A new study is offering the most detailed investigation to date into the relationship between breast cancer survival and statins – common cholesterol-lowering drugs. The retrospective study saw a 58 percent greater survival rate in breast cancer patients taking statins.
"There is already a body of literature on statins and breast cancer and the results have been inconsistent," says Kevin Nead, lead researcher from the University of Texas. "Previous research has looked at breast cancer as only one disease, but we know there are many subtypes of breast cancer and we wanted to focus our research on this particularly aggressive form of breast cancer that has limited effective treatment options."
There are three receptors commonly found in many breast cancers which present helpful targets for drugs to home in on. Around 15 percent of breast cancers, however, lack any of these common receptor targets. These are known as triple-negative breast cancers, and they are harder to treat than other types.
The new research looked at data from 23,192 women with breast cancer. The focus was on incidental statin use, which was defined as statin use that began in the year following the initial breast cancer diagnosis.
The results showed those incidental statin users were 58 percent more likely to survive their breast cancer with a median follow-up period of around three years. The association between survival and statins was strongest in women with early-stage triple-negative breast cancer taking a high dose of statins. The study also found increased overall survival rates in patients specifically taking lipophilic statins.
Exactly how statins could be increasing survival rates in breast cancer patients is still unclear. A study from the American Heart Association published earlier this year suggested statin use may decrease heart muscle damage caused during chemotherapy, which could increase overall survival rates in the years following breast cancer recovery.
But it is also plausible statins may also be acting directly on cancer cells in some way. Research last year from Johns Hopkins Medicine found statins can directly induce cell death in cancers with a particular gene mutation. Importantly, this research was only conducted in lab cultures of engineered cells so there is still not good evidence of statins directly interacting with cancer cells in human patients.
Nead says it is time to conduct specific prospective research on the potential role of statins in breast cancer treatment, particularly in the context of triple-negative breast cancer.
"We know that statins decrease breast cancer cell division and increase cell death," says Nead. "Our study shows that there is an association between statins and improved outcomes in TNBC, and it is time to pursue this idea further in a prospective trial."
The new study was published in the journal Cancer.
