Danish cancer patients taking cholesterol-lowering statin drugs were 15% less likely to die, of cancer or any other cause, than patients who were not on the popular medications, in a new study.
The pattern held regardless of a person's age, cancer type, tumour size or whether it had spread. Only patients who had received chemotherapy showed no apparent benefit from taking statins - the most commonly-prescribed drugs in the world.
Eric Jacobs, a researcher at the American Cancer Society who was not involved in the new work, called the findings "intriguing and exciting" but said they "do not mean that people with cancer should start using statins in the hopes of improving their progress."
The study, published in the New England Journal of Medicine, did not look at whether the statins, including familiar brand names such as Lipitor and Mevacor, can prevent cancer - only at what happens once cancer is diagnosed.
Using multiple registries containing data on cancer, drug use, population characteristics and deaths for the nation of Denmark, the research team analysed the cancer cases of 18 721 people over age 40 who were diagnosed between 1995 and 2007.
All were taking statins regularly before their cancer was discovered, and the study compared them to 277 204 people who had not regularly taken the drugs before getting cancer treatments.
Overall, the cancer death rate among statin users was 15% lower, and so was the rate of death from any cause.
Statins to be considered
The appearance of a benefit from taking statins was strongest for 13 cancer types in particular, ranging from an 11% lower death rate among pancreatic cancer patients to a 36% lower rate among cervical cancer patients. For 14 other tumour types, the results were less clear-cut.
The study's senior author, Dr Stig Bojesen of the University of Copenhagen compared the difference in mortality to that seen with chemotherapy. "The benefit of receiving chemotherapy versus not receiving chemotherapy is 15% to 20%, depending on cancer type," he said. "What we see (in the new study) is comparable to that. That's really something."
The fact that a seeming benefit from statins was not seen in people taking chemotherapy, however, doesn't mean that people should avoid chemotherapy treatment and turn to statins instead, Bojesen stressed.
Rather, he thinks therapeutic use of statins might be considered when no good chemotherapy option is available for a particular cancer type.
And, if his team's finding is confirmed in a larger study, statins may offer an easy, inexpensive way to reduce cancer deaths in some patients, he added.
Because the drugs are available in generic form, "The daily cost is about 10 cents or something like that. It's extremely cheap," Bojesen said.
An estimated one in four Americans over age 45 takes statin drugs, which work in the liver to reduce the amount of "bad" cholesterol in the bloodstream.
Bojesen speculates that the drugs may be robbing cancer cells of an important building block of cell membranes, and thereby slowing tumour growth.
"Our hypothesis is that by reducing cholesterol, you steal cholesterol from the proliferating cancer cells improving survival," he said.
But there is cause for scepticism. The people who took less than the recommended dose of a statin had a higher rate of survival than cancer patients who took higher doses. A positive relationship between dose and response is usually seen as some evidence of cause and effect.
"The absence of a dose trend might indicate that just some statin might be enough," Bojesen said. "But this is just an observational study, so the exact dose and the exact mechanism is something we can't clarify with this paper."
In an editorial accompanying the new report, Dr Neil Caporaso of the National Cancer Institute said the study is also limited because no information on factors such as smoking were available.
So, for instance, the higher likelihood that people taking statins had heart disease and might therefore have also been targeted for smoking cessation treatment, would muddy the connection between being on statins and having lower cancer mortality.
In addition, information on treatment with chemotherapy and radiation were missing for 72% of the people taking statins, he noted.
"Because this study was an observational study, the slightly lower cancer death rates among cancer patients who had used statins before their cancer diagnosis could have been caused by factors other than the statin itself," Jacobs said. For example, he said, "People using statins may have been more likely to use aspirin, which has been linked with improved cancer survival in some recent studies."
(Reuters Health, November 2012)
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