Prognostic Value of Body Mass Index in Locally Advanced Breast Cancer Shaheenah Dawood, 1,3 Kristine Broglio, 2 Ana M. Gonzalez-Angulo, 1 Shu-Wan Kau, 1 Rabiul Islam, 1 Gabriel N. Hortobagyi, 1 and Massimo Cristofanilli 1 Abstract Purpose: The purpose of this retrospective study was to determine the association and prognostic value of body mass index (BMI) at the time of initial diagnosis in patients with locally advanced breast cancer (LABC). The analysis includes the subsets of inflammatory (IBC) and noninflammatory (non-IBC LABC) breast cancer. Experimental Design: We identified 602 patients who had LABC treated on prospective clinical trials. BMI was divided into three groups: ( a) V24.9 (normal/underweight), ( b) 25.0 to 29.9 (overweight), and ( c) z30 (obese). Kaplan-Meier product limit method was used to estimate survival outcomes. Cox proportional hazards were used to determine associations between survival and BMI and to test for an interaction between BMI and breast cancer type. Results: Eighty-two percent had non-IBCLABC and18% had IBC. Obese patients tended to have a higher incidence of IBC compared with overweight and normal/underweight groups (P = 0.01). Median follow up was 6 years for all patients. Median overall survival (OS) and recurrence-free survival (RFS) were 8.8 and 5.9 years, respectively. Patients with LABC who were obese or over- weight had a significantly worse OS and RFS ( P = 0.001) and a higher incidence of visceral recur- rence compared with normal/underweight patients. In a multivariable model, BMI remained significantly associated with both OS and RFS for the entire cohort. The interactions between BMI and LABC subsets and between BMI and menopausal status were not statistically significant. Conclusion: Patients with LABC and high BMI have a worse prognosis. Evaluation of the biological factors associated with this observation can provide tools for additional therapeutic interventions. Locally advanced breast cancer (LABC) is an important public health problem, representing f5% of newly diagnosed breast cancers among women enrolled in periodic screening programs and up to 50% of women in medically underserved regions of the United States and many developing countries (1). 4 Inflammatory breast cancer (IBC), an aggressive and highly lethal form of breast cancer, represents a distinct subset of LABC that constitutes f1% to 6% of breast cancers diagnosed in the United States (2). A number of factors including tumor size, number of involved lymph nodes, estrogen receptor status, nuclear grade, and human epidermal growth factor receptor-2 status are known to influence prognosis of breast cancer (3, 4). A growing body of evidence suggests that body weight is also strongly associated with increasing risk of developing breast cancer (5, 6). Furthermore, patients with higher body mass index (BMI) have been found to have worse outcome (7, 8) and a higher risk of recurrence regardless of age or menopausal status (9, 10). In addition, women with higher fat content tend to have larger tumors and more involved lymph nodes at presentation (11, 12). Earlier studies have shown that high BMI was associated not only with a higher risk of developing IBC (13) but also with shorter survival (14). At the University of Texas M. D. Anderson Cancer Center, we have treated patients with locally advanced breast cancer in clinical trials using similar multimodality therapies (15, 16). The uniformity of treatments and follow-up procedures gives us the opportunity to evaluate the effect of biological factors with minimal confounding bias of other variables. We therefore decided to perform a retrospective study to determine the association and prognostic value of BMI in LABC and to determine if the effect of BMI was different between the non-IBC LABC and IBC subgroups. Patients and Methods Patient population. Women with breast cancer treated according to clinical protocols, conducted in the Breast Medical Oncology Department 4 https://web.facs.org/ncdbr/help_compare6/ver6_site_stage_2001.htm Imaging, Diagnosis, Prognosis Authors’ Affiliations: 1 Department of Breast Medical Oncology and 2 Division of Quantitative Sciences, The University of Texas M. D. Anderson Cancer Center, Houston, Texas and 3 Medical Oncology, Department of Health and Medical Services, Dubai Hospital, Dubai, United Arab Emirates Received 6/15/07; revised 8/31/07; accepted 1/3/08. Grant support: Susan G. Komen Foundation, the Nellie B. Connally Fund for Breast Cancer Research, and the Inflammatory Breast Cancer Research Group. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. Note: Presented in part at American Association for Cancer Research Annual Meeting 2007, April 14-18, Los Angeles, CA. Requests for reprints: Massimo Cristofanilli, Department of Breast Medical Oncology, Unit 1354,The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030. Phone: 713-792-2817; Fax: 713-745- 4385; E-mail: mcristof@mdanderson.org. F 2008 American Association for Cancer Research. doi:10.1158/1078-0432.CCR-07-1479 www.aacrjournals.org Clin Cancer Res 2008;14(6) March 15, 2008 1718 Downloaded from http://aacrjournals.org/clincancerres/article-pdf/14/6/1718/1980240/1718.pdf by guest on 11 March 2024