The invention relates to a stable water-in-oil emulsion composition containing: 20% to 40% (v/v) aqueous phase in the form of droplets and containing an anti-cancer agent； and 60% to 80% (v/v) lipid phase containing an iodized oil and at least one surfactant, having Formula (I) as follows, in a proportion, of surfactant mass relative to the total volume of the composition, of 0.3% to 5%:wherein s is 0 or 1, m is a whole number from 2 to 30, R1 has Formula (II) as follows, and R2 and R3 are independently H or R1:wherein n is a whole number from 4 to 10, o is a whole number from 1 to 4, p is a whole number from 3 to 7, q is a whole number from 2 to 10, and r has a value of 0 or 1.
