Hereditary Breast Cancer Summary
In summary, the identification of a germline BRCA mutation in a woman with breast or ovarian cancer should not, at present, influence her local or systemic treatment. The recognition of a hereditary breast or ovarian cancer, however, indicates the need for specialized surveillance and prevention strategies to manage subsequent cancer risk in that woman and in her female relatives.
Males in such families may also benefit from heightened surveillance for colon, prostate and possibly breast cancer. The choice of whether or not to undergo genetic testing is a difficult one and should only be made after genetic counseling by a qualified professional.
Such professionals should also be involved in the interpretation of genetic test results. Such expertise is necessary because the integration of test results into a cancer risk assessment is a complex endeavor, particularly if results are “negative” in the setting of a strong family history or if the results are ambiguous (genetic variants of uncertain significance).
Although the feared social risks of genetic testing appear not to have materialized in any systematic way, the psychosocial consequences and impact upon family dynamics are important considerations that are still being defined. Finally, the medical management of individuals at highest hereditary risk is being continuously refined. A new era of genetically targeted risk management has dawned, and much research is required to maximize the benefits of this technology for families at risk.
Note
We have recently published an evaluation of 305 unselected women of Ashkenazi descent undergoing breast-conservation therapy for a total of 329 invasive breast cancers.
Using an anonymized design, outcomes of 28 women with founder mutations in BRCA1 or BRCA2 were compared to those of women without mutations. Overall, women with mutations fared poorer than those without, with 10 year breast-cancer-specific survival of 71.9% compared to 87.2% in those without. After adjustment for tumor size and nodal status, however, mutation status was not an independent predictor of worse survival. These results, using a study design that avoids the survival biases inherent in other series, suggest that women with certain specific BRCA mutations tend to present at a more advanced stage than women without such mutations, although it remains unclear if this tendency for more advanced presentation is a result of a lack of screening among younger women or a consequence of a more aggressive biology.
Mark E. Robson
Breast conservation therapy for invasive breast cancer in Ashkenazi women with BRCA gene founder mutations. J Natl Cancer Inst 2003
References
- Newman B, Austin MA, Lee M et al. Inheritance of human breast cancer: Evidence for autosomal dominant transmission in high-risk families. Proc Natl Acad Sci USA 1988; 85:3044-3048.
- Hall JM, Lee MK, Newman B et al. Linkage of early-onset familial breast cancer to chromosome 17q21. Science 1990; 250:1684-1689.
- Narod SA, Feunteun J, Lynch HT et al. Familial breast-ovarian cancer locus on chromosome 17q12-q23. Lancet 1991; 338:82-83.
- Steichen-Gersdorf E, Gallion HH, Ford D et al. Familial site-specific ovarian cancer is linked to BRCA1 on 17q12-21. Am J Hum Genet 1994; 55:870-875.
- Miki Y, Swensen J, Shattuck-Eidens D et al. A strong candidate for the breast and ovarian cancer susceptibility gene BRCA1. Science 1994; 266:66-71.
- Wooster R, Neuhausen SL, Mangion J et al. Localization of a breast cancer susceptibility gene, BRCA2, to chromosome 13q12-13. Science 1994; 265:2088-2090.
- Wooster R, Bignell G, Lancaster J et al. Identification of the breast cancer susceptibility gene BRCA2. Nature 1995; 378:789-792.
- Zhang H, Tombline G, Weber BL. BRCA1, BRCA2, and DNA damage response: Collision or collusion? Cell 1998; 92:433-436.
- Malone KE, Daling JR, Thompson JD et al. BRCA1 mutations and breast cancer in the general population: Analyses in women before age 35 years and in women before age 45 years with first-degree family history. JAMA 1998; 279:922-929.
- Newman B, Mu H, Butler LM, Millikan RC et al. Frequency of breast cancer attributable to BRCA1 in a population-based series of American women. JAMA 1998; 279:915-921.
- Berchuck A, Heron KA, Carney ME et al. Frequency of germline and somatic
- BRCA1 mutations in ovarian cancer. Clin Cancer Res 1998; 4:2433-2437.
- Rubin SC, Blackwood MA, Bandera C et al. BRCA1, BRCA2, and hereditary nonpolyposis colorectal cancer gene mutations in an unselected ovarian cancer population: Relationship to family history and implications for genetic testing. Am J Obstet Gynecol 1998; 178:670-677.
- Stratton JF, Gayther SA, Russell P et al. Contribution of BRCA1 mutations to ovarian cancer. N Engl J Med 1997; 336:1125-1130.
- Szabo CI, King MC. Population genetics of BRCA1 and BRCA2. Am J Hum Genet 1997; 60:1013-1020.
- Ford D, Easton DF, Stratton M et al. Genetic heterogeneity and penetrance analysis of the BRCA1 and BRCA2 genes in breast cancer Families. Am J Hum Genet.1998; 62:676-689.
- Tonin P, Weber B, Offit K et al. Frequency of recurrent BRCA1 and BRCA2 mutations in Ashkenazi Jewish breast cancer families. Nat Med 1996; 2:1179-1183.
- Struewing JP, Hartge P, Wacholder S et al. The risk of cancer associated with specific mutations of BRCA1 and BRCA2 among Ashkenazi Jews. N Engl J Med 1997; 336:1401-1408.
- ...