The association of diabetes and anti-diabetic medications with clinical outcomes in multiple myeloma

Background:

Insulin/insulin-like growth factor-1 signalling may underlie the promoting effect of type 2 diabetes on cancer. This study examined the association of diabetes, including steroid-induced diabetes (SID), and the impact of anti-diabetic medication on clinical outcomes of multiple myeloma (MM).

Methods:

A retrospective review was conducted of 1240 MM patients. Overall survival (OS) and MM disease status prior to death were analysed.

Results:

Diabetic patients had a significantly shorter OS than non-diabetic patients (median: 65.4 vs 98.7 months). In multivariate analysis, SID was a significant predictor of decreased OS, along with age, comorbidity, MM stage, and cytogenetic abnormalities. Analyzing only the diabetic MM patients, Cox regression showed that metformin predicted an increased OS, whereas use of insulin/analogues predicted a decreased OS. Competing risk analysis showed that DM was associated with increased cumulative incidence of death with progressive MM. Among the diabetics, multivariate regression showed that insulin/analogues were associated with increased, but metformin with decreased death with progressive MM. Potential immortal time bias was evaluated by landmark analyses.

Conclusions:

DM, SID in particular, is associated with poor clinical outcomes in MM. Insulin/analogues are associated with poor outcomes, whereas metformin is associated with improved outcomes. No conclusion about causal relationships can be made at this time. Managing hyperglycaemia with non-insulin regimens should be investigated in randomised trials.

Metformin and thiazolidinediones are associated with improved breast cancer-specific survival of diabetic women with HER2+ breast cancer

BACKGROUND

Insulin/insulin-like growth factor-I (IGF-I) signaling is a mechanism mediating the promoting effect of type 2 diabetes (DM2) on cancer. Human epidermal growth factor receptor (HER2), insulin receptor and IGF-I receptor involve the same PI3K/AKT/mTOR signaling, and different antidiabetic pharmacotherapy may differentially affect this pathway, leading to different prognoses of HER2+ breast cancer.

METHODS

We reviewed 1983 consecutive patients with HER2+ breast cancer treated between 1 January 1998 and 30 September 2010. The overall survival, breast cancer-specific death rate, age, race, nuclear grade, stage, menopausal status, estrogen and progesterone receptor status, body mass index and classes of antidiabetic pharmacotherapy were analyzed.

RESULTS

A Cox regression analysis showed that DM2 [P=0.026, hazard ratio (HR)=1.42, 95 % confidence interval (95 % CI) 1.04-1.94] predicted poor survival of stage≥2 HER2+ breast cancer. In Kaplan-Meier analysis, metformin predicted lengthened survival and so did thiazolidinediones. Analyzing only the diabetics, Cox regression showed that metformin (P=0.041, HR=0.52, 95 % CI 0.28-0.97) and thiazolidinediones (P=0.036; HR=0.41, 95% CI 0.18-0.93) predicted lengthened survival, and competing risk analysis showed that metformin and thiazolidinediones were associated with decreased breast cancer-specific mortality (P=0.023, HR=0.47, 95% CI 0.24-0.90 and P=0.044, HR=0.42, 95 % CI 0.18-0.98, respectively).

CONCLUSIONS

Thiazolidinediones and metformin users are associated with better clinical outcomes than nonusers in diabetics with stage≥2 HER2+ breast cancer. The choice of antidiabetic pharmacotherapy may influence prognosis of this group.

Thiazolidinediones and metformin associated with improved survival of diabetic prostate cancer patients

BACKGROUND

The association between antidiabetic medications and the prognosis of human prostate cancer has not been explored. This study examined the impact of these drugs on the outcomes of diabetic patients with prostate cancer to provide a basis for diabetes management strategy in these patients.

PATIENTS AND METHODS

Records of consecutive prostate cancer patients with coexisting diabetes mellitus type 2 who were treated at the study institution between 15 July 1999 and 31 December 2008 were reviewed. The survival, cancer pathological grade, stage at the time of diagnosis, and antidiabetic pharmacotherapy of the patients were analyzed.

RESULTS

A total of 233 consecutive cases were analyzed. In Kaplan-Meier analysis, thiazolidinedione (log-rank, P = 0.005) and metformin (log-rank, P = 0.035) usage were significant predictors of improved overall survival, while insulin and insulin secretagogue usage were not significant predictors. Multivariate Cox regression analysis showed that thiazolidinedione {hazard ratio [HR] = 0.454 [95% confidence interval (CI) 0.213-0.965], P = 0.040} and metformin [HR = 0.550 (95% CI 0.315-0.960), P = 0.035] usage remained as significant predictors of favorable survival after controlling for variables including age, race, Gleason grade, and stage.

CONCLUSIONS

Thiazolidinediones and metformin appear to be associated with improved overall survival of diabetic prostate cancer patients. The choice of antidiabetic pharmacotherapy may influence overall survival of these patients.