title: Relationship between body mass index and the expression of hormone receptors or human epidermal growth factor receptor 2 with respect to breast cancer survival.
abstract: BACKGROUND
  The association between body mass index (BMI) at the time of breast cancer diagnosis and the prognosis of breast cancer patients remains controversial. Furthermore, the association between BMI and prognosis with respect to different breast cancer subtypes is not clearly defined.
  
  
  METHODS
  We analyzed data from 41,021 invasive breast cancer patients between January 1988 and February 2008 from the Korean Breast Cancer Registry (KBCR) database. Overall survival (OS) and breast cancer-specific survival (BCSS) were analyzed using the Kaplan-Meier method and Cox's proportional hazard regression model among all patients and specific breast cancer subtypes with respect to BMI categories.
  
  
  RESULTS
  A U-shaped association between BMI and mortality was observed in the total cohort. Underweight and obese individuals exhibited worse OS (hazard ratio, 1.23 [95 % confidence interval {CI}, 1.05 to 1.44] and 1.29 [1.13 to 1.48], respectively) and BCSS (1.26 [1.03 to 1.54] and 1.21 [1.02 to 1.43], respectively) than normal-weight individuals. In the estrogen receptor (ER) and/or progesterone receptor (PR)+/human epidermal growth factor receptor 2 (HER2) - subgroup, obese individuals exhibited worse OS (1.48 [1.18 to 1.85]) and BCSS (1.31 [1.13 to 1.52]) than normal-weight individuals. Conversely, in the ER and PR-/HER2+ subgroup, underweight individuals exhibited worse OS (1.68 [1.12 to 2.47]) and BCSS (1.79 [1.11 to 2.90]) than normal-weight individuals.
  
  
  CONCLUSIONS
  We observed a U-shaped relationship between BMI at diagnosis and poor OS and BCSS among all breast cancer patients. However, obesity in the ER and/or PR+/HER2- subgroup and underweight in the ER and PR-/HER2+ subgroup were poor prognostic factors. Therefore, BMI at diagnosis and breast cancer subtype should be considered simultaneously in various treatment decision processes and surveillance schedules.
authors.affiliation: Department of Surgery, St. Vincent's Hospital, College of Medicine, The Catholic University, 93 Joongboo-Daero Paldal-gu, Suwon, 442-723, Kyunggi-do, Republic of Korea. yeswon80@catholic.ac.kr.
authors.forename: Ye Won
authors.initials: YW
authors.lastname: Jeon
authors.affiliation: Department of Surgery, Yeungnam University College of Medicine, 170 Hyunchung-ro, Nam-gu, Deagu, 705-703, Republic of Korea. kangsuhwan@yu.ac.kr.
authors.forename: Su Hwan
authors.initials: SH
authors.lastname: Kang
authors.affiliation: Department of Surgery, Chonnam National University Medical School, 160 Baekseo-ro, Dong-gu, Gwangju, 501-746, Republic of Korea. thokthok@hanmail.net.
authors.forename: Min Ho
authors.initials: MH
authors.lastname: Park
authors.affiliation: Department of Surgery, Ewha Womans University, Mokdong hospital, 1071, Anyangcheon-ro, Yangcheon-gu, Seoul, 158-710, Republic of Korea. limw@ewha.ac.kr.
authors.forename: Woosung
authors.initials: W
authors.lastname: Lim
authors.affiliation: Department of Surgery, Dong-A University College of Medicine, 26, Daesingongwon-ro, Seo-gu, Busan, 602-715, Republic of Korea. shcho1@dau.ac.kr.
authors.forename: Se Heun
authors.initials: SH
authors.lastname: Cho
authors.affiliation: Department of Surgery, St. Vincent's Hospital, College of Medicine, The Catholic University, 93 Joongboo-Daero Paldal-gu, Suwon, 442-723, Kyunggi-do, Republic of Korea. yjsuh@catholic.ac.kr.
authors.forename: Young Jin
authors.initials: YJ
authors.lastname: Suh
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics / Q000378:metabolism* / Q000401:mortality* / Q000628:therapy; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008875:Middle Aged; D060787:Neoplasm Grading; D011379:Prognosis; D016016:Proportional Hazards Models; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000235:genetics / Q000378:metabolism*; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone