Statins work like a vigilant janitor: they block an enzyme in the liver that produces cholesterol, much like a janitor might simply turn off a leaky faucet to prevent a room from flooding. Statins are firmly established in cardiovascular medicine for preventing heart attacks and strokes because they reduce cholesterol. Now, what is even more fascinating is that people taking statin medication have lower incidences of certain types of cancer and even better survival rates if they do get cancer. Statins can trigger a sort of self-destruct sequence in cancer cells, known as apoptosis. Imagine our janitor finding a fire alarm that only goes off in rooms where small fires are starting. This alarm helps extinguish the fire without affecting the rest of the building. Similarly, statins can signal cancer cells to die off, leaving healthy cells unharmed. Another critical factor in tumor growth is the formation of new blood vessels, or angiogenesis, which acts like new pathways for the fire to spread. Statins can inhibit this process, much like our janitor blocking off hallways to prevent a fire from moving to other parts of the building.
A recent study from the Li group, published in the journal Cancer, explored the association between the use of statins and whether breast cancer recurs or results in death. "Our study helps clarify conflicting evidence from previous studies by employing rigorous methodologies to minimize potential biases," re-emphasized Dr. Guo, lead author of the study. If statins are shown to be effective in reducing breast cancer mortality, they would be a valuable additive to the existing treatment modalities, being safe, inexpensive and readily available for patients' use.
Dr. Hanbing Guo, Dr. Christopher Li, and colleagues from Fred Hutchinson Cancer Center used data from the SEER-Medicare linked database in a retrospective cohort study. This database combines information from two significant population-based sources of data, providing a comprehensive dataset about elderly persons with cancer. Dr. Guo stated that the "…use of the nationally-representative SEER-Medicare database means that our findings are highly generalizable to the elderly US patient population."
The study involved more than 38,800 women, all aged 66 years and older, who had been diagnosed with localized and regional-stage breast cancer between 2008 and 2017. The team looked particularly at those women who had filled a minimum of two prescriptions of statins following their breast cancer diagnosis. The two main things to be established by this study are whether the cancer came back and mainly, whether, amongst the women, an outcome of death occurred as a result of breast cancer.
The findings of this study revealed some important insights about how statin usage might change the outcome of breast cancer. On a general scale, it was established that usage of statins following diagnosis of breast cancer did not affect the risk of recurrence of cancer. This applied to all types of breast cancer and also for various periods and doses of statin use. It, however, indicated that the risk of death from breast cancer was lower by 15% among female statin users. More in-depth analysis showed that this protective effect was particularly significant in women with hormone receptor-positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) breast cancer. When a breast cancer is hormone receptor-positive (HR+), that would imply that the cancer cells use hormones like estrogen or progesterone to fuel growth. These cancers grow slowly and can often be treated effectively with therapy that targets the hormone receptors. Human epidermal growth factor receptor 2-negative (HER2-) breast cancer cells, on the other hand, have little amount or no HER2 protein on their surface, meaning treatments targeting HER2 won't work on these cancers.
Another interesting observation from the study is that the longer the duration of statin use, the greater the reduction in breast cancer-specific mortality. This suggests that sticking with statin therapy over a longer period could bring even greater benefits in terms of survival.
These findings suggest that statins, particularly among older women with localized or regional breast cancer, can serve as effective adjunct therapy in the increase of breast cancer-specific survival. This would be particularly important since statins are currently very widely used and generally have a very favorable safety profile. Dr. Guo explained, “while our study adds to the growing evidence of an association between statin use and improved breast cancer survival, ultimately our findings should be validated in clinical trials of statin therapy in patients with breast cancer.” Such trials would help eliminate biases inherent in observational studies. Taking note of such results, Dr. Guo said, “given the relatively short follow-up period in this study, future research with longer follow-up is needed to investigate the long-term effects of statin therapy on breast cancer outcomes, particularly on breast cancer recurrence.” If this is confirmed, statins could become a precious supplement in the increasingly extensive armamentarium for the treatment of breast cancer patients, providing a safe and low-cost strategy to increase survival rates.
This study received support through grants from the National Cancer Institute (NCI).
Guo, H., Malone, K. E., Heckbert, S. R., & Li, C. I. (2024). Statin use and risks of breast cancer recurrence and mortality. Cancer, 10.1002/cncr.35362. Advance online publication.