title: Metformin and cancer occurrence in insulin-treated type 2 diabetic patients.
abstract: OBJECTIVE
  Metformin is associated with reduced cancer-related morbidity and mortality. The aim of this study was to assess the effect of metformin on cancer incidence in a consecutive series of insulin-treated patients.
  
  
  METHODS
  A nested case-control study was performed in a cohort of 1,340 patients by sampling, for each case subject, age-, sex-, and BMI-matched control subjects from the same cohort.
  
  
  RESULTS
  During a median follow-up of 75.9 months, 112 case patients who developed incident cancer and were compared with 370 control subjects. A significantly lower proportion of case subjects were exposed to metformin and sulfonylureas. After adjustment for comorbidity, glargine, and total insulin doses, exposure to metformin, but not to sulfonylureas, was associated with reduced incidence of cancer (odds ratio 0.46 [95% CI 0.25-0.85], P = 0.014 and 0.75 [0.39-1.45], P = 0.40, respectively).
  
  
  CONCLUSIONS
  The reduction of cancer risk could be a further relevant reason for maintaining use of metformin in insulin-treated patients.
authors.affiliation: Section of Geriatric Cardiology and Medicine, Department of Cardiovascular Medicine, University of Florence and Careggi Teaching Hospital, Florence, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Monami
authors.forename: Claudia
authors.initials: C
authors.lastname: Colombi
authors.forename: Daniela
authors.initials: D
authors.lastname: Balzi
authors.forename: Ilaria
authors.initials: I
authors.lastname: Dicembrini
authors.forename: Stefano
authors.initials: S
authors.lastname: Giannini
authors.forename: Cecilia
authors.initials: C
authors.lastname: Melani
authors.forename: Valentina
authors.initials: V
authors.lastname: Vitale
authors.forename: Desiderio
authors.initials: D
authors.lastname: Romano
authors.forename: Alessandro
authors.initials: A
authors.lastname: Barchielli
authors.forename: Niccolò
authors.initials: N
authors.lastname: Marchionni
authors.forename: Carlo Maria
authors.initials: CM
authors.lastname: Rotella
authors.forename: Edoardo
authors.initials: E
authors.lastname: Mannucci
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000031:analogs & derivatives / Q000627:therapeutic use*; D000069036:Insulin Glargine; D049528:Insulin, Long-Acting; D008297:Male; D008687:Metformin / Q000627:therapeutic use*; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology / Q000517:prevention & control*; D013453:Sulfonylurea Compounds / Q000627:therapeutic use
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin; D049528:Insulin, Long-Acting; D013453:Sulfonylurea Compounds; D000069036:Insulin Glargine; D008687:Metformin