17862
RESULTS : Analysis of 24 metformin studies in subjects with T2DM showed that metformin use is associated with reduced risk for the development of cancer , in both cohort ( RR = 0 . 70 [ 95 % CI = 0 . 67 - 0 . 73 ] ) and case - control studies ( OR = 0 . 90 [ 95 % CI = 0 . 84 - 0 . 98 ] ) , but this finding was not supported by RCTs ( RR = 1 . 01 [ 95 % CI = 0 . 81 - 1 . 26 ] ) .
 Chemical: metformin; Chemical: metformin
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: metformin, metformin 
Answer:
 Chemical: metformin; Chemical: metformin