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April 12, 2006 -- There is growing evidence linking high cholesterol and prostate cancer, and experts say cholesterol may also promote the growth of other tumors.
The newly published research is the first to find a direct link between high cholesterol and prostate cancer in humans, its authors claim. If confirmed, the findings would provide another important reason for keeping cholesterol levels under control with medication.
"Some laboratory studies suggest that [cholesterol-lowering] statin drugs help prevent prostate cancer, but the studies have been mixed," epidemiologist Christina Bosetti, PhD, tells WebMD. "We did not look at statins, but our results do indirectly suggest that they may help lower prostate cancer risk."
Self-Reported Survey
Bosetti and colleagues interviewed 1,294 Italian men with prostate cancer and 1,451 men with similar characteristics who did not have prostate cancer but were receiving medical treatment for other reasons. The interview included questions about medical history, covering roughly a dozen noncancerous conditions.
Prostate cancer patients in the study were roughly 50% more likely to report having had high cholesterol than men without the disease. The association was strongest for men with high cholesterol identified before age 50 and for men age 65 and over.
But no association was seen between prostate cancer and 10 other self-reported medical conditions, including diabetes, obesity, and high blood pressure.
Researcher Francesca Bravi says this apparent lack of association indicates that the link between prostate cancer and high cholesterol is real.
The study is published in the April 12 online edition of the journal Annals of Oncology.
Other Cancers
Male sex hormones, known as androgens, stimulate the growth of prostate cancer. Cholesterol is used by the body to make androgens and other steroid hormones.
The researchers say this association may explain how high cholesterol promotes the growth of prostate cancer. They add, however, that more research is needed to prove this.
Michael Freeman, PhD, has also studied cholesterol's impact on prostate cancer as director of urological diseases research at Children's Hospital Boston.
His own research in mice found that cholesterol in the bloodstream promoted the growth of existing prostate cancers but did not initiate the tumors. In test tube studies, Freeman and colleagues also found that prostate cancer cells stopped growing when exposed to a cholesterol-lowering statin drug.
Freeman tells WebMD that the sex hormone hypothesis is just one potential way in which cholesterol may promote prostate cancer. He says there is evidence that high circulating cholesterol levels promote the growth of many types of cancer, not just those that are fueled by sex hormones.
For this reason, controlling high cholesterol with medication may prove to be an important piece of the cancer prevention puzzle.
"The picture that is now emerging suggests that high circulating cholesterol levels can actually change the biochemical pathways that are operating in tumor cells," he tells WebMD. "The prostate may be an organ that is particularly susceptible to these cholesterol mechanisms, but it may not be the only one."
SOURCES: Bravi, F. Annals of Oncology, April 12, 2006; online edition. Cristina Bosetti, PhD, epidemiologist, Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy. Michael Freeman, PhD, program director, Urological Diseases Research Center, Children's Hospital, Boston.