Descriptive Studies[unreadable] Evaluation of demographic, temporal, and geographic variation in cancer rates may suggest clues to the roles of environmental or cultural influences; identification of population subgroups or regions at notably high or low risk may indicate areas where more intensive studies might be particularly fruitful. The Atlas of Cancer Mortality in the United States, 1950-94 was published in 1999, and the online version is available at http://www.nci.nih.gov/atlasplus. Users can create customized maps and have flexibility in choice of cancers, age groups, and sex and race aggregation. The intranet has been updated to include data through 1999, and many county and SEA maps have been generated. We have been analyzing changes in the geographic patterns of mortality for those cancers with substantial variation by area, race, and/or gender. The geographic patterns for breast cancer mortality have remained remarkably static, but are more pronounced for women older than age 50 years than for younger women. Race- and age-specific breast cancer mortality rates from 1950 through 1999 were calculated for four census regions and 508 state economic areas of the United States. We found that although rates of breast cancer still tend to be highest in the Northeast, intermediate in the West and Midwest, and lowest in the South, the underlying mortality trends suggest somewhat slower recent dissemination of effective breast cancer treatment in the South. An analysis of mortality trends for cervical squamous and adenocarcinoma in the United States found that increases in carcinoma in situ seemed disproportionately large compared with improvements in mortality rates for squamous carcinoma and that despite increased reporting of adenocarcinoma in situ, declines in mortality for cervical adenocarcinoma have not been demonstrated conclusively. From our collaborators in Beijing, China, we received and are analyzing mortality data for the full 27 provinces for the two time periods 1973-75 and 1990-92. In contrast to mortality data, which are limited to specifying the form of cancer, incidence data include information on histologic type of the tumor and in many instances, the subsite of origin. We have used incidence data from the Surveillance, Epidemiology, and End Results (SEER) program to investigate further the demographic patterns to discern subgroups that may be of etiologic significance. We compared the incidence patterns for breast carcinoma in situ and invasive breast carcinoma according to estrogen receptor status. During the years 1973 to 2000, carcinomas in situ rates rose 660% and invasive carcinoma rates rose 36%, with the most rapid increase occurring in women age !Y50 years. The age-specific incidence patterns suggested that carcinogenic events operating early in reproductive life had greater impact upon carcinoma in situ and invasive carcinoma defined by estrogen receptor negative expression than upon invasive carcinoma defined by estrogen receptor positive expression. An analysis of breast carcinoma incidence among men found that rates have remained essentially stable for decades whereas those for females have increased worldwide. We identified distinct breast cancer incidence and prognostic patterns among high-risk and low-risk breast cancers, suggesting a possible link between etiology and outcome. Inflammatory breast carcinoma appears to be a clinicopathologic entity distinct from noninflammatory locally advanced breast cancer, and incidence rose throughout the 1990s while survival improved modestly; substantial racial differences were noted in age at diagnosis, age-specific incidence rates, and survival outcomes.