abstract: Priorities for cancer prevention: lifestyle choices versus unavoidable exposures

Priorities for cancer prevention: lifestyle choices versus unavoidable exposures:
Source: The Lancet Oncology

"Although cancer prevention in the USA and other developed countries focuses on disease attributable to lifestyle factors such as smoking, alcohol intake, sun exposure, and obesity, cancer caused by involuntary exposures is a concern. The term environmental is ambiguously used to distinguish between lifestyle and unavoidable exposures. The general community is said to be vulnerable to carcinogens encountered in pollution, contaminated food, and consumer products. In view of these concerns, assessments of the carcinogenicity of particular chemicals are of little assistance in prevention of cancer. Appraisal of cancer attributable to widespread and localised pollution, pesticides, endocrine disrupting chemicals, and consumer products yields diverse outcomes, from established causation to absence of harm. The precautionary principle is not a practicable approach for unknown carcinogenic risks. Procedures for individuals to reduce exposure to recognised or suspect carcinogens in consumer products are not effective measures for cancer prevention. Anxiety concerning insidious cancer causation could divert attention from proven means of cancer prevention."

No Gene-Environment Interactions Found in Million Women Study of Breast Cancer 2010 - CA: A Cancer Journal for Clinicians - Wiley Online Library

".....Regarding the question of gene-environment interactions, lead author Ruth Travis, MD, PhD, adds that “Results from this study suggest that common genetic and environmental factors (reproductive and lifestyle factors) act independently on breast cancer risk, so regardless of common inherited genetic variation, a woman can still reduce her risk by modifying her lifestyle, for example by maintaining a healthy body weight and limiting alcohol intake.”

The absence of interactions means that priorities for risk-reducing strategies are similar for most women (for example, being based on known risks associated with lifestyle and reproductive factors) regardless of the common genetic risk factors for the disease, she says. Dr. Travis is an epidemiologist, research fellow, and senior scientist in the cancer epidemiology unit at Oxford University....."

JCO (Special Issue) Overview: Host Factors and Cancer Outcome

"A solitary focus on tumor-related factors may explain some of the
failures of clinical translations of preclinical discoveries, which often
take place in systems (eg, the cell culture) that do not involve host
influences. There is growing evidence that it is necessary to go beyond
the cell into the whole organism to fully understand the biology of
cancer and its treatment. In the clinic, we are constantly reminded that
the cancer cell does not exist in isolation in the controlled environment
that is possible in the laboratory—it exists within a complex host
that interacts with both the cancer cell and the treatments that are used
to target that cancer cell. It is our hope that this special issue of Journal
of Clinical Oncology will stimulate future basic and translational research
that will facilitate the incorporation of these complex tumor,
treatment, and host factor interactions to optimize the care provided
to our patients."

NCI Cancer Bulletin - Expert Panel Reports on Knowledge Gaps for 20 Suspected Carcinogens

In a monograph released July 15, a coalition of leading health organizations called for more research into the possible cancer-causing effects of exposure to 20 chemical agents. Some of the named agents are commonly found in the environment, whereas others are more often limited to occupational exposures. A summary paper in Environmental Health Perspectives provides an overview of the technical report.

The monograph, titled Identification of research needs to resolve the carcinogenicity of high-priority IARC carcinogens, summarizes available evidence and provides specific guidance on the appropriate studies needed to definitively classify these agents. Several overarching issues were identified that pertain to multiple agents, including recognizing that carcinogenic agents can act through multiple pathways and mechanisms of toxicity.

“This report highlights the importance of conducting research in occupational settings to identify human carcinogens,” said Dr. Debra Silverman, a co-author of the report and chief of the Occupational and Environmental Epidemiology Branch in NCI’s Division of Cancer Epidemiology and Genetics. “Findings from such occupational studies often allow experts to extrapolate the possible effects of low-level exposure to these agents in the general environment.”

“There is significant concern among the public about substances or exposures in the environment that may cause cancer, and there are some common occupational agents and exposure circumstances where evidence of carcinogenicity is substantial but not yet conclusive for humans,” added the report’s lead author, Dr. Elizabeth Ward, from the American Cancer Society (ACS).

The project originated as part of the National Institute for Occupational Safety and Health’s National Occupational Research Agenda to enhance occupational cancer research, and it involves collaboration with NCI, the International Agency for Research on Cancer (IARC), the ACS, and the National Institute of Environmental Health Sciences.