Abstract P6-14-08: Risk factors for developing inflammatory breast cancer: Unique trends among a single patient population
Authors: White Randie E , Warren Laura E , Bellon Jennifer R , Nakhlis Faina , Jacene Heather A , Yeh Eren D , Hirshfield-Bartek Judith , Overmoyer Beth ,   Inflammatory Breast Cancer International Consortium
Published: May 2015

Introduction: Inflammatory breast cancer (IBC) is a virulent form of breast cancer, characterized by skin erythema and edema associated with enlargement of the breast rapidly occurring within 3-6 months (mo). Because of its rarity (&lt;5% incidence), there is a paucity of data identifying epidemiologic risk factors, which may shed light on the potential causes of IBC, and guide prevention strategies.

Methods: This study utilized retrospective data obtained from an IRB approved database of 275 patients (pts) with IBC evaluated at Dana Farber Cancer Institute (DFCI) from 1997-2012. Pts with confirmed invasive breast cancer had documented clinical characteristics of IBC clinically staged as T4d. The statistical software JMP 10 was used to perform statistical tests. Chi Square Tests, Fisher’s Exact Tests, and descriptive statistics were compiled.

Results: The mean age of diagnosis among our study population was 50.2 years (yrs). IBC pts were more frequently diagnosed when premenopausal (55%) versus (v) postmenopausal (45%); 25% of pts had metastases upon presentation. The majority of patients (77%) were overweight (BMI 25-29.9) or obese (BMI≥30). More premenopausal pts (80.3%) had a BMI &gt;25 v postmenopausal pts (73.5%). We observed no association with BRCA status among those undergoing genetic testing (13% BRCA positive (pos); 54 tested); however 52% of pts had a family history of breast cancer (5% BRCA pos). The majority of pts (81%) did not undergo genetic testing. The most common IBC subtype was HER2 pos (40%); 19% were triple negative (neg), and 16% were hormone receptor (HR) pos/HER2 neg. We also observed a trend of a longer duration of symptoms prior to diagnosis among younger pts. The mean age of pts who experienced &gt;6 months (mo) of symptoms prior to diagnosis was 42 yrs v the mean age of 51 yrs among those experiencing &lt; 2 mo of symptoms prior to diagnosis. Pts also displayed a temporal trend in diagnosis dependent upon time of year. 57% of pts were diagnosed with IBC during the warmer temperatures (Mar 21 – Sept 20) compared with 43% diagnosed during the cooler temperatures (Sept 21– Mar 20).

Conclusion: This retrospective epidemiologic analysis demonstrated various trends in a single population of IBC pts. The association of high BMI and risk of developing IBC among premenopausal women contrasts with that seen in the non-IBC group, i.e. high BMI is a risk factor for non-IBC only among postmenopausal women. Targeting the obesity crisis may be a means of reducing the risk of developing IBC among younger women. A differentiating feature of IBC is the rapid onset of signs and symptoms of IBC, and yet, younger pts had a significant delay in diagnosis of &gt;6 mo compared with older pts. This emphasizes the urgency to educate both pts and providers about IBC and facilitate rapid diagnostic procedures. The seasonal relationship with diagnosis observed in this cohort of IBC pts is intriguing. Investigators have hypothesized an infectious etiology contributing to the development of IBC, namely infection by viruses or bacterial pathogens may play a role in the pathophysiology of IBC. These unique trends seen in the DFCI IBC population deserve further investigation.

Citation Format: Randie E White, Laura E Warren, Jennifer R Bellon, Faina Nakhlis, Heather A Jacene, Eren D Yeh, Judith Hirshfield-Bartek, Beth Overmoyer, Inflammatory Breast Cancer International Consortium. Risk factors for developing inflammatory breast cancer: Unique trends among a single patient population [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-14-08.