of nursing and genetic sites, as well as links to family support organizations
Oncology Nursing Society https://www.ons.org/xp6/ONS/Login/Splash.xml	An information service for oncology nurses, other health care providers, people with cancer, and their family and friends
Breast Cancer Genetics Network of Michigan https://www.mi-cancergenetics.org/index.html	Network designed to help breast cancer patients and their families make informed decisions and become active partners in their health care
Facing Our Risk of Cancer Empowered (FORCE) https://www.facingourrisk.org/	Nonprofit organization for women who are at high risk for getting breast cancer due to their family history and genetic status

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Genetic Testing for Breast and Ovarian Cancer Susceptibility: A Family Experience

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