Ko and colleagues have recently reported that metformin may improve survival in women with endometrial cancer . They retrospectively studied 1495 women who were diagnosed between 2005 and 2010 at two tertiary US academic institutions. Median follow-up was 33 months. Demographic, pathological, clinical and follow-up data were obtained from medical records. Body mass index (BMI) and data on use of metformin, insulin, sulfonamide and thiazolidinedione at the time of cancer diagnosis were obtained. Information on recurrence and death were recorded from clinical and/or electronic data and/or from the Social Security Death Index. Causes of death were not available for all patients. A total of 363 women (24%) had diabetes mellitus, of whom 55% used metformin ([i]n[/i] = 200). Some metformin-treated women were also using other treatments, including 34% on sulfonylureas, 18% on thiazolidinediones, 15% on insulin, and 7% on other anti-diabetics. Metformin users were younger (median 62.2 vs. 64.8 years) and heavier (median (interquartiles] BMI = 38 [33–34] vs. 36 [31–42] kg/m[+]2[/+]; [i]p[/i] = 0.004) than non-metformin-users. Pathologic findings were similar by stage and grade in both groups, although histology was significantly different between groups (despite this, 75% in both groups were endometrioid endometrial carcinomas).
Recurrence-free survival (RFS; %) was decreased more while overall survival was increased more in metformin users than in non-metformin users: non-metformin users had a 1.7% worse RFS (adjusted value 1.8%) and were 2.0 (adjusted value 2.3) times more likely to die as compared with metformin users. Time to recurrence was not significantly different between the groups.
Faustino R. PÃ©rez-LÃ³pez
Professor of Obstetrics and Gynecology, University of Zaragoza Faculty of Medicine & Lozano Blesa University, Hospital, Zaragoza, Spain