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."