NEW YORK, March 1 (UPI) -- A study of 251 people identified as having a gene mutation that puts them at higher risk for breast and ovarian cancer shows it is possible to use genetic testing as part of a strategy to identify cancers early.
The study, done at Memorial Sloan-Kettering Cancer Center in New York, reports genetic counseling, testing and an increased level of surveillance coupled with risk-reducing surgeries resulted in the diagnosis of early stage tumors much more often than would otherwise occur.
The study, published Friday in the Journal of Clinical Oncology, is the first to follow breast and ovarian cancer screening and preventive surgery in a group this large that has BRCA gene mutations.
The two genes identified, with BRCA 1 and BRCA2 mutations, occur in a frequency of about 1 in 345 people in the general population in the United States and in about 1 person in 40 among people of Jewish background who emigrated to the U.S. from eastern and central Europe, often referred to as Ashkenazi Jews.
The gene in its normal form helps to suppress cancer but with the BRCA1 or BRCA2 mutation loses much of that ability. People with the BRCA mutation have an increased risk for breast cancer about 20 times as great as those without the mutation. The risk for ovarian cancer is nine times as great. Males with the mutation also are at increased risk for breast cancer.
All subjects in the study knew they had the gene. Twenty-nine of 233 women in the study chose to have risk-reducing mastectomies after testing. Two were found to have undetected intraductal breast cancers. Ninety women chose to have their ovaries and fallopian tubes removed, a procedure called salpingo-oophorectomy. One early stage ovarian cancer and one early stage fallopian tube cancer -- rarely found in early stages -- were discovered.
Radiographic screening detected six breast cancers, most in early stages and six additional breast cancers were found through physical examinations.
Deborah Armstrong, assistant professor of oncology and gynecology and obstetrics at the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins in Baltimore, Md., said: "We didn't have any good data that identification of patients at high risk led to an improvement in outcome for those patients. Now we know."
The process followed in the study caught breast and ovarian cancers much earlier than would have otherwise occurred, she said. Armstrong said the study also highlighted the importance of physical examination.
The authors said a limitation of the study was only having followed the individuals for two years and the fact the study was confined to one institution and with highly motivated participants.
Kenneth Offit, one of the researchers who is chief of the clinical genetic service at Memorial Sloan-Kettering, said it is possible much higher rates of ovarian cancers would have been found in a similar group not enrolled in a surveillance program.
"For me, the biggest surprise of this study was the ability to find those ovarian cancers," he said. The findings point to the limitations of early stage screening for ovarian cancers, he added. One ovarian cancer was found in a woman with normal ultrasound and biochemical assay for ovarian cancer.
Patricia Ganz, director of the division of cancer prevention and control research of the Jonsson Comprehensive Cancer Center at the University of California at Los Angeles said the study was interesting and valuable, but noted one shortcoming.
"Because they were not compared to a group of (BRCA) individuals who had less intensive surveillance or were less likely to have the preventive surgeries, we can't say with any confidence that this has changed the outcome for patients," she said.
Ganz said, however, knowing one is a carrier of a BRCA mutation is an empowering piece of information because one can take preventive measures such as having surgery or taking medication or having more intense surveillance to help reduce risks.
(Written by Joe Grossman in Santa Cruz, Calif.)
