Therapeutic Use of Metformin in Diabetes and Survival Outcomes in Endometrial Cancer Patients with Diabetes

Document Type: Research Articles

Authors

1 Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Rajavithi Hospital, Bangkok, Thailand.

2 College of Medicine, Rangsit University, Bangkok, Thailand.

Abstract

Objectives: To compare survival outcomes between endometrial cancer (EC) patients with diabetes who used
metformin to those who did not use metformin. Materials and Methods: A retrospective cohort study was conducted
of EC patients who were diabetes at the time of their cancer diagnosis and had been scheduled for elective surgery
at Rajavithi Hospital between 1 January 2003 and 31 December 2013. The patients were excluded if they had type
I diabetes mellitus and a history of other cancers. Results: Of 1,262 EC patients in the study period, there was 212
(16.8%) patients who met the inclusion criteria. Among them, 90 (42.5%) were non-metformin users and 122 (57.5%)
were metformin users. With a median follow-up of 47 months, the 5-year overall survivals (76.4% vs 77.9%, p=0.959)
and the 5-year progression-free survivals (92.6% vs 84.7%, p=0.091) did not significantly differ between the both
groups. On Cox proportional-hazards regression analysis, independent prognostic factors for overall survival (OS)
were FIGO stage, depth of myometrial invasion, and cervical involvement. Patients with non-endometrioid histology
and advanced stage were found to have a significant effect on progression-free survival (PFS). However, metformin
used did not predict either OS (HR, 0.99; 95%CI, 0.56-1.73; p=0.959) or PFS (HR, 2.19; 95%CI, 0.86-5.55; p=0.099).
Conclusion: Overall, a significant effect of metformin on survival outcomes in EC patients with diabetes was not found
in the current study. Larger studies with a prospective randomized control design are needed to clarify the benefit of
metformin as a strategy for endometrial cancer prevention and treatment.

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