Statins May Improve Response to Radiotherapy in Patients With Hard-to-Treat Breast Cancers

According to a retrospective study and a registry analysis, statin therapy may reduce the rate of local breast cancer recurrence in certain types of breast cancer.

In patients with inflammatory breast cancer, supplementing radiation therapy with statin therapy could improve the rate of local recurrence—free survival.¹

Researchers Wendy Woodward, MD, PhD, Lara Lacerda, PharmD, PhD, and colleagues at the University of Texas MD Anderson Cancer Center retrospectively examined outcomes with and without statin therapy in 519 patients with inflammatory breast cancer (IBC).¹ In the study, statin therapy was associated with a lower likelihood of locoregional recurrence over 3 years.

In another analysis, investigators found a relationship between improved local recurrence—free survival and statin use in triple-negative breast cancer (a type of breast cancer that lacks 3 therapeutic targets—progesterone, estrogen, and HER2 receptors).^1,2

To date, inflammatory breast cancer, and triple-negative breast cancer lack treatment options that improve patient response to radiation therapy (also known as radiosensitizing agents). Results of this study indicate that statins may improve the efficacy of radiation therapy, although it is important to remember the study's limitations: a retrospective design, and the fact that a relatively low percentage (about 10%) of patients in the analysis were receiving statin therapy.^2,3

Investigation of the use of statins for inflammatory breast cancer is not without precedent. A Danish study published by Ahern et al published in 2011 showed a possible benefit of statin therapy. In the 18,769-patient registry study of breast cancer, patients were followed for a median of 6.8 years.⁴

Ahern and colleagues found that in 100 women treated for 10 years, statin therapy would prevent 10 cases of breast cancer recurrence. Importantly, the benefit was only detectable for statins that distribute well in fat (lipophilic statins), including simvastatin, lovastatin, and fluvastatin. The benefits did not extend to treatment with hydrophilic statins, such as atorvastatin, pravastatin, and rosuvastatin.⁴

In a press release, researchers noted the importance of the relationship found in the Denmark study.¹

“Our curiosity was piqued by the Denmark study and we also began looking at statins and found they seemed to improve survival in IBC patients,” Dr. Lacerda said in the release.

The results of the retrospective analysis by Lacerda and colleagues would be less remarkable if the researchers had not also studied the effects of simvastatin in breast cancer cell lines. Researchers irradiated cells from inflammatory breast cancer and triple-negative breast cancer tumors. Presence of simvastatin improved the cancer cells’ response to radiotherapy in both cell lines. This result indicates a possible mechanism for the activity of statins, and points to a direct effect of statins in sensitizing breast cancer cells to radiation.²

Although data in cell lines is compelling evidence for causal association between statins and improved outcomes, to date, the benefits of statins in inflammatory and triple-negative breast cancer have only been validated in retrospective trials. Prospective trials will be necessary to validate these findings before radiosensitizing statin therapy becomes part of clinical practice.²

References:

• Cholesterol Drug and Radiation Combo Could Halt Recurrence of Aggressive Breast Cancer. http://www.prweb.com/releases/2014/06/prweb11920556.htm. Accessed June 2014.
• Lacerda L, Reddy JP, Liu D, et al. Simvastatin Radiosensitizes Differentiated and Stem-Like Breast Cancer Cell Lines and Is Associated With Improved Local Control in Inflammatory Breast Cancer Patients Treated With Postmastectomy Radiation. Stem Cells Transl Med. 2014.
• Fornier M, Fumoleau P. The paradox of triple negative breast cancer: novel approaches to treatment. Breast J. 2012;18(1):41-51.
• Ahern TP, Pedersen L, Tarp M, et al. Statin prescriptions and breast cancer recurrence risk: a Danish nationwide prospective cohort study. J Natl Cancer Inst. 2011;103(19):1461-1468.