Perineal talc use and ovarian cancer risk: a case study of scientific standards in environmental epidemiology.

A number of observational studies (largely case-control) conducted over the last two decades suggest an association between use of talc powders on the female perineum and increased risk of ovarian cancer. A subset of these reports shows a roughly 30-60% increased risk of ovarian cancer associated with perineal talc exposure. A number of researchers partly base their conclusions of an association on the '…chemical relationship between talc and asbestos', the latter substance being a known human carcinogen.

Maternal intake of N-nitroso compounds from cured meat and the risk of pediatric brain tumors: a review.

Experimental investigations conducted over the last several decades suggest that transplacental exposure of offspring to certain N-nitroso compounds (NOCs) results in the development of brain tumors in laboratory animals. Dietary cured meats are a recognized source of such exposures in humans, which raises the possibility that maternal consumption of cured meat products during pregnancy could increase the risk of childhood brain tumors. This hypothesis was first suggested by an observational study conducted by Preston-Martin et al.

Evidence-based criteria in the nutritional context.

During the last decade, approaches to evidence-based medicine, with its heavy reliance on the randomized clinical trial (RCT), have been adapted to nutrition science and policy. However, there are distinct differences between the evidence that can be obtained for the testing of drugs using RCTs and those needed for the development of nutrient requirements or dietary guidelines. Although RCTs present one approach toward understanding the efficacy of nutrient interventions, the innate complexities of nutrient actions and interactions cannot always be adequately addressed through any single research design.

Smoking as a risk factor for prostate cancer: a meta-analysis of 24 prospective cohort studies.

Objectives: We evaluated the relationship between smoking and adenocarcinoma of the prostate.

Methods: We pooled data from 24 cohort studies enrolling 21 579 prostate cancer case participants for a general variance-based meta-analysis. Summary relative risks (RRs) and 95% confidence intervals (CIs) were calculated separately for mortality and incidence studies.

Colorectal cancer risk and dietary intake of calcium, vitamin D, and dairy products: a meta-analysis of 26,335 cases from 60 observational studies.

In vivo and in vitro studies suggest that dairy products, calcium, and dietary vitamin D inhibits the development of colorectal cancer (CRC). A meta-analysis was performed to evaluate this relationship in observational studies. Data from 60 epidemiological studies enrolling 26,335 CRC cases were pooled using a general variance-based meta-analytic method.

Dairy products, dietary calcium and vitamin D intake as risk factors for prostate cancer: a meta-analysis of 26,769 cases from 45 observational studies.

In this study, we examined the available evidence and sources of heterogeneity for studies of dairy products, calcium, and vitamin D intake and the risk of prostate cancer. We pooled data from 45 observational studies using a general variance-based, meta-analytic method employing CIs. Summary relative risks (RRs) were calculated for specific dairy products such as milk and dairy micronutrients.

Impact of dairy products and dietary calcium on bone-mineral content in children: results of a meta-analysis.

Objective: Although calcium is essential for maintaining bone health in children, the optimum dietary intake of calcium in this age group, particularly in the form of dairy foods, is not well defined. A meta-analysis was conducted to examine the impact of dietary calcium/dairy supplementation on bone mineral content in this age group.

Methods: Data were pooled from randomized controlled intervention trials and observational studies using previously described methods.

Perineal talc use and ovarian cancer: a critical review.

Talc, like asbestos, is a silicate that has been studied in relation to cancer risk. Several studies conducted over the past 25 years found an association between perineal talc powders and ovarian cancer. The summary relative risk is about 1.

Use of cosmetic talc on contraceptive diaphragms and risk of ovarian cancer: a meta-analysis of nine observational studies.

Prior work suggests an association between perineal use of cosmetic talc and increased ovarian cancer risk. A meta-analysis was performed to examine this hypothesis by evaluating ovarian cancer risk associated with direct exposure of the female genital tract to talc via dusting of contraceptive diaphragms. Data were pooled from epidemiological studies using a general variance-based meta-analytic method that employs confidence intervals.

Personal use of hair dyes and the risk of bladder cancer: results of a meta-analysis.

Objective: This study examined the methodology of observational studies that explored an association between personal use of hair dye products and the risk of bladder cancer.

Methods: Data were pooled from epidemiological studies using a general variance-based meta-analytic method that employed confidence intervals. The outcome of interest was a summary relative risk (RRs) reflecting the risk of bladder cancer development associated with use of hair dye products vs.

The influence of intravesical therapy on progression of superficial transitional cell carcinoma of the bladder: a metaanalytic comparison of chemotherapy versus bacilli Calmette-Guerin immunotherapy.

Objective: Currently, the true impact of intravesical chemotherapy or immunotherapy (bacilli Calmette-Guerin [BCG]) on the rate of progression of superficial transitional cell carcinoma of the bladder to muscle invasive disease is unclear. A metaanalysis was performed to statistically compare the efficacy of these treatments in preventing tumor progression in this disease setting.

Methods: A prospective protocol outlining the metaanalysis noted here was developed followed by a thorough search of the existing published literature using strict eligibility criteria.

A meta-analysis of the timing of chest irradiation in the combined modality treatment of limited-stage small cell lung cancer.

