Environmental factors of cancer
INSERM EXAMINES THE RELATIONSHIP BETWEEN ENVIRONMENT AND CANCER.
The National Institute for Health and Medical Research (INSERM) publishes the results of a literature review on possible links between environment and development of certain cancers. Without giving any definitive answers about a complex subject, however, the study provides a number of lessons.
Sharp increase in cancer in 25 years, but declining mortality
The origin of the study is the observation that in 25 years; the incidence rate of cancer rose 35% in men and 43% among women, reaching about 320,000 new cases in 2005 ( 180,000 males and 140,000 females). This evolution was accompanied, however, during the same period, a continued decline in mortality from cancers, thanks to advances in screening and treatment. This decline in mortality even accelerated over the last five years.
The study by Inserm on the issue was commissioned by the French Agency of Health Safety Environment and Labour (Afsset). This review of the literature on the subject is based on a documentary basis of nearly 1800 items available in the first half of 2007. Conducted by two research groups with expertise in the fields of epidemiology, toxicology, clinical, the occupational health and risk quantification, it covers nine types of cancer: lung cancer, mesotheliomas, hematologic neoplasms, brain tumors, breast, ovarian, testicular, prostate and thyroid. These locations correspond to cancers whose incidence has increased over the last twenty years and for which a link with environmental factors may be suspected.
Each of the nine cancers studied the subject of detailed analysis that strives, from the available scientific literature, to answer a series of questions: what are the incidence data and their changes (according to regions) and in other countries? What are the environmental risk factors in the workplace or general identified as carcinogens or debated? What are the available epidemiological data on these factors? ... Other issues are discussed in section, like those of the main mechanisms of toxicity, mode of action of certain pollutants or different ways to quantify exposure to environmental agents.
From the analysis of these issues, the study indicates the best sources of information on exposures and their evolutionary trends in recent decades. An implication is that the link between cancer and environmental factors must still be studied. The study makes finally for each of the cancers studied, a number of recommendations.