BNC Cancer

Roxana Moslehi*, Elizabeth Freedman, Nur Zeinomar, Carmela Veneroso and Paul H. Levine

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Background: To assess the importance of heredity in the etiology of inflammatory breast cancer (IBC), we compared IBC patients to several carefully chosen comparison groups with respect to the prevalence of first-degree family history of breast cancer.

Methods: IBC cases (n=141) were compared to non-inflammatory breast cancer cases (n=178) ascertained through George Washington University (GWU) with respect to the prevalence of first-degree family history of breast cancer and selected environmental/lifestyle risk factors for breast cancer. Similar comparisons were conducted with subjects from three case–control studies: breast cancer cases (n=1145) and unaffected controls (n=1142) from the Cancer Genetic Markers of Susceptibility (CGEMS) study, breast cancer cases (n=465) and controls (n=9317) from the Women’s Health Initiative (WHI) study, and ovarian cancer cases (n=260) and controls (n=331) from a study by University of Toronto (UT).

Results: The frequency of first-degree breast cancer family history among IBC cases was 17.0 % compared to 24.4 % for GWU breast cancer cases, 23.9 % and 17.9 % for CGEMS breast cancer cases and controls, respectively, 16.9 % and 12.6 % for WHI breast cancer cases and controls, respectively, and 24.2 % and 11.2 % for UT ovarian cancer cases and controls, respectively. IBC cases had a significantly lower prevalence of parous women than WHI breast cancer cases (OR=0.46, 95 % CI:0.27–0.81) and controls (OR = 0.31, 95 % CI:0.20–0.49). Oral contraceptive use was significantly higher among IBC cases compared to WHI breast cancer cases (OR=7.77, 95 % CI:4.82–12.59) and controls (OR=8.14, 95 % CI:5.28–12.61). IBC cases had a significantly higher frequency of regular alcohol consumption (≥1 drink per day) compared to WHI controls (OR=1.84, 95 % CI:1.20–2.82) and UT controls (OR=1.86, 95 % CI:1.07–3.22) and higher (statistically non-significant) prevalence (21.3 %) compared to breast cancer cases from GWU (18.2 %) and WHI (15.2 %).

Conclusions: The prevalence of first-degree breast cancer family history among IBC cases was lower compared to breast and ovarian cancer cases but higher than unaffected individuals. Our multiple-case inflammatory and non-inflammatory breast cancer families may reflect aggregation of common genetic and/or environmental factors predisposing to both types of breast cancer. Our findings that oral contraceptive use and regular alcohol consumption may be associated with IBC warrant further investigations.

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* Denotes CSDA Associates and Staff