Apparent Decline in Inflammatory Breast Cancer Incidence in Tunisia Associated with Improved Socioeconomic Conditions.

Abstract

Abstract Aim: Numerous publications since the 1970s have reported an apparently high frequency of IBC in Tunisia affecting up to 50% of breast cancer patients. In the past 20 years, 3 complete national population-based cancer registries have provided more precise information about breast cancer (BC) incidence. Moreover, IBC diagnostic criteria moved from the French classification of aggressive or rapidly progressing breast cancer (RPBC) also designated as "pousee evolutive" (PEV) to the current system of the American Joint Committee on Cancer (AJCC). In this study we reviewed a series of publications and recent data from the Tunisian Breast Cancer Registries to evaluate the gradual changes in IBC and non-IBC and relate the findings to improvements in the general economic situation in this country.Methods: All indexed Tunisian publications regarding RPBC and IBC since 1970 were compiled and their data were compared to recent data from the Tunisian Cancer Registries. These findings were compared to reports on changing breast cancer patterns in Tunisia overall.Results: Trends in Tunisian BC were compared to the original report of RPBC from Tunisia's National Cancer Institute, the Institut Salah Azaiz, which noted 340 of 581 (58.5%) consecutive breast cancer patients had RPBC which included 282 (48.5%) PEV 3 patients clinically indistinguishable from IBC in the United States. In 6 subsequent series including 700 to 1400 patients affected by BC published from 1985 to 2008, the relative percentage of IBC patients gradually decreased to 30.3%, 6.2% and 5.7% associated with a concurrent increase in the incidence of breast cancer nationwide. Registry data and hospital-based studies have shown also a progressive decrease in mean clinical tumor size in the past four decades from 60mm to 40mm and a discordant tumor size between private patients and public patients, the latter having significantly larger tumors at diagnosis. This trend, compatible with the early observation of a rural predominance of RPBC and a gradual increase in gross national product supports other etiuologic studies indicating a strong environmental determinant. for IBC.Conclusion: These data support a number of studies indicating that environmental factors, including poorer socioeconomic conditions, prolonged breast feeding, and obesity may be risk factors for IBC, and indicate the importance of environmental factors in the etiology of this disease. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2077.