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Cancer Genetics Risk Assessment and Counseling (PDQ®): Genetics - Health Professional Information [NCI] - Components of the Risk Assessment Process

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A three-generation family history includes the following:

  • First-degree relatives (e.g., children, brothers and sisters, and parents).
  • Second-degree relatives (e.g., grandparents, aunts and uncles, nieces and nephews, grandchildren, and half-siblings).
  • Third-degree relatives (e.g., first cousins, great aunts, and great uncles).
  • Additional distant relatives are included if information is available, especially when there are known cancer histories among them.

For any relative with cancer, collect the following information:[34]

  • Primary site of each cancer, with supportive documentation of key cancers (if available) to confirm primary site and histology (e.g., pathology reports, clinical documents, and death certificates).
  • Age at diagnosis for each primary cancer.
  • Where the relative was diagnosed and/or treated.
  • History of surgery or treatments that may have reduced the risk of cancer. For example, bilateral salpingo-oophorectomy in a premenopausal woman significantly reduces the risk of ovarian and breast cancers. This may mask underlying hereditary predisposition to these cancers.
  • Current age (if living).
  • Age at death and cause of death (if deceased).
  • Carcinogenic exposures (e.g., tobacco use and radiation exposure).
  • Other significant health problems.

For relatives not affected with cancer, collect the following information:

  • Current age or age at death.
  • Cause of death (if deceased).
  • History of any surgeries or treatments that may have reduced the risk of cancer.
  • Cancer screening practices.
  • Any nonmalignant features associated with the syndrome in question.
  • Carcinogenic exposures.
  • Other significant health problems.

Accuracy of the family history

The accuracy of the family history has a direct bearing on determining the differential diagnoses, selecting appropriate testing, interpreting results of the genetic tests, refining individual cancer risk estimates, and outlining screening and risk reduction recommendations. In a telephone survey of 1,019 individuals, only 6% did not know whether a first-degree relative had cancer; this increased to 8.5% for second-degree relatives.[35] However, people often have incomplete or inaccurate information about the cancer history in their family.[31,32,34,36,37,38,39,40,41] A population-based survey of 2,605 first- and second-degree relatives and confirmed proband reports of cancer diagnoses found that the accuracy of reported cancer diagnoses in relatives was low to moderate, while reports of no history of cancer were accurate.[41] Accuracy varies by cancer site and degree of relatedness.[41,42] Reporting of cancer family histories may be most accurate for breast cancer [41,43] and less accurate for gynecologic malignancies [41,43] and colon cancer.[41] Self-reported family histories may contain errors and, in rare instances, could be fictitious.[39,43,44] It is important to confirm the primary site of cancers in the family that will affect the calculation of hereditary predisposition probabilities and/or estimation of empiric cancer risks, especially if decisions such as risk-reducing surgery will be based on this family history.[44] The most reliable documentation of cancer histology is the pathology report. Verification of cancers can also be made through other medical records, tumor registries, or death certificates.

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WebMD Public Information from the National Cancer Institute

Last Updated: February 25, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
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