BOSTON -- Intense lipid-lowering may raise the threat of cancer as it reduces the risk of cardiovascular disease, according to results of a large meta-analysis.
BOSTON, July 24 -- Intense lipid-lowering may raise the threat of cancer as it reduces the risk of cardiovascular disease, according to results of a large meta-analysis.
The analysis of more than 300,000 person-years of follow-up revealed a statistically significant (P=0.009) inverse association between the achieved level of LDLs and cancer risk, Richard H. Karas, M.D., of Tufts-New England Medical Center, and colleagues, reported in the online version of the July 31 issue of the Journal of the American College of Cardiology.
In contrast the analysis showed no association between statin therapy and elevated liver enzymes or rhabdomyolysis, the primary objective of the study.
The authors emphasized that the cancer-LDL findings do not demonstrate a causal relationship. Nonetheless, the cancer association is disturbing and requires further investigation, they said. The study did not identify the forms of cancer with an elevated risk.
Dr. Karas and colleagues conducted a literature review to identify prospective, randomized clinical trials of statin therapy published through late 2005. The review identified 23 statin treatment arms comprising 75,317 patients and a cumulative follow-up of 309,506 person-years.
In their primary analysis, the investigators found no evidence of an association between elevated liver enzymes or rhabdomyolysis and the percent LDL lowering, absolute LDL reduction, or achieved LDL values. However, a statistically significant, positive and graded relationship emerged from an analysis of liver-enzyme elevation by statin dose.
The rate of liver-enzyme elevation with each 10% reduction in LDL was 271 per 100,000 person-years with high-dose statin therapy, 195/100,000 person-years with the intermediate dose, and 114/100,000 person-years with low-dose therapy (P<0.001 for all pair-wise comparisons).
The analysis of LDL lowering and cancer risk emerged from 13 statin treatment arms. The analysis revealed no association between cancer risk and the percent LDL reduction or the absolute reduction in LDL. Statin dose also had a small but statistically significant effect on cancer risk, leaving achieved LDL level with the only clear-cut association with cancer risk.
The authors emphasized that "the robust evidence demonstrating the efficacy in cardiovascular protection is not undermined by the present analysis and remains the basis for current guidelines and clinical practice." They also pointed out that all but one major statin trial (PROSPER, Prospective Study of Pravastatin in the Elderly at Risk) showed no association between statin therapy and cancer risk.