Table 2.
Studies on the effects of metformin use on cancer-specific mortality and overall mortality of prostate cancer.
| Author (Country) | Population | Period | No. Cases/Controls | Risk Estimates (95% CI) | Adjusted Variables |
|---|---|---|---|---|---|
| Mayer (Canada) [73] | Patients receiving docetaxel chemotherapy | 2005–2012 | 359/2473 | CSM HR: 0.96, 95% CI: 0.79–1.16 OM HR: 0.94, 95% CI: 0.82–1.08 |
Age, use of statins and COX-2i, socio-economic status, urban/rural designation |
| Zaorsky (US) [72] | Patients receiving radiation therapy | 1998–2013 | 251/2352 | CSM sub-HR: 2.13 (0.90–5.08) OM sub-HR: 0.99 (0.65–1.52) |
Age, comorbidities, PSA (log-transformed), Gleason score, T stage, ADT |
| Joentausta (Finland) [74] | Patients receiving radical prostatectomy | 1995–2009 | 28/136 | OM age-adjusted HR: 1.98 (0.86–4.53) multivariate-adjusted HR: 1.53 (0.57–4.08) |
Age, use of 5αRI, preoperative PSA |
| Xu (US) [77] | Patients diagnosed with PCa, mixed therapy | 1995–2010 | 3029/5910 | OM (adjusted HR) Vanderbilt group: 1.04 (0.66–1.67) Mayo group: 0.69 (0.52–0.93) |
Age, sex, race, BMI, tobacco use, insulin, cancer type, CCI |
| Randazzo (Switzerland) [69] | PSA-screened cohort, mixed therapy | 1998–2003 | 150/4164 | CSM OR: 27.94 (1.73–448.8) OM HR: 2.14 (1.19–3.87) |
Age, PSA, family history, IPSS |
| Bensimon (UK) [71] | Patients newly diagnosed with non-metastatic PCa, mixed therapy | 1998–2009 | 78/194 | CSM overall RR: 1.09 (0.51–2.33) cumulative duration >938 days RR: 3.20 (1.00–10.24) OM post-diagnostic use of metformin RR: 0.79 (0.50–1.23) |
Age, BMI, CCI, smoking, PSA, Gleason score, HbA1c excessive alcohol use, use of anti-diabetic agents (metformin, sulfonylureas, thiazolidinediones, insulins) |
| Spratt (Canada) [70] | Patients receiving radiation therapy | 1992–2008 | 157/162 | CSM (adjusted HR) non-diabetic group: 2.68 (0.85–8.44) * diabetic non-metformin group: 5.15 (1.53–17.35) * OS Non-diabetic group: 1.38 (0.90–2.11) * diabetic non-metformin group: 2.25 (1.38–3.66) * |
Age, risk group, T stage, Gleason score, PSA, neoadjuvant ADT, BMI |
| Taira (US) [75] | Patients receiving interstitial brachytherapy | 1995–2010 | 126/2172 | OM HR: NA (p = 0.873) |
Age, %positive biopsy, T stage, Gleason score, PSA, ADT duration, BMI, comorbidities |
| Margel (US) [78] | Patients newly diagnosed with PCa, mixed therapy | 1997–2008 | 1251/2586 | CSM HR: 0.76 (0.64–0.89) |
Age, Johns Hopkins ACG Case-Mix System weighted sum of adjusted diagnostic groups, year of cohort entry, socioeconomic status, COX-2i, statins |
ACG: adjusted clinical group; ADT: androgen-deprivation therapy; BMI: body mass index; CCI: Charlson Comorbidity Index; CI: confidence interval; COX-2i: cyclooxygenase-2 inhibitor; CRPC: castration-resistant prostate cancer; CSM: cancer-specific mortality; 5αRI: 5alpha reductase inhibitor; HbA1c: hemoglobin A1c; HR: hazard ratio; OM: overall mortality; OR: odds ratio; OS: overall survival; PCa: prostate cancer; PSA: prostate-specific antigen. * metformin group as reference.