Hereditary syndromes that increase the risk of breast cancer are not common, but it is critical to recognize and manage them appropriately. This paper reviews the management of patients with the most common hereditary breast cancer syndromes, ie, hereditary breast and ovarian cancer syndrome, hereditary diffuse gastric cancer, Cowden syndrome (PTEN hamartoma tumor syndrome), Peutz-Jeghers syndrome, and Li-Fraumeni syndrome.

• In addition to breast cancer, hereditary cancer syndromes increase the risk of other malignancies, with the patterns of malignancy varying by causative genetic mutation.
• Genetic counselors, medical breast specialists, surgical breast specialists, gynecologic oncologists, and others can help, but the primary care provider is the nucleus of the multidisciplinary team.
• Management of these patients often includes surveillance, chemoprevention, and prophylactic surgery.
• All decisions about surveillance, chemoprevention, and surgical risk reduction should be shared with the patient.

While most cases of breast cancer are sporadic (ie, not inherited), up to 10% are attributable to single-gene hereditary cancer syndromes.1–4 People with these syndromes have a lifetime risk of breast cancer much higher than in the general population, and the cancers often occur at a much earlier age.
With genetic testing becoming more common, primary care physicians need to be familiar with the known syndromes, associated risks, and evidence-based recommendations for management. Here, we review the management of cancer risk in the most common hereditary breast cancer syndromes, ie:

• Hereditary breast and ovarian cancer syndrome5
• Hereditary diffuse gastric cancer
• Cowden syndrome (PTEN hamartoma tumor syndrome)
• Peutz-Jeghers syndrome
• Li-Fraumeni syndrome.

While most cases of breast cancer are sporadic, up to 10 percent are attributable to single-gene hereditary cancer syndromes. People with these syndromes have a lifetime risk of breast cancer much higher than in the general population, and the cancers often occur at a much earlier age.
With genetic testing becoming more common, primary care physicians need to be familiar with the known syndromes, associated risks and evidence-based recommendations for management.
Primary care physicians are central
Women who have a hereditary predisposition to breast cancer face complex and emotional decisions about the best ways to manage and reduce their risks. Their management includes close clinical surveillance, chemoprevention and surgical risk reduction.
Referral to multiple subspecialists is an important component of these patients’ preventive care. They may need referrals to a cancer genetic counselor, a high-risk breast clinic, a gynecologic oncologist and counseling services. They may also require referrals to gastroenterologists, colorectal surgeons, endocrinologists and endocrine surgeons, depending on the syndrome identified.
Screening and management guidelines for hereditary breast cancer syndromes are evolving. While subspecialists may be involved in enhanced surveillance and preventive care, the primary care physician is the central player, with both a broader perspective and knowledge of the patient’s competing medical issues, risks and preferences.
In addition to breast cancer, the risk of other malignancies is also higher, with the pattern varying by syndrome. Primary care physicians need to be familiar with these risks to provide adequate referrals.
Who is at increased risk of breast cancer?
Even without a hereditary cancer syndrome, a combination of reproductive, environmental, personal and family history factors can confer a 20 percent lifetime risk. But for women with hereditary syndromes, the risk far exceeds 20 percent regardless of such risk factors.
In general, referral for genetic counseling should be considered for patients and their families who have:

• Early-onset breast cancers (before age 50)
• Bilateral breast cancers at any age
• Ovarian cancers at any age
• “Triple-negative” breast cancers
• Male breast cancer at any age
• Cancers affecting multiple individuals and in multiple generations
• Breast, ovarian, pancreatic or prostate cancer in families with Ashkenazi Jewish ancestry

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