Association of Metformin With the Growth of Vestibular Schwannomas.

OBJECTIVE: To assess whether medication use, specifically statin, metformin, and aspirin, affects the growth of vestibular schwannomas (VSs). STUDY DESIGN: Retrospective case series. SETTING: Single tertiary care academic hospital. SUBJECTS AND METHODS: Patients were enrolled if they were diagnosed with sporadic VS and had at least 2 magnetic resonance imaging (MRI) studies at a minimum of 6 months apart prior to any intervention. Electronic medical records were reviewed for demographic and medication data. Tumor volumes on MRI studies were assessed via BrainLab iPlan. The primary endpoint was VS tumor growth, defined as a 20% increase in tumor volume, between consecutive MRI studies or between the first and last available MRI study. Predictors of volumetric growth, specifically statin, aspirin, or metformin use, were analyzed with t tests, chi-square test, univariate logistic regression, and multivariate logistic regression. RESULTS: A total of 387 patients met inclusion criteria, 53.5% of whom were women. For all patients, the mean age was 60.6 years (range, 18.2-89.2 years); the mean axial tumor diameter, 11.9 mm (range, 1.7-32.0 mm); and the mean tumor volume, 0.85 cm3 (range, 0.01-13.1 cm3). In review of the electronic medical record, 46 patients (11.9%) were taking metformin; 145 (37.5%), a statin; and 117 (30.2%), aspirin. Among patients taking metformin, 39.1% (18/46) exhibited volumetric growth, as opposed to 58.2% (198/340) of nonusers (P = .014). Metformin (odds ratio, 0.497; P = .036) is significantly associated with reduced VS growth when controlling for aspirin, statin, and tumor size on multivariate logistic regression. CONCLUSION: Metformin use is associated with reduced volumetric VS growth.

Epidemiological evidence relating snus to health--an updated review based on recent publications.

An earlier review summarized evidence relating use of snus (Swedish-type moist snuff) to health and to initiation and cessation of smoking. This update considers the effect recent publications on snus use and health have on the overall evidence. The additional evidence extends the list of neoplastic conditions unassociated with snus use (oropharynx, oesophagus, stomach, lung) to include colorectal cancer and acoustic neuroma, and further undermines the weakly-based argument that snus use increases the risk of pancreatic cancer, although there is a report of poorer cancer survival in users. It remains undemonstrated that "snuff-dipper's lesion" increases risk of oral cancer, and recent publications add to the evidence that snus use has no effect on periodontitis or dental caries. Although onset of acute myocardial infarction is not adversely associated with snus use, there is some evidence of an association with reduced survival. Whether this is a direct effect of snus use or a result of confounding by socioeconomic status or other factors requires further investigation, as does a report of an increased risk of heart failure in snus users. Even if some adverse health effects of snus use do exist, it remains clear that they are far less than those of smoking.

Tumor induction by a single subcutaneous injection of 1-butyl-1-nitrosourea or 1-butylurea in newborn mice.

A subcutaneous injection of 1-butyl-1-nitrosourea (BNU) at the maximum tolerated dose (333 mg/kg body wt.) to newborn CDF1 mice induced adenocarcinoma and adenoma of the lung, adenoma of the liver, thymic or non-thymic lymphoma and neurinoma of the acusticus nerve; the total incidence of tumors was statistically significant as compared with that of control. However, in the 1-butylurea (BU) mice, one adenoma of the lung was induced in a male mouse; the total incidence of tumor was comparable to that of control.