The Relationship Between Statins & Cancer
- Statins are a cholesterol-lowering medication.
- People who already take statins for a prescribed reason may have better cancer outcomes than people who need statins but don’t take them.
- There’s currently no evidence that statins make a difference in cancer risk or cancer death for people who don’t otherwise need statins.
The new study joins numerous other large studies that ask "Do they or don't they?" about whether statins could play a role in cancer prevention or treatment. But, the studies don't all approach the question in the same way, so there's no way they can arrive at a definitive answer.
Read MoreWomen Who Take Their Statins As Prescribed May Be Less Likely to Die From Cancer
In the recent study, researchers kept track of more than 38,000 women with newly diagnosed breast cancer, colorectal cancer, or melanoma, who were already prescribed statins for a pre-existing problem, usually high cholesterol. They followed the women for ten years and found that the better they were at taking their statins, the lower their risk of death from cancer.
While it may appear that statins helped the women survive cancer, "there are several reasons the study may have gotten these results," says Tworoger, who is director of population science at Moffitt Cancer Center.
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First, she says, "People who take their medications as prescribed, may be more likely to adhere to other recommendations their doctor makes, whether those are other medical recommendations, lifestyle recommendations, like quitting smoking or exercising." In other words, taking their statins every day may mean that they are making all kinds of other healthy choices every day, too. This overall healthier lifestyle could be what's helping these women survive cancer.
People who don't take their medication as prescribed could face numerous barriers to doing so. Any of these barriers could impact their cancer survival, too.
It could also be that because their cholesterol is under control, they do better. "There is some evidence that, in certain kinds of cancer, metabolic disease [a group of conditions that includes high cholesterol] can be associated with worse outcomes, so it may be that better controlling your cholesterol could actually improve your cancer outcomes."
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What's more, statins do other things than just lower cholesterol. They lower levels of other fats that circulate in the bloodstream, including a certain type that might play a role in some cancers. They interaction with the immune system, too.
"They can help the immune system and also suppress the immune system in different ways." Tworoger says. "We don't know which ones might be important for cancer."
Statins Unlikely to Have Cancer-Related Benefits for People Who Don't Need Them
Numerous other studies compare the cancer rates and cancer deaths of people who take statins because they need them with people who don't take statins because they don't need them. This comparison is quite different from the comparison made in the recent study. The recent study looks only at women prescribed statins and compares those who take them as prescribed to those who don't.
"There's a reason that people need to be on statins and that makes them different from people who don't need to be," Tworoger explains.
Studies that compare the cancer outcomes of people who take statins as prescribed to people who don't need statins don't seem to find any cancer-related benefits of the cholesterol-lowering drugs. They don't appear to lower cancer risk or cancer death rates.
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Another study compares people who started statins within six months of their cancer diagnosis to those who did not. Likewise, there was no difference in death rates among these two groups. This group is also different from the women in the recent study because the women were already taking statins before they learned they had cancer.
"Starting a medication after diagnosis can be totally different because it is interacting with the cancer," Tworoger says.
Similarly, a different experiment added statins to chemotherapy treatment for small cell lung cancer. Again, the cholesterol medication didn't make a difference.
The Bottom Line on Statins
Based on the findings of this varied group of studies, Tworoger lays out the take-home message on statins for people who have cancer.
"If you are a cancer patient and your doctor has prescribed you statins for a medical condition like high cholesterol, it's important to continue taking that medication as prescribed. It may improve your cancer outcomes, and it's unlikely to make things worse," she says. "But, there's no evidence at this time to suggest that people who don't need statins would benefit from them as a part of cancer treatment."
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