Since 1993, fewer and fewer American men have been dying of prostate cancer. Why?
An obvious reason is that during this time, more men have undergone prostate cancer screening with the PSA blood test. PSA (prostate-specific antigen) levels can rise sharply as prostate cancers begin to grow. But noncancer conditions, such as an enlarged prostate, can also make PSA levels go up.
Screening is indeed linked to the decline in prostate cancer deaths -- at least for white men, find Jared Cox, MD, and colleagues at the University of Alabama in Birmingham. And for black Americans, health insurance coverage is linked to fewer prostate cancer deaths.
But there's another explanation besides PSA screening. Cox and colleagues also find that men with higher cholesterol levels have a lower risk of prostate cancer. Men with high cholesterol usually get treated with cholesterol-lowering statin drugs.
In the test tube, statin drugs keep prostate cancer cells from growing. It's possible, Cox and colleagues suggested at this week's meeting of the American Urological Association (AUA), that the drugs could be protecting men against prostate cancer.
That's exactly what two other research groups reported at the AUA meeting.
Statins vs. Prostate Cancer
Robert J. Hamilton, MD, MPH, and colleagues at Duke and Johns Hopkins universities studied more than 1,500 men treated with statins at the Durham, N.C., VA Medical Center. None of the men had any sign of prostate cancer at the beginning of the study, but all of them were undergoing regular PSA screening tests.
After starting statin treatment, the men averaged a 31% drop in cholesterol levels. They also had a slight drop in PSA levels.
As it turned out, the greater the men's cholesterol decrease, the more their PSA levels dropped.
"Statins may influence prostate biology," Hamilton and colleagues suggest.
Taking a different approach, Teemu J. Murtola, MD, and colleagues at the University of Tampere, Finland, analyzed data from a study of 22,536 men aged 55 to 67. These men underwent PSA screening as part of a clinical trial.
Six years later, 4.7% of men who did not take statin drugs had developed prostate cancer. Among the more than 5,000 men who regularly took statin drugs, only 2.8% developed prostate cancer.
"Prostate cancer incidence was decreased among statin users, suggesting a chemopreventive effect," Murtola and colleagues suggest.