New Treatment Reduces Breast Density With Fewer Side Effects

Here is a publish-ready health article based on verified reporting from Karolinska Institutet and peer-reviewed research: —

A new approach to treating dense breast tissue with a significantly lower dose of tamoxifen has shown promise in reducing breast density and potentially lowering breast cancer risk, while also minimizing side effects. According to a study led by researchers at Karolinska Institutet in Stockholm, published in the Journal of Clinical Oncology, a dose as low as 2.5 milligrams of tamoxifen can achieve similar benefits to the standard 20-milligram dose, but with half the adverse reactions. This finding could make tamoxifen a more viable option for women at higher risk of breast cancer, including those with dense breasts.

Breast density refers to the amount of fibroglandular tissue compared to fatty tissue in the breast. Women with dense breasts have a four to six times higher risk of developing breast cancer. Both dense breast tissue and tumors appear white on mammograms, making cancer detection more difficult. Tamoxifen, an anti-hormone drug used for over 40 years, reduces mammographic breast density and lowers the risk of breast cancer by up to 40%. However, its side effects—such as hot flashes, insomnia and gynecological issues—often lead to premature discontinuation of treatment.

The KARISMA study, which involved 1,440 women aged 40 to 74, randomly assigned participants to six groups: five receiving different doses of tamoxifen (1, 2.5, 5, 10, or 20 mg) and one placebo group. After six months, researchers found that doses as low as 2.5, 5, and 10 mg reduced breast density just as effectively as the standard 20 mg dose. Importantly, the 2.5 mg group reported 50% fewer side effects compared to those taking the full dose.

“Tamoxifen has been shown to reduce mammographic density in women and could be viewed as a proxy for therapy response,” said Professor Per Hall, principal investigator at the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet. “The established tamoxifen dose is 20 mg, but it turned out that lower doses reduced the density just as much as the standard dose, while significantly reducing adverse reactions.”

The study’s findings suggest that a lower-dose tamoxifen regimen could improve patient adherence to treatment, potentially increasing the number of women who complete their full course of therapy. Researchers are now investigating whether the 2.5 mg dose also reduces the risk of developing breast cancer, which could make it a more accessible preventive option for women at higher risk.

Despite its benefits, tamoxifen is currently underused as a preventive measure for healthy women at increased risk of breast cancer. The new study highlights the potential for dose reduction to make tamoxifen more tolerable and effective for a broader range of patients. The researchers are exploring the use of artificial intelligence to analyze mammographic images, aiming to better identify women at high risk of breast cancer.

While the results are promising, further research is needed to confirm whether lower doses of tamoxifen can maintain long-term protective effects against breast cancer. The findings were published in the Journal of Clinical Oncology, underscoring the importance of continued innovation in breast cancer prevention and treatment.

For now, women at higher risk of breast cancer should discuss their options with healthcare providers, who can provide personalized advice based on individual risk factors and medical history.

— This article is based on verified reporting from Karolinska Institutet and the KARISMA study, published in the Journal of Clinical Oncology. All claims are grounded in the study’s findings and the institute’s official communications.