The objective of this study was to determine whether initial combined chemoradiation results in superior 1-, 2-, and 3-year survivals in the treatment of limited-stage small cell lung cancer versus sequential or split-course therapy. Using a prospective meta-analysis protocol outlining study inclusion criteria, literature search strategy, and statistical procedures, data from all available randomized controlled trials addressing the above-noted objective were pooled using a fixed effects model (Peto). Results were expressed as summary odds ratios (ORp), and statistical tests for data heterogeneity were performed prior to calculation of ORps.

Presentation of malignant pleural mesothelioma with symptomatic brain metastasis: report of a case.

Central nervous system metastases from diffuse malignant pleural mesothelioma are rare. Here we describe a patient without known asbestos exposure who presented with chest pain, increasing shortness of breath and persistent headache. Evaluation found biphasic malignant mesothelioma of the right hemithorax and a single brain metastasis confirmed by computed tomography.

A meta-analysis of maternal cured meat consumption during pregnancy and the risk of childhood brain tumors.

Objective: N-Nitroso compounds (NOCs) are recognized neural carcinogens in animal models and are suspected human carcinogens. A meta-analysis was performed examining the possible association of maternal intake of cured meat (an important source of dietary NOCs) during pregnancy and the risk of pediatric brain tumors.

Methods: Data from epidemiological studies were pooled using a general variance-based meta-analytic method employing confidence intervals described by Greenland in 1986.

Dietary cured meat and the risk of adult glioma: a meta-analysis of nine observational studies.

Objective: N-nitroso compounds (NOCs) are recognized neural carcinogens in animal models and are suspected human carcinogens. A meta-analysis was performed examining the possible association of dietary N-nitroso intake from cured meats and the risk of gliomas in adults.

Methods: A prospective protocol was developed outlining the intent, methods, and statistical analysis of the meta-analysis.

Impact of intravesical chemotherapy versus BCG immunotherapy on recurrence of superficial transitional cell carcinoma of the bladder: metaanalytic reevaluation.

Bacille Calmette-Guérin (BCG) immunotherapy is currently considered the most effective agent in the management of superficial bladder cancer. Prior work suggests that the efficacy of intravesical chemotherapy in preventing tumor recurrence may be greater than previously suggested. This latter finding, therefore, brings into question the currently perceived superiority of BCG treatment for this disease.

Chemoembolization of hepatocellular carcinoma: results of a metaanalysis.

Transcatheter arterial chemoembolization is considered the mainstay of therapy for unresectable hepatocellular carcinoma. The purpose of this study was to assess the impact of such treatment on survival by performing a metaanalysis of all available randomized clinical trials comparing this form of therapy to supportive care. A MEDLARS search was conducted covering the years 1970 to 2002.

Perineal application of cosmetic talc and risk of invasive epithelial ovarian cancer: a meta-analysis of 11,933 subjects from sixteen observational studies.

Objective: Prior epidemiological studies suggest an association between perineal cosmetic talc use and increased risk of epithelial ovarian cancer. A meta-analysis was performed to evaluate this suspected association.

Materials And Methods: Using previously described methods, a protocol was developed for a meta-analysis examining the association between perineal talc use versus non-use and the development of invasive epithelial ovarian cancer.

Metastatic breast carcinoma presenting as a large pulmonary embolus: case report and review of the literature.

Involvement of the pulmonary vasculature by carcinoma of the breast typically occurs in the form of microscopic tumor emboli involving the small arteries, arterioles, or capillaries. Obstruction of a large pulmonary artery by a tumor embolus has not been reported. We describe a patient with a history of breast carcinoma diagnosed 5 years previously who sought treatment for dyspnea and a large mass in the right pulmonary artery suggestive of a pulmonary embolus.

Maternal smoking during pregnancy and the risk of childhood brain tumors: a meta-analysis of 6566 subjects from twelve epidemiological studies.

Objective: Prior epidemiological studies suggest a possible association between maternal smoking during pregnancy and risk of childhood brain tumors. A meta-analysis was performed statistically pooling all available observational studies on this topic in order to evaluate this suspected association.

Methods: Using previously described methods, a protocol was developed for a meta-analysis examining the association between maternal smoking during pregnancy and subsequent development of primary brain tumors in their offspring.

Use of topical sunscreens and the risk of malignant melanoma: a meta-analysis of 9067 patients from 11 case-control studies.

Objectives: This study examined the methodology of epidemiological studies that suggest use of topical sunscreen preparations is associated with increased risk of malignant melanoma.

Methods: We pooled data from observational studies using a general variance-based meta-analytic method that employed confidence intervals (previously described). The outcome of interest was a summary relative risk (RR) reflecting the risk of melanoma associated with sunscreen use versus nonuse.

Combined chemoradiation versus radiation therapy alone in locally advanced nasopharyngeal carcinoma: results of a meta-analysis of 1,528 patients from six randomized trials.

It is currently unclear whether the addition of chemotherapy to standard radiation therapy improves clinical outcome in patients with locoregionally advanced nasopharyngeal cancer. A meta-analysis was performed to evaluate the impact of integrating chemotherapy with external beam radiation therapy in this clinical setting. Using previously described methods, a protocol was developed outlining a meta-analysis examining the influence of chemoradiation versus radiation alone (control arm) in locoregionally advanced nasopharyngeal carcinoma.

Non-asbestos related diffuse malignant mesothelioma.

Aims: The association between asbestos exposure and the development of malignant mesothelioma is well known. Nonetheless, a proportion of patients suffering from this disease do not appear to have documented exposure to asbestos fibers from any known source. Available information suggests that a true "background" incidence of this disease exits raising the possibility that other factors contribute to its etiology.