Cost-effectiveness Analysis for Cervical Cancer Screening and Vaccination with Markov Decision Model

Autor: Hui-Shan Liu, 劉惠珊
Rok vydání: 2012
Druh dokumentu: 學位論文 ; thesis
Popis: 100
Background Population-based screening for cervical cancer with Pap smear has been widely used worldwide since 1960s and demonstrated to lead to a remarkable reduction of mortality. However, as the reduction of mortality after Pap smear screening has shown a plateau, we still need a breakthrough for cervical cancer prevention. Therefore, screening policy with HPV DNA testing and HPV vaccination are considered as alternative preventive strategies. The additional effectiveness on the basis of economic evaluation from these two related preventive strategies combined with different scheduled Pap smear screening programs has been rarely addressed. Compared with triennial screening program, studies on cost-effectiveness analysis on various combinations of preventive strategies are also limited. Purpose We aimed to elucidate the efficacy and cost-effectiveness of different preventive strategies for cervical cancer screening. Methods The probabilistic cost-effectiveness analysis of various preventive strategies in reduction of cervical cancer mortality and life cost was elucidated by using a population-based study targeted to 150,000 women in Taiwan. A Markov cycle process was defined as a series of multi-state outcome including healthy, HPV infection, CIN1, CIN2+, carcinoma in situ, invasive cancer, and death. Total of 16 preventive strategies considering screening intervals (annually, triennially, 3 yearly for age under 50 and 5 yearly for age over 50, and 5 yearly), screening modalities (HPV DNA testing, Pap smear), and HPV vaccination are further developed to compare with triennial Pap smear screening strategy used in current clinical practice. The parameters for analysis were derived from literatures. By assigning the specific statistical distribution to each parameter, Monte Carlo simulation with 5000 microsimulation trials was therefore applied to capture the parameter uncertainty. We then present the outcome in terms of incremental cost-effectiveness ratios (ICERs) per life-year gained and incremental net benefit (INB) under varying prevention strategies compared with triennial Pap smear screening program. Result In terms of elucidating the effectiveness of different strategies in our study, we have the following main finding, 1. Compared with triennial Pap smear, annual Pap smear reduced the 11% of pre-cancer lesions, 43% of invasive cervical cancer, and 45% of cervical cancer death. 2. Compared with triennial Pap smear, annual HPV DNA testing and Pap smear reduced the 17% of pre-cancer lesions, 54% of invasive cervical cancer, and 55% of cervical cancer death. 3. Compared with triennial Pap smear, vaccination and annual Pap smear reduced the 29% of pre-cancer lesions, 56% of invasive cervical cancer, and 56% of cervical cancer death. 4. Compared with triennial Pap smear, vaccination together with annual HPV DNA testing and Pap smear reduced the 33% of pre-cancer lesions, 59% of invasive cervical cancer, and 60% of cervical cancer death. The marginal effect of vaccination therefore might be reckoned around 5-24% under different prevention strategies. The incremental cost-effectiveness ratios for annual Pap smear against the triennial Pap smear were calculated as $41,991 and $23,093 for per cervical cancer prevented and per life-year gained, respectively. The corresponding figures for vaccination program with annual HPV DNA testing followed by Pap smear against the triennial Pap smear were calculated as $59,375 and $34,306 for per cervical cancer prevented women and per life-year gained, respectively given the threshold of $50,000 of willingness to pay. Compared with triennial Pap smear, the probability of being cost-effective by the acceptability curve were 99.5% for annual Pap smear and 95.5% for vaccination program with annual HPV DNA testing followed by Pap smear, respectively. The corresponding INBs given the threshold of $50,000 of WTP for annual Pap smear and vaccination program with annual HPV DNA testing followed by Pap smear were calculated as $ 435.9 and $339.0. Conclusion Compared with current practice (triennial Pap smear screening program), annual Pap smear or vaccination program with annual HPV DNA testing followed by Pap smear is the more cost-effectiveness strategies among all various preventive strategies.
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