Publications (14)44.52 Total impact
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Article: Liquid-based cervical cytology using ThinPrep technology: weighing the pros and cons in a cost-effectiveness analysis.
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ABSTRACT: Cervical cancer screening with liquid-based cytology (LBC) has been developed as an alternative to the conventional Papanicolaou (CP) smear. Cost-effectiveness is one of the issues when evaluating LBC. Based on the results of a Dutch randomised controlled trial, we conducted cost-effectiveness threshold analyses to investigate under what circumstances manually screened ThinPrep LBC is cost-effective for screening. The MISCAN-Cervix microsimulation model and data from the Dutch NETHCON trial (including 89,784 women) were used to estimate the costs and (quality-adjusted) life years ((QA)LYs) gained for EU screening schedules, varying cost-effectiveness threshold values. Screening strategies were primary cytological screening with LBC or CP, and triage with human papillomavirus (HPV) testing. Threshold analyses showed that screening with LBC as a primary test can be cost-effective if LBC is less than 3.2 more costly per test than CP, if the sensitivity of LBC is at least 3-5 % points higher than CP, if the quality of life for women in triage follow-up is only 0.39, or if the rate of inadequate CP smears is at least 16.2 %. Regarding test characteristics and costs of LBC and CP, only under certain conditions will a change from CP to manually screened ThinPrep LBC be cost-effective. If none of these conditions are met, implementation of manually screened ThinPrep LBC seems warranted only if there are advantages other than cost-effectiveness. Further research is needed to establish whether other LBC systems will be more favorable with regard to cost-effectiveness.Cancer Causes and Control 06/2012; 23(8):1323-31. · 2.88 Impact Factor -
Article: Primary screening for human papillomavirus compared with cytology screening for cervical cancer in European settings: cost effectiveness analysis based on a Dutch microsimulation model.
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ABSTRACT: To investigate, using a Dutch model, whether and under what variables framed for other European countries screening for human papillomavirus (HPV) is preferred over cytology screening for cervical cancer, and to calculate the preferred number of examinations over a woman's lifetime. Cost effectiveness analysis based on a Dutch simulation model. Base case analyses investigated the cost effectiveness of more than 1500 different screening policies using the microsimulation model. Subsequently, the policies were compared for five different scenarios that represent different possible scenarios (risk of cervical cancer, previous screening, quality associated test characteristics, costs of testing, and prevalence of HPV). Various European countries. Unvaccinated women born between 1939 and 1992. Optimal screening strategy in terms of incremental cost effectiveness ratios (costs per quality adjusted life years gained) compared with different cost effectiveness thresholds, for two levels of sensitivity and costs of the HPV test. Primary HPV screening was the preferred primary test over the age of 30 in many considered scenarios. Primary cytology screening was preferred only in scenarios with low costs of cytology and in scenarios with a high prevalence of HPV in combination with high costs of HPV testing. Most European countries should consider switching from primary cytology to HPV screening for cervical cancer. HPV screening must, however, only be implemented in situations where screening is well controlled.BMJ (Clinical research ed.). 01/2012; 344:e670. -
Article: Practical implications of differential discounting in cost-effectiveness analyses with varying numbers of cohorts.
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ABSTRACT: To call attention to the influence of the number of birth-cohorts used in cost-effectiveness analysis (CEA) models on incremental cost-effectiveness ratios (ICERs) under differential discounting. The consequences of increasing the number of birth-cohorts are demonstrated using a CEA of cervical cancer prevention as an example. The cost-effectiveness of vaccinating 12-year-old girls against the human papillomavirus is estimated with the MISCAN microsimulation screening analysis model for 1, 10, 20, and 30 birth-cohorts. Costs and health effects are discounted with equal rates of 4% and alternatively with differential rates of 4% and 1.5% respectively. The effects of increasing the number of cohorts are shown by comparing the ICERs under equal and differential discounting. The ICER decreases as the number of cohorts increases under differential discounting, but not under equal discounting. The variation of ICERs with the number of cohorts under differential discounting prompts questions regarding the appropriate specification of CEA models and interpretation of their results. In particular, it raises concerns that arbitrary variation in study specification leads to arbitrary variation in results. Such variations could lead to erroneous policy decisions. These findings are relevant to CEA guidance authorities, CEA practitioners, and decision makers. Our results do not imply a problem with differential discounting per se, yet they highlight the need for practical guidance for its use.Value in Health 06/2011; 14(4):438-42. · 2.19 Impact Factor -
Article: Trends in cervical cancer in the Netