Use of metformin and survival of diabetic women with breast cancer

TY - JOUR

T1 - Use of metformin and survival of diabetic women with breast cancer

AU - Peeters, Paul J H L

AU - Bazelier, Marloes T

AU - Vestergaard, Peter

AU - Leufkens, Hubert G M

AU - Schmidt, Marjanka K

AU - de Vries, Frank

AU - De Bruin, Marie L

PY - 2013/12

Y1 - 2013/12

N2 - OBJECTIVE: This study was set out to determine whether metformin use influences survival in breast cancer patients treated with antidiabetic drugs as compared to non-users.RESEARCH DESIGN AND METHODS: We used data from the Danish national registries (1996-2008) to identify adult female patients diagnosed with breast cancer who were prescribed antidiabetic medication. We performed multivariate Coxproportional hazard regression to assess all-cause and breast cancer-specific mortality risks associated with metformin exposure. In a secondary analysis, we stratified use of metformin according to the cumulative number of prescriptions.RESULTS: Of the 1058 breast cancer patients 349 died during follow-up, with breast cancer listed as the primary cause of death for 152 cases. Compared to non-use, current metformin treatment was associated with a significant reduction in overall mortality (adjusted HR 0.74, 95% CI, 0.58-0.96). For breast cancer-specific mortality, a non-significant risk reduction (adjusted HR 0.88, 95% CI, 0.59-1.29) was observed, which became significant after stratification according to cumulative number of prescriptions. An increased risk of both overall and breast cancer-specific mortality was observed in the first 12 months after discontinuation of metformin.CONCLUSIONS: We observed a nonsignificant reduction in breast cancer-specific mortality associated with metformin exposure among breast cancer patients treated with antidiabetic drugs. However, our findings suggest that long-term metformin use may have a beneficial effect on survival in patients with breast cancer. Further confirmation of these findings is needed.

AB - OBJECTIVE: This study was set out to determine whether metformin use influences survival in breast cancer patients treated with antidiabetic drugs as compared to non-users.RESEARCH DESIGN AND METHODS: We used data from the Danish national registries (1996-2008) to identify adult female patients diagnosed with breast cancer who were prescribed antidiabetic medication. We performed multivariate Coxproportional hazard regression to assess all-cause and breast cancer-specific mortality risks associated with metformin exposure. In a secondary analysis, we stratified use of metformin according to the cumulative number of prescriptions.RESULTS: Of the 1058 breast cancer patients 349 died during follow-up, with breast cancer listed as the primary cause of death for 152 cases. Compared to non-use, current metformin treatment was associated with a significant reduction in overall mortality (adjusted HR 0.74, 95% CI, 0.58-0.96). For breast cancer-specific mortality, a non-significant risk reduction (adjusted HR 0.88, 95% CI, 0.59-1.29) was observed, which became significant after stratification according to cumulative number of prescriptions. An increased risk of both overall and breast cancer-specific mortality was observed in the first 12 months after discontinuation of metformin.CONCLUSIONS: We observed a nonsignificant reduction in breast cancer-specific mortality associated with metformin exposure among breast cancer patients treated with antidiabetic drugs. However, our findings suggest that long-term metformin use may have a beneficial effect on survival in patients with breast cancer. Further confirmation of these findings is needed.

KW - Adolescent

KW - Adult

KW - Aged

KW - Aged, 80 and over

KW - Breast Neoplasms

KW - Cohort Studies

KW - Comorbidity

KW - Denmark

KW - Diabetes Mellitus

KW - Female

KW - Follow-Up Studies

KW - Humans

KW - Hypoglycemic Agents

KW - Metformin

KW - Middle Aged

KW - Registries

KW - Risk Factors

KW - Survival

KW - Treatment Outcome

KW - Young Adult

KW - Journal Article

M3 - Journal article

C2 - 24215316

SN - 1574-8863

VL - 8

SP - 357

EP - 363

JO - Current Drug Safety

JF - Current Drug Safety

IS - 5

ER -