Patients receiving both metformin and insulin (n = 30) had a higher proportion of histological grade II tumors (96.7% vs. 67.1%; p = 0.001), a lower frequency of pTNM stage I disease (6.7% vs. 29.3%; p = 0.010), and a significantly higher rate of DCIS (23.3% vs. 0%; p < 0.001) compared to those receiving neither drug (Table 3). Here, INS is linked to ductal breast carcinoma in situ.