BACKGROUND AND PURPOSE:

• There are previous reports of reduced risk of cancers, including ovarian cancer in individuals with type 2 diabetes (T2D) being managed with metformin
• Statin use has also been associated with reduced risk of cancer in some papers while there are other reports of women with T2D having an increased incidence of various cancers, including ovarian cancer especially in those treated with insulin
• Many of these studies had methodological flaws, including smaller sample sizes
• Urpilainen et al. (BJOG, 2018) assessed the impact of metformin and statin use on rates of ovarian cancer in women with type 2 diabetes (T2D)

METHODS:

The authors used 2 different study designs

Cohort Study

• Data was obtained from the diabetes database (FinDM) combining information from several Finnish nationwide registers
• Women were over 40 years old and diagnosed with T2D
• Hazard ratio (HR) was used to determine the relationship between ovarian cancer and ever use of
  • Metformin
  • Insulin
  • Other anti-diabetic medication
  • Statins

Case Control Study

• 20 controls were matched to each case of ovarian cancer
• Conditional logistic regression was used to estimate HRs in relation to medication use and cumulative use of different medications

RESULTS:

• Data was collected from 137,643 women (mean follow up 5.4 years)
  • 303 women were diagnosed with ovarian cancer
  • Incidence of ovarian cancer was highest in women age 60-69 years
• For the case control study, 6060 controls were matched to the 303 cases of ovarian cancer based on age and T2D duration
• Compared with other forms of oral anti-diabetic medication, metformin was not found to be associated with the incidence of ovarian cancer
  • HR 1.02; 95% CI, 0.72-1.45
• There was also no evidence that statins affect the incidence of ovarian cancer
  • HR 0.99, 95% CI: 0.78-1.25
• In the nested case-control analysis, the results were similar and no associations were found between metformin or statins and ovarian cancer
• There was no increased risk of ovarian cancer in women with T2D treated with insulin

CONCLUSION:

• There was no measured association between the use of metformin or statins and risk for ovarian cancer in women with T2D

Learn More – Primary Sources:

The role of metformin and statins in the incidence of epithelial ovarian cancer in type 2 diabetes: a cohort and nested case-control study.

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