COMMENTARY

Another Look at Statins and Breast Cancer Recurrence

Lidia Schapira, MD

Disclosures

September 02, 2011

Statin Prescriptions and Breast Cancer Recurrence Risk: A Danish Nationwide Prospective Cohort Study

Ahern TP, Lars Pedersen L, Tarp M, et al
J Natl Cancer Inst. 2011;103:1-8

Background

Statins, a class of drugs that block cholesterol synthesis, may affect the development or outcomes of diseases other than cardiac disease, including cancer. Although most reports suggest no association between breast cancer incidence and statin use, few studies have investigated the relationship between breast cancer recurrence and statin use.

Study Summary

Ahern and coworkers conducted a nationwide, population-based prospective cohort study of all women residing in Denmark who were diagnosed with stage I-III invasive breast carcinoma that was reported to the Danish Breast Cancer Cooperative Group (DBCG) registry between 1996 and 2003 (n = 18,769). Women were followed for a median of 6.8 years after diagnosis. Prescriptions for lipophilic and hydrophilic statins were ascertained from the national electronic pharmacy database. Associations between statin prescriptions and breast cancer recurrence were estimated using generalized linear models and Cox proportional hazards regression; adjustments were made for the following factors: age and menopausal status at diagnosis; histologic grade; estrogen receptor status; receipt of adjuvant therapy; type of primary surgery received; pre-diagnosis hormone replacement therapy; and co-prescriptions of aspirin, angiotensin-converting enzyme inhibitors, nonsteroidal anti-inflammatory drugs, or anticoagulants. All statistical tests were 2-sided.

Most prescriptions for lipophilic statins in the study population were for simvastatin. At a follow-up of 10 years, exclusive simvastatin users experienced approximately 10 fewer breast cancer recurrences per 100 women (adjusted 10-year risk difference, 20.10; 95% confidence interval [CI] 20.11-20.08), compared with women who were not prescribed a statin. Exclusive hydrophilic statin users had approximately the same risk for breast cancer recurrence as women who were not prescribed a statin on follow-up (adjusted 10-year risk difference, 0.05; 95% CI, 20.01-0.11).

The investigators found that simvastatin, a highly lipophilic statin, was associated with a reduced risk for breast cancer recurrence in Danish women diagnosed with stage I-III breast carcinoma, whereas no association between hydrophilic statin use and breast cancer recurrence was observed.

Viewpoint

The prevalence of statin use in men and women older than 30 years of age has increased, and its potential risk modulating effect on other diseases -- such as cancer -- has generated considerable interest. Only 1 previous study has examined the association between post-diagnosis statin use and breast cancer recurrence.

The multinational team of investigators tapped into the amazing resources provided by the DBCG to investigate a possible link between the use of statins and risk for breast cancer recurrence. The chief strengths of this study are its large size, prospective design, and the use of high-quality prescription and clinical registry data. The DBCG registry combines the advantages of data validity and completeness of follow-up in a clinical trial with the advantages of studying a nearly complete and unselected source population.

Their findings may seem discordant with earlier meta-analyses that found no association between statin use and breast cancer incidence. This study identified a statistically significant reduction in breast cancer recurrence among users of lipophilic statins, which was not affected by other treatment modalities or known variables reflecting disease biology. The investigators acknowledged that receiving a statin prescription was assumed to be equivalent to taking the medication, although the actual compliance was not ascertained. However, because records are logged in the registry only after a patient has presented a prescription to a pharmacist and paid for the dispensed medication, it is reasonable to assume that these patients were compliant.

Results from this large prospective cohort study provide rationale for a clinical trial to evaluate lipophilic statins as adjuvant therapy for breast cancer. In the interim, it seems best to prescribe simvastatin in preference to other statins, all other considerations being equal.

Abstract

Comments

3090D553-9492-4563-8681-AD288FA52ACE
Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as:

processing....