Evaluating the incidence of inflammatory breast cancer using population- and hospital-based cancer registries in Casablanca, Morocco.

Background: Inflammatory breast cancer (IBC) is a rare and aggressive type of breast cancer (BC). Physicians have difficulty diagnosing it correctly given its clinical nature. Previous studies have shown that North Africa compared to the United States has a higher proportion of IBC relative to all BC.

Purpose: The purpose of this study was to calculate a corrected IBC incidence rate using the population-based registry of Casablanca and other, local hospital-based data sources and to characterize the clinical presentation and basis of diagnosis of IBC.

Methods: We retrieved the Casablanca registry data from 2009-2012, and matched its data with demographic and clinical data from the medical records, logbooks and a local epidemiologic IBC case-control study. A corrected incidence was calculated after accounting for missed cases in the registry.

Results: The data showed that the incidence of IBC in the registry was significantly underestimated when the population-based and hospital data were combined.

Conclusions: Population-based registries should focus on specific measures for verifying the diagnosis of IBC since physicians may miss documenting the disease in medical records. This study may have implications for better reporting and documentation of IBC in hospital- and population-based cancer registries in Morocco and other similar countries.