When the BRCA1 and BRCA2 genes for breast and ovarian cancers were first identified and a screening blood test became available, a debate ensued as to whether there was an advantage to learning one’s risk. Recently, the value of such testing was demonstrated in a study in women who were followed after being identified as carriers of a BRCA genetic mutation. Researchers at Memorial Sloan-Kettering Cancer Center have provided strong evidence that breast and ovarian cancers can be detected at an early stage in women at highest hereditary risk. Results of the study were published in a recent issue of the Journal of Clinical Oncology (20:1260-1268, 2002).
"These results provide the first prospective evidence that BRCA testing can lead to interventions that result in the diagnosis of early-stage breast and ovarian cancers," said Dr. Kenneth Offit, chief of the Clinical Genetics Service at Memorial Sloan-Kettering and senior author of the study.
Intensified Screening, Prophylactic Surgery
The study enrolled 251 individuals, including 233 women identified as having mutations in the BRCA1 or BRCA2 genes. Participants received uniform recommendations for intensified screening and preventive surgery in the context of genetic counseling. Over the course of the study, 21 women were diagnosed with early breast or ovarian cancer.
Among the women identified as being at risk for breast cancer, 165 chose increased surveillance. Breast cancer was detected in 12 of these patients, with 9 of the tumors diagnosed at the earliest stage. Half of these breast cancers were detected by mammography (including one by magnetic resonance imaging) and half by physical examination during the interval between annual mammograms.
Moreover, to reduce their risk of developing breast cancer, 29 women chose to undergo prophylactic mastectomy. Of these women, two were found to have unsuspected early-stage breast cancer at the time of surgery.
"These results illustrate the importance of a comprehensive approach to breast cancer screening including self examinations in addition to breast imaging and physician examinations," said Lauren Scheuer, a senior genetic counselor at Memorial Sloan-Kettering and lead author of the study. "Further research is necessary to determine whether more frequent breast imaging may be warranted in women at hereditary risk."