Press Releases: Southern California
October 19, 2004
Widely used breast cancer drug not linked to stroke
Study in JNCI suggests tamoxifen does not raise stroke risk among survivors
LOS ANGELES – Prompted by results of two previous studies, physicians warned breast cancer patients considering tamoxifen that the drug might increase their stroke risk—but a new study by California researchers finds no link between tamoxifen and stroke.
In a study published in the Oct. 20 Journal of the National Cancer Institute, Drs. Ann M. Geiger of Kaiser Permanente Southern California and Leslie Bernstein of the University of Southern California conducted a nested case-control study to assess the impact of tamoxifen treatment for breast cancer on stroke risk.
"Out of 11,045 women in the Kaiser Permanente Southern California system who were diagnosed with breast cancer from 1980 to 2000, and who had not experienced a prior stroke, 179 women had a verifiable stroke in the years after treatment and were included in the study," says Dr. Geiger. She continued, "We found that use of tamoxifen was not associated with risk of stroke, either overall or when grouped by duration of use, dose of the drug or how recently the drug was used."
However, use of chemotherapy—but not a specific chemotherapy regimen—was associated with a more-than-doubled risk of stroke, whether or not tamoxifen was used.
"The finding that chemotherapy increases stroke risk among women treated for invasive breast cancer was unexpected, and we are unsure why chemotherapy might be linked to stroke risk," says Dr. Bernstein. "In absolute terms, the risk of a stroke following breast cancer diagnosis is small, and our findings should not deter women from this treatment. Chemotherapy remains a key component of breast cancer therapy," she adds.
"Our study suggests that women and their clinicians considering tamoxifen use for breast cancer treatment can do so without concern for stroke," the authors conclude.
Although the association between chemotherapy and stroke risk must be further explored, the researchers note that women with a history of chemotherapy "may benefit from approaches to reduce stroke risk, such as appropriate management of hypertension and diabetes."
Ann M. Geiger, Glenn M. Fischberg, Wansu Chen and Leslie Bernstein, "Stroke Risk and Tamoxifen Therapy for Breast Cancer." Journal of the National Cancer Institute, Vol. 96, No. 20, Oct. 20, 2004.
About Kaiser Permanente
Kaiser Permanente is America's leading integrated health plan. Founded in 1945, it is a nonprofit, group practice prepayment program with Southern California headquarters in Pasadena, California. Kaiser Permanente serves the health care needs of 3.3 million members in Southern California. Today it encompasses the nonprofit Kaiser Foundation Health Plan, Inc., Kaiser Foundation Hospitals and their subsidiaries, and the for-profit Southern California Permanente Medical Group. Kaiser Permanente's Southern California Region includes more than 49,900 technical, administrative and clerical employees and caregivers, and more than 6,000 physicians representing all specialties. More information about Kaiser Permanente can be found at kaiserpermanente.org.
