Most breast cancers not linked to ovarian cancer

BRCA mutation-related Breast cancers are known to greatly increase the risk of ovarian cancer, but new research indicates this association does not apply to other types of hereditary Breast cancer.

"I think this is very good news," said Dr. Noah D. Kauff , adding that about 50 percent of all hereditary Breast cancers are not related to BRCA mutations. Also, most cases of Breast cancer are sporadic, developing in women with no known genetic risk factors.

Although confirmatory studies are needed, he said, the findings of this study suggest that removal of the ovaries, as a preventive measure, is "unnecessary for women with a family history of Breast cancer who test negative for BRCA mutations."

Kauff, from Memorial Sloan Kettering Cancer Center in New York, explained that in recent years it has become common "to offer (surgical ovary removal) to women with a family history of Breast cancer, even without performing genetic testing." These findings, however, suggest that determining the BRCA status is useful to further classify these women to determine if this surgical procedure is really useful in preventing ovarian cancer.

The findings reported by Kauff and colleagues in the Journal of the National Cancer Institute, are based on a study of 165 families with multiple cases of BRCA mutation-negative breast cancer.

During an average of approximately 3.5 years of follow-up (ranging from 15 to 82 months), 19 new cases of Breast cancer were diagnosed compared with the 6.07 cases that would be expected in the general population. By contrast, the one case of ovarian cancer that occurred in the study group was not significantly different from the 0.66 cases that would be expected in the general population.

Kauff said he hopes and expects these findings to cause a drop in the usage of ovarian surgery among women with hereditary breast cancer. However, he noted that larger studies with longer follow-up are needed to know for certain that BRCA mutation-negative breast cancer does not increase the risk of ovarian cancer, even slightly.

SOURCE: Journal of the National Cancer Institute, September 21, 2005.