Clinical Review

Who needs breast cancer genetics testing?

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Identifying patients who are appropriate candidates for breast cancer genetics testing is a key step toward prevention and value-based care

Take-home points

  • The best genetics test is a good family history, updated annually
  • Each year, 35,000 breast cancers are attributable to hereditary risk
  • It is crucial to identify families at risk for hereditary breast cancer early, as cancers may begin in a woman's 30s; screening begins at age 25
  • Multigene panel testing is efficient and cost-effective
  • For patients who have highly penetrant pathogenic variants and are of childbearing age, preimplantation genetics diagnosis is an option


 

References

Illustration: Kimberly Martens for OBG Management
ObGyns counsel many women with a personal or family history of breast cancer. Many of these patients can benefit from genetics counseling and testing. This particular patient has a family history of breast cancer and metastatic prostate cancer on her maternal side, which raises a “red flag” for hereditary cancer syndrome.

Advances in cancer genetics are rapidly changing how clinicians assess an individual’s risk for breast cancer. ObGyns counsel many women with a personal or family history of the disease, many of whom can benefit from genetics counseling and testing. As patients with a hereditary predisposition to breast cancer are at higher risk and are younger at diagnosis, it is imperative to identify them early so they can benefit from enhanced surveillance, chemoprevention, and discussions regarding risk-reducing surgeries. ObGyns are uniquely poised to identify young women at risk for hereditary cancer syndromes, and they play a crucial role in screening and prevention over the life span.

CASE Patient with breast cancer history asks about screening for her daughters

A 52-year-old woman presents for her annual examination. She underwent breast cancer treatment 10 years earlier and has done well since then. When asked about family history of breast cancer and ethnicity, she reports her mother had breast cancer later in life, and her mother’s father was of Ashkenazi Jewish ancestry.In addition, a maternal uncle had metastatic prostate cancer. You recall that breast cancer diagnosed before age 50 years and Ashkenazi ancestry are “red flags” for a hereditary cancer syndrome. The patient wonders how her daughters should be screened. What do you do next?

Having a risk assessment plan is crucial

Given increasing demands, limited time, and the abundance of information to be discussed with patients, primary care physicians may find it challenging to assess breast cancer risk, consider genetics testing for appropriate individuals, and counsel patients about risk management options. The process has become even more complex since the expansion in genetics knowledge and the advent of multigene panel testing. Not only is risk assessment crucial for this woman and her daughters, and for other patients, but a delay in diagnosing and treating breast cancer in patients with hereditary and familial cancer risks may represent a worrisome new trend in medical litigation.1,2 Clinicians must have a process in place for assessing risk in all patients and treating them appropriately.

The American Cancer Society (ACS) estimated that 252,710 cases of breast cancer would be diagnosed in 2017, leading to 40,610 deaths.3 Twelve percent to 14% of breast cancers are thought to be related to hereditary cancer predisposition syndromes.4–8 This means that, every year, almost 35,000 cases of breast cancer are attributable to hereditary risk. These cases can be detected early with enhanced surveillance, which carries the highest chance for cure, or prevented with risk-reducing surgery in identified genetic mutation carriers. Each child of a person with a genetic mutation predisposing to breast cancer has a 50% chance of inheriting the mutation and having a very high risk of cancer.

In this patient’s case, basic information is collected about her cancer-related personal and family history.

Asking a few key questions can help in stratifying risk:

  • Have you or anyone in your family had cancer? What type, and at what age?
  • If breast cancer, did it involve both breasts, or was it triple-negative?
  • Is there a family history of ovarian cancer?
  • Is there a family history of male breast cancer?
  • Is there a family history of metastatic prostate cancer?
  • Are you of Ashkenazi Jewish ethnicity?
  • Have you or anyone in your family ever had genetics testing for cancer?

The hallmarks of hereditary cancer are multiple cancers in an individual or family; young age at diagnosis; and ovarian, pancreatic, or another rare cancer. Metastatic prostate cancer was added as a red flag for hereditary risk after a recent large series found that 11.8% of men with metastatic prostate cancer harbor germline mutations.9

CASE Continued

On further questioning, the patient reports she had triple-negative (estrogen receptor–, progesterone receptor–, and human epidermal growth factor receptor 2 [HER2]–negative) breast cancer, a feature of patients with germline BRCA1 (breast cancer susceptibility gene 1) mutations.10 In addition, her Ashkenazi ancestry is concerning, as there is a 1-in-40 chance of carrying 1 of the 3 Ashkenazi founder BRCA mutations.11 Is a genetics consultation needed?

Read about guidelines for referral and testing.

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