title: Metformin Has a Positive Therapeutic Effect on Prostate Cancer in Patients With Type 2 Diabetes Mellitus.
abstract: OBJECTIVE
  Prostate cancer and type 2 diabetes mellitus (DM2) are both common diseases found in the elderly male population. The diabetic drug, metformin, has been shown to have antineoplastic properties and demonstrated better treatment outcomes when used as adjuvant therapy in patients with breast cancer. The hormonally-sensitive cancer analogous to breast cancer in men is prostate cancer. We investigated improved survival, lower risks of recurrences, and lower, more stable levels of prostate-specific antigen (PSA) in patients with DM2 along with prostate cancer on metformin.
  
  
  METHODS
  Patients with prostate cancer along with DM2 who remained on metformin were compared with controls who were not on metformin matched by age, weight, race and Gleason score cancer staging. The endpoints of our study included final PSA values, number of recurrences, metastases and number living for each group.
  
  
  RESULTS
  There were significantly fewer deaths (23% versus 10%), fewer recurrences (15% versus 8%), fewer metastases (5% versus 0%) and fewer secondary cancers (17% versus 6%) in the metformin group (P < 0.004). The final PSA value was lower in the metformin-treated group with a result approaching significance (P = 0.067). The primary treatments for prostate cancer (ie, surgery, radiation and androgen depletion) were found to be comparable in both the groups.
  
  
  CONCLUSIONS
  Our retrospective study shows that adjuvant metformin therapy leads to a better prognosis in prostate cancer. Not only are PSA levels controlled for several years but also there are significantly fewer cancer recurrences in metformin-treated patients. Overall, these results are promising and should be followed up with a prospective study to assess long-term survival.
authors.affiliation: Division of Endocrinology, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee; Department of Pharmacology, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: R William
authors.initials: RW
authors.lastname: Chong
authors.affiliation: Division of Endocrinology, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee; Department of Pharmacology, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee; Department of Medicine (Endocrinology) and Research Service, Veterans Affairs Medical Center, Memphis, Tennessee.
authors.forename: Vijaya
authors.initials: V
authors.lastname: Vasudevan
authors.affiliation: Department of Preventive Medicine, College of Medicine, Veterans Affairs Medical Center, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Zuber
authors.affiliation: Division of Endocrinology, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee; Department of Pharmacology, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee; Department of Medicine (Endocrinology) and Research Service, Veterans Affairs Medical Center, Memphis, Tennessee. Electronic address: ssolomon@uthsc.edu.
authors.forename: Solomon S
authors.initials: SS
authors.lastname: Solomon
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology*; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D008297:Male; D008687:Metformin / Q000627:therapeutic use*; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology*; D012042:Registries; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D007004:Hypoglycemic Agents; D008687:Metformin
keywords: Metformin; Prognosis; Prostate cancer; Prostate specific antigen; Type 2 diabetes mellitus