[Note: Many of the medical and scientific terms used in this summary are found in the NCI Dictionary of Genetics Terms. When a linked term is clicked, the definition will appear in a separate window.]
This summary describes current approaches to assessing and counseling people about their chance of having an inherited susceptibility to cancer. Genetic counseling is defined by the National Society of Genetic Counselors as the process of helping people understand and adapt to the medical, psychological, and familial implications of genetic contributions to disease. Several reviews present overviews of the cancer risk assessment, counseling, and genetic testing process.[1-4]
Individuals are considered to be candidates for cancer risk assessment if they have a personal and/or family history (maternal or paternal lineage) with features suggestive of hereditary cancer. These features vary by type of cancer and specific hereditary syndrome. Criteria have been published to help identify families who may benefit from a referral to genetic counseling.[2,6] The introductory sections of the PDQ cancer genetics information summaries on breast, ovarian, colorectal, prostate, skin, and medullary thyroid cancers describe the clinical features of hereditary syndromes associated with these cancers.
The following are features that suggest hereditary cancer:
- Unusually early age of cancer onset (e.g., premenopausal breast cancer).
- Multiple primary cancers in a single individual (e.g., colorectal and endometrial cancer).
- Bilateral cancer in paired organs or multifocal disease (e.g., bilateral breast cancer or multifocal renal cancer).
- Clustering of the same type of cancer in close relatives (e.g., mother, daughter, and sisters with breast cancer).
- Cancers occurring in multiple generations of a family (i.e., autosomal dominant inheritance).
- Occurrence of rare tumors (e.g., retinoblastoma, adrenocortical carcinoma, granulosa cell tumor of the ovary, ocular melanoma, or duodenal cancer).
- Unusual presentation of cancer (e.g., male breast cancer).
- Uncommon tumor histology (e.g., medullary thyroid carcinoma).
- Rare cancers associated with birth defects (e.g., Wilms tumor and genitourinary abnormalities).
- Geographic or ethnic populations known to be at high risk of hereditary cancers. Genetic testing candidates may be identified based solely on ethnicity when a strong founder effect is present in a given population (e.g., Ashkenazi heritage and BRCA1/BRCA2 mutations).[7,8]
As part of the process of genetic education and counseling, genetic testing may be considered when the following factors are present:
- An individual's personal history (including ethnicity) and/or family history is suspicious for a genetic predisposition to cancer.
- The genetic test has sufficient sensitivity and specificity to be interpreted.
- The test will impact the individual's diagnosis, cancer management or cancer risk management, and/or help clarify risk in family members.[9,10]
A candidate for genetic testing receives genetic education and counseling before testing to facilitate informed decision making and adaptation to the risk or condition. Genetic education and counseling gives an individual time to consider the various medical uncertainties, diagnosis, or medical management based on varied test results, and the risks, benefits, and limitations of genetic testing.
- Petersen GM: Genetic testing. Hematol Oncol Clin North Am 14 (4): 939-52, 2000. [PUBMED Abstract]
- Kuschel B, Lux MP, Goecke TO, et al.: Prevention and therapy for BRCA1/2 mutation carriers and women at high risk for breast and ovarian cancer. Eur J Cancer Prev 9 (3): 139-50, 2000. [PUBMED Abstract]
- Schoen RE: Families at risk for colorectal cancer: risk assessment and genetic testing. J Clin Gastroenterol 31 (2): 114-20, 2000. [PUBMED Abstract]
- Riley BD, Culver JO, Skrzynia C, et al.: Essential elements of genetic cancer risk assessment, counseling, and testing: updated recommendations of the National Society of Genetic Counselors. J Genet Couns 21 (2): 151-61, 2012. [PUBMED Abstract]
- Weitzel JN, Lagos VI, Cullinane CA, et al.: Limited family structure and BRCA gene mutation status in single cases of breast cancer. JAMA 297 (23): 2587-95, 2007. [PUBMED Abstract]
- Hampel H, Sweet K, Westman JA, et al.: Referral for cancer genetics consultation: a review and compilation of risk assessment criteria. J Med Genet 41 (2): 81-91, 2004. [PUBMED Abstract]
- Tobias DH, Eng C, McCurdy LD, et al.: Founder BRCA 1 and 2 mutations among a consecutive series of Ashkenazi Jewish ovarian cancer patients. Gynecol Oncol 78 (2): 148-51, 2000. [PUBMED Abstract]
- Beller U, Halle D, Catane R, et al.: High frequency of BRCA1 and BRCA2 germline mutations in Ashkenazi Jewish ovarian cancer patients, regardless of family history. Gynecol Oncol 67 (2): 123-6, 1997. [PUBMED Abstract]
- American Society of Clinical Oncology.: American Society of Clinical Oncology policy statement update: genetic testing for cancer susceptibility. J Clin Oncol 21 (12): 2397-406, 2003. [PUBMED Abstract]
- Robson ME, Storm CD, Weitzel J, et al.: American Society of Clinical Oncology policy statement update: genetic and genomic testing for cancer susceptibility. J Clin Oncol 28 (5): 893-901, 2010. [PUBMED Abstract]
- Genetic Counseling as a Profession. Chicago, IL: National Society of Genetic Counselors, 2006. Also available online. Last accessed December 8, 2011.