US Pharm. 2007;32(6):28.

Regular Aspirin Use Reduces Risk of Colon Cancer
Taking at least two 325-mg tablets weekly for an extended period cuts the risk of colorectal cancers by almost one third, but only in tumors overexpressing cyclooxygenase-2 (COX–2), according to a study published in the New England Journal of Medicine. Andrew T. Chan, MD, of HarvardMedicalSchool and colleagues reported a reduced risk for COX-2–positive tumors becoming evident after 10 years of aspirin use, suggesting an effect on early stages of cancer.

In an accompanying editorial, Sanford D. Markowitz, MD, PhD, of CaseWestern ReserveUniversity in Cleveland, wrote that current thinking ascribes the cancer-preventive activity of aspirin and NSAIDs principally to the ability of COX-2 to block the generation of PGE2, the most abundant colon prostaglandin. The findings of this study "provide powerful support for the role of COX-2 as a key mediator in the development of colon cancer and now pose questions about the clinical implications of discovering differences between colon cancers that express high or low levels of COX-2," said Dr. Markowitz.

Mega Multivitamin Use Linked to Prostate Cancer
Men taking multivitamin supplements more than once a day are twice as likely to die of prostate cancer as men who never take supplements, according to a report in the Journal of the National Cancer Institute. The prospective study included 295,344 men ages 50 to 71 who were free of cancer at enrollment in 1995 and 1996.

The researchers reported elevated risk and incidence rates of both advanced and fatal disease, with associations strongest in men with a family history of prostate cancer or in those who consumed selenium, beta-carotene, or zinc. Among men with a family history, heavy multivitamin use (more than seven times per week) more than doubled the risk for advanced prostate cancer. Researchers concluded that the possibility of an associated risk "is of concern and merits further evaluation."

Protease Inhibitors Tied to Increased Heart Attack
Treating HIV with protease inhibitors (PIs) is associated with an increased risk of heart attack, according to results from a large observational study of 23,437 HIV-infected patients published in the New England Journal of Medicine. Researchers reported a 16% risk increase per year, which amounts to about a doubling of the risk of myocardial infarction over five years. The incidence in patients receiving PIs for more than six years was only .6% per year, which is considered "low or at most moderate, depending on a patient's risk-factor burden," said James Stein, MD, of the University of Wisconsin. There was no association found between heart attack and the use of nonnucleoside reverse transcriptase inhibitors.

"There does not appear to be an epidemic on the horizon--simply a risk that needs to be managed--perhaps by targeting the modifiable risk factors associated with heart disease, rather than the lipid effects of antiretroviral therapy," said Dr. Stein.

Statins May Decrease Lung Cancer Risk
Use of a statin for at least six months was associated with a 55% reduced risk of lung cancer, according to results of a retrospective study published in Chest. The case-control study of 483,733 patients (primarily men) used data prospectively collected from 1998 through 2004, representing the first large, population-based study of statins and lung cancer.

"Our study suggests that statins have a potential role in primary chemoprevention for lung cancer, yet randomized, prospective, double-blind, placebo-controlled clinical trials are necessary to validate the value of statins in lung cancer prevention and treatment," concluded Vikas Khurana, MD, of Louisiana State University Health Sciences Center. At present, statin use should be based on Adult Treatment Panel III guidelines pending further data on lung cancer incidence and mortality.

Antidepressants May Double the Risk of  Bone Fractures
Regular use of selective serotonin reuptake inhibitors in patients ages 50 and over is associated with double the rate of fractures as those not using such medications, according to a report in the newsletter Harvard Women's Health Watch. While further studies into this link are required, bone density tests and adequate calcium intake may benefit this population.

--Kanika Sahdev, PharmD

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