OBJECTIVES: CUA of cryosurgery, topical treatments (diclofenac 3% 12 weeks, imiquimod 3.75% 6 weeks or 5% 4/8 weeks, ingenol mebutate gel (IMG) 0.015%/head 3 days or 0.05%/body 2 days), and methyl aminolevulinate + photodynamic therapy (MAL+PDT) in the treatment of 25cm AK-plague affecting any body part. METHODS: A sequential probabilistic decision-tree with 2-year time-horizon was used to assess the cost-utility (incremental cost-effectiveness ratio, ICER) of AK-treatments, and to determine the cost-effectiveness acceptability frontier (CEAF) and expected value of perfect information per patient (EVPI) from health care payer perspective. In the model, the first-line AK-treatment resulted in complete clearance (CC) with or without adverse events (AE), non-CC or AK-recurrence. Non-CC AK was retreated with PDT and AK-recurrence was retreated with the previous treatment. Incident AK-patients (year 2009, n=3409, organ transplant patients excluded) were identified from the Finnish hospital discharge register to assess AK-related 2-year secondary health care costs for patients initiating different treatment regimens. Other costs included general practitioner, AE-management, and outpatient drugs (5/2014 without VAT; other costs in 2013 value). Quality-adjusted life-years (QALY) were based on EQ-5D. Results were discounted with 3% annually. RESULTS: The mean per patient 2-year QALYs (costs) were 1.519 (€727) for IMG 0.015%, 1.518 (€887) for MAL+PDT, 1.516 (€802) for IMG 0.05%, 1.514 (€995) for diclofenac, 1.512 (€815) for imiquimod 3.75%, 1.511 (€707) for imiquimod 5%, and 1.507 (€1010) for cryosurgery. IMG 0.015% had €2806/QALY gained ICER against imiquimod 5%, and dominated other AK-treatments. IMG 0.05% dominated diclofenac, imiquimod 3.75% and cryosurgery, and had €21,550/QALY gained ICER against imiquimod 5%. MAL+PDT had €32,848/QALY gained ICER against IMG 0.05%. Based on the CEAF, IMG 0.015% was the optimal treatment when willingness-to-pay/QALY gained exceeded €2806. The EVPI was €25/€81/€211 with the willingness-to-pay of €0/€15,000/€30,000 per QALY gained. CONCLUSIONS: IMG 0.015% was the most cost-effective first-line AK-treatment.