title: Type 2 diabetes, insulin treatment and prognosis of breast cancer.
abstract: The aim of our study was to investigate whether pre-existing type 2 diabetes and insulin therapy have an impact on the prognosis of breast cancer patients.
  
  
  
  We performed a retrospective analysis of 462 type 2 diabetic breast cancer patients and 1644 non-diabetic breast cancer patients treated in our institute from January 2005 to August 2010. Patients were divided by diabetes status and insulin use. The clinicopathological characteristics and clinical outcomes of patients within 5 years following breast cancer diagnosed were analysed.
  
  
  
  Diabetic patients tended to have higher body mass index and higher histological grade tumours. Five-year disease-free survival and overall survival were reduced in diabetic patients (P < 0.001), and diabetes was an independent predictor for an increased risk of breast cancer relapse and death within 5 years (P < 0.001). Insulin treatment was associated with reduced 5-year disease-free survival and overall survival (P < 0.05); the risk of 5-year relapse and breast cancer mortality in the insulin group increased compared to that of non-insulin group after adjusting for age, tumour size, histological grade, oestrogen receptor, progesterone receptor, chemotherapy and hormone therapy (P < 0.05). After adjusting for age and other factors, the risk of breast cancer relapse was also increased in the insulin subgroup, while the risk of breast cancer mortality did not increase statistically.
  
  
  
  Type 2 diabetes and insulin treatment might be independently associated with poorer prognosis of breast cancer. However, caution is needed when interpreting our results, and further investigations are needed. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: First Department of Breast Tumor, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, Tianjin's Clinical Research Center for Cancer, Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education, Tianjin, 300060, China.
authors.forename: Lan
authors.initials: L
authors.lastname: Mu
authors.affiliation: 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital, Tianjin Medical University, Tianjin, China.
authors.forename: Nannan
authors.initials: N
authors.lastname: Zhu
authors.affiliation: First Department of Breast Tumor, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, Tianjin's Clinical Research Center for Cancer, Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education, Tianjin, 300060, China.
authors.forename: Jiao
authors.initials: J
authors.lastname: Zhang
authors.affiliation: First Department of Breast Tumor, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, Tianjin's Clinical Research Center for Cancer, Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education, Tianjin, 300060, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Xing
authors.affiliation: 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital, Tianjin Medical University, Tianjin, China.
authors.forename: Daiqing
authors.initials: D
authors.lastname: Li
authors.affiliation: First Department of Breast Tumor, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, Tianjin's Clinical Research Center for Cancer, Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education, Tianjin, 300060, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
mesh_terms: D001943:Breast Neoplasms / Q000150:complications / Q000188:drug therapy*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000627:therapeutic use*; D011379:Prognosis
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin
keywords: breast cancer; insulin; mortality; relapse; type 2 diabetes