The effect of obesity on prognosis in operable breast cancer patients treated with adjuvant anthracyclines and taxanes according to pathologic subtypes.

Breast Cancer - Triple-Negative/Cytotoxics/Local Therapy
Session Type and Session Title: 
Poster Discussion Session, Breast Cancer - Triple-Negative/Cytotoxics/Local Therapy
Abstract Number: 
J Clin Oncol 31, 2013 (suppl; abstr 1031)
Marina Pollán, Bella Pajares, Miguel Martin, John Robert Mackey, Ana Lluch, Joaquin Gavila, Charles L. Vogel, Manuel Ruiz Borrego, Lourdes Calvo, Tadeusz Pienkowski, Alvaro Rodriguez-Lescure, Miquel Angel Seguí, Olivier Tredan, Antonio Anton, Manuel Ramos Vazquez, M Carmen Camara, Cesar Rodriguez-Martin, Eva Maria Carrasco, Emilio Alba, Spanish Breast Cancer Research Group (GEICAM); National Center of Epidemiology, Instituto Salud Carlos III, Madrid, Spain; Hospital Universitario Virgen de la Victoria, Malaga, Spain; Medical Oncology, Instituto de Investigación Sanitaria Gregorio Marañon, Universidad Complutense, Madrid, Spain; Department of Oncology, Cross Cancer Institute, Edmonton, AB, Canada; Hospital Clínico de Valencia - INCLIVA Health Research Institute, University of Valencia., Valencia, Spain; Instituto Valenciano de Oncologia, Valencia, Spain; University of Miami School of Medicine, Comprehensive Cancer Research Group, Inc., Miami, FL; Hospital Universitario Virgen del Rocio, Seville, Spain; Complexo Hospitalario Universitario de A Coruña, A Coruna, Spain; Department of Oncology, Postgraduate Medical Center, Warsaw, Poland; Hospital General de Elche, Alicante, Spain; Hospital de Sabadell, Corporació Sanitària Parc Taulí, Institut Oncològic del Vallès, Sabadell, Spain; Centre Léon Bérard, Lyon, France; Hospital Universitario Miguel Servet, Zaragoza, Spain; Centro Oncológico de Galicia, A Coruña, Spain; GEICAM, Madrid, Spain; GEICAM, SS de los Reyes, Spain; Hospital Clínico Universitario Virgen de la Victoria, Malaga, Spain

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Abstract Disclosures


Background: According to observational studies, obesity is an unfavourable prognostic factor in breast cancer (BC), regardless of menopausal status and treatment received. Information collected in clinical trials should confirm this effect and serves to test its homogeneity by pathologic subtype. Methods: We retrospectively analysed 5,683 operable BC patients enrolled in four randomized clinical trials (GEICAM/9906, 9805, 2003–02, and BCIRG 001) evaluating adjuvant anthracyclines and taxanes. Our primary aim was to assess the prognostic effect of body mass index (BMI) on disease recurrence, breast cancer mortality (BCM), and overall mortality (OM). A secondary aim was to detect differences by BC subtypes (ER/PR-positive/HER2-negative, HER2-positive, triple-negative). Cox models were fitted for each end-point, adjusted by potential confounders. Results: Analyses adjusting for age, tumor size, nodal status, menopausal status, surgery, grade, hormone receptor and HER2 status, chemotherapy regimen, and undertreatment showed that obese patients (BMI 30.0–34.9) had similar prognoses to that of patients with a BMI<25 (reference group) in terms of recurrence (HR 1.08 [95% CI 0.9–1.3]; p=0.41), BCM (HR 1.02 [0.81–1.29]; p=0.85), and OM (HR 0.97 [0.78–1.19]; p=0.747). Patients with severe obesity (BMI≥35) had a significantly increased risk of recurrence (HR 1.26 [1.00–1.59]; p=0.05), BCM (HR 1.32 [1.00–1.74]; p=0.05), and OM (HR 1.35 [1.06–1.71]; p=0.02) compared to our reference group (Table). The prognostic effect of severe obesity did not vary by subtype. Conclusions: Severely obese patients treated with anthracyclines and taxanes present a worse prognosis regarding recurrence, BCM, and OM than patients with a BMI<25. The magnitude of the harmful effect of BMI was similar across subtypes.

Overall mortality
Breast cancer mortality
HR 95% CI p HR 95% CI p HR 95% CI p
<25 1.00 1.00 1.00
25-29.9 0.95 0.80-1.12 0.53 1.01 0.84-1.22 0.89 1.03 0.89-1.20 0.65
30-34.9 0.97 0.78-1.19 0.75 1.02 0.81-1.29 0.85 1.08 0.90-1.30 0.41
>=35 1.35 1.06-1.71 0.02 1.32 1.00-1.74 0.05 1.26 1.00-1.59 0.05