[Effect of previous diabetes therapy on tumor receptor phenotype in breast cancer: comparison of metformin and sulphonylurea derivatives].

According to some existing data, unlike sulphonylurea (SU) and insulin derivatives, treatment with biguanide metformin, for reasons still unknown, may diminish breast cancer (BC) morbidity in diabetic females. For its part, diabetes is known to worsen survival of BC patients although there is no evidence of a pathway by which antidiabetic therapy might influence the key prognostic feature of BC tissue--the tumor receptor phenotype. Combination of BC and diabetes (n=90) was studied. SU drugs were received for at least 12 months by 22 patients, biguanide metformin alone or in conjunction with SU by 15, insulin by 5, and dietary treatment alone--by 48 pts. Percentage of estrogen receptor-positive tumors did not vary significantly from group to group. However, progesterone receptor-positive (PR+) tumors in metformin-treated patients were revealed more often than in those receiving SU alone (p = 0.43) or with insulin (p = 0.041), respectively. Hence, previous treatment with metformin is expected lead to higher incidence of PR+ tumors which in turn may stimulate efficiency of hormonal therapy only in relevant group of diabetic BC patients.