Most breast cancer is not clearly hereditary. This is often called “sporadic cancer.” In some families, we see more of the same or related kinds of cancer than we would expect to see by chance alone. Some of this can be explained by a hereditary cause while others fall into what is known as “familial cancer” where there does not appear to be a specific pattern of inheritance but the family history is still concerning. Over 10% of breast cancers are caused by an inherited genetic mutation.

Why is this important? The cancer risks associated with hereditary breast cancer is much higher than those with familial or general population breast cancers (see graph).

The only way to truly differentiate between familial and hereditary cancer risks and thereby providing the most appropriate medical management to patients is by utilizing hereditary cancer testing, as seen in the case study below.

myRisk - CS4_IMG1_V2

Patient Clinical Profile

  • Patient Age: 35
  • Gender: Female
  • Cancer: Unaffected
  • Pregnancy: G2P2
  • Contraceptive: None
  • Tested: Multi-gene panel in June 2016
  • Visit Type: Contraceptive Consult (Patient Desires IUD)
  • Visit notes: This patient’s Ob-Gyn followed ACOG’s recommendations4 and collected a full cancer family history at the beginning of her visit, prior to discussing contraceptive options. After evaluating her family history, the provider suspected a hereditary cause to the concerning breast cancer in her family and ordered Myriad myRisk® Hereditary Cancer Test to help her accurately stratify this patient’s risk for cancer.


Myriad myRisk® Panel Test Result:

Negative
No Clinically Significant Mutation Detected

Patient’s Family History

Relative Cancer Type Age of Dx
Mother Breast 47
Maternal Aunt Breast 40
Paternal Grandmother Breast 60

Breast Cancer Management Considerations

RISK TYPE MANAGEMENT
General Population Risk1,5
FEMALE:
  • Education about breast awareness and clinical breast exams every 1-3 years beginning at age 25
  • Annual clinical breast exams and screening mammography beginning at age 40
MALE (cancer risk <0.1%1 by age 70):
  • No current screening guidelines exist
Familial Risk4,5
FEMALE:
  • Consideration of annual screening mammogram + clinical breast exam every 6-12 months to begin 10 years prior to youngest family member but not less than age 30
  • Consideration of annual breast MRI to begin 10 years prior to youngest family member but not less than age 30
  • Consideration of additional risk reduction strategies, such as chemoprevention
MALE (cancer risk up to 1%6 by age 70):
  • No current screening guidelines exist

In this particular case…

This Ob-Gyn was able to correctly stratify the patient’s cancer risk, ruling out a hereditary cause with a negative hereditary cancer multi-gene panel test result. Importantly, this Ob-Gyn is still managing her differently than those in the sporadic category with general population risk.

Without this knowledge, provider may have assumed a genetic link and prescribes a treatment that is too aggressive, OR under-treats her without considering her elevated risk to develop breast and other cancers due to her familial risk. Instead of delaying her screening with mammography until the age of 40, based on the family history alone this patient can now benefit from routine annual mammograms and MRIs to help prevent cancer or detect it in an early stage, where it still can be treated. It addition, this patient now qualifies for an extra clinical breast exam each year.


References

  1. For the most up-to-date general population, gene-associated cancer risks, management criteria, and other syndrome-related cancers not listed here refer to the Gene Tables located at https://www.MyriadPro.com/myRisk. Risks are for patients who have never had cancer. Patients with hereditary risk may have increased risk for other syndrome related cancers.
  2. Metcalfe KA, et al. Br J Cancer. 2009 Jan 27;100(2):421-5.Epub 2008 Dec 16.
  3. Sutcliffe, et al. Int J Cancer. 2000 Jul 1;(87)1:110-7.
  4. ACOG Committee Opinion: Hereditary Cancer Syndromes and Risk Assessment, No. 634. June 2015.
  5. NCCN Clinical Practice Guidelines in Oncology: Breast Cancer Screening and Diagnosis. V2. 2016.

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