108P - Metformin effect on a cohort of non-diabetic patients with early breast cancer in a window of opportunity study

Date 20 December 2015
Event ESMO Asia 2015 Congress
Session Poster presentation 2
Topics Breast Cancer
Presenter Maasumeh Saberian
Citation Annals of Oncology (2015) 26 (suppl_9): 16-33. 10.1093/annonc/mdv519
Authors S. Sadighi, M. Najafi, M.S. Saberian, I. Jahanzad, R. Omranipoor
  • Medical Oncology, Cancer Institute, 1419733141 - Tehran/IR



We design a prospective controlled study about metformin efficacy in the window time between biopsy and definite surgery with changes of Ki67 as the primary endpoint.


Non-diabetic patients with invasive breast cancer accrued in Medical Oncology Department of Iran Cancer Institute from Feb to Nov 2014. They followed between biopsy and definitive surgery, taking tests on pathology specimens for ER, PgR, HER2 and KI67. We checked fasting blood insulin and sugar level as well as quality of life and adverse effects in both times. Metformin (1500 mg/day) was prescribed to intervention group from pathology report to the night before surgery. Control group were patients with the same inclusion criteria who did not receive any drug between biopsy and surgery.


From 50 patients enrolled 5 excluded. Four without using any pills and one at the first day of taking metformin; 25 had been received metformin for median time of 2.8 weeks. Controlled group included 20 patients. There were no statistically significant differences between two groups regarding baseline clinical and tumor characteristics such as age, stage, grade, Er, Pgr, HER2 status, time and type of surgery. However, immunohistochemistry study showed decrease of median KI67 from 35.14 to 29.6 in the intervention group and increase in the control group. The diference was statistically significant. Patients tolerated metformin very well. There was a correlation between metabolic factor of HOMA score (fasting insulin level*fasting blood sugar/405) and changes in KI67.


Metformin prescription between Biopsy and definite surgery had shown inhibition of breast cancer proliferation index. We found relationship this effect and glucose and insulin metabolism.

Clinical trial identification

Cancer Research Center on Iran Cancer Institute under observation of Research Deputy of Tehran U Medical Sciences approved proposal at Dec



study funded by Research Deputy of Tehran U Medical School.