Homogénéité de la distribution spatiale des cancers du système reproducteur féminin au Québec

Risk factors associated with women's reproductive life and sexual growth do not adequately predict cancer incidence of the breast, uterus and ovary. The heterogeneous worldwide distribution of these cancers could imply that some environmental and cultural risk factors are involved in their cancerogenesis. The few attempts made so far to unravel their spatial structures at a geographic scale facilitating the search for exogeneous risk factors have proved inconclusive. This study reports the results of a spatial analysis of the cancer incidence rates for breast, cervix, endometrium and ovary among Community Health Departments (CHD) in Quebec using a spatial autocorrelation method. Correlograms built according to four definitions of the inter-CHDs distance indicate that breast and ovary incidence rates follow quite similar spatial gradients attesting to their etiologic affinity. They also suggest that the spatial distribution of endometrial cancer follows a gradient divergent from that of breast and ovary cancers, and that the CHDs'spatial scale does not suitably describe the distribution of cervical cancer. The demonstration of a structured spatial distribution for breast, endometrium and ovary cancers in Québec strengthen the hypothesis that cultural or environmental risk factors are involved in their etiology. But, the observed disparities in the spatial structure of these cancers imply that their etiologic specificity may be greater than their biologic bond would suggest.