Safety and cost-effectiveness of immediate right hemicolectomy versus active surveillance for well-differentiated appendiceal neuroendocrine tumors 1-2 cm in size: a Markov decision analysis

PurposeTherapeutic management of appendiceal neuroendocrine neoplasms (a-NENs) 10-20 mm in size represents a challenge for both surgeons and oncologists. We compared active surveillance after appendectomy versus immediate right hemicolectomy (RHC).MethodsA Markov decision model was developed based on literature parameters. The endpoints were the life expectancy, the quality-adjusted life expectancy (QALY), and the cost-effective ratio expressed by the incremental cost-effective ratio (ICER). A deterministic sample analysis (DSA) with one-way sensitivity analysis was performed for the base case scenario. A probabilistic sensitivity analysis (PSA) was performed to solve the uncertainty of the model. Montecarlo simulation with 100,000 replications for each arm was used. Data are reported in US$. The acceptability of the strategy was set 3 times ($130,049) the Euro area's gross domestic product per capita ($43,394).ResultsThe 10-year survival rates for active surveillance and immediate RHC were 98.2 and 98.9%, respectively. The DSA showed the superiority of active surveillance versus immediate RHC (10 versus 9.0 QALY). Active surveillance costs more than immediate RHC ($35,761 vs. $39,486). The resulting ICER was $4302 per QALY. The model was more sensitive to the length of follow-up (99.9% variability): the longer the surveillance, the higher the ICER (spread $302,703). PSA analysis confirmed active surveillance as the most cost-effective choice, costing an ICER + $4059 per QALY.ConclusionActive surveillance is safe and cost-effective in patients with appendiceal NENs of 10-20 mm in size, both clinically and economically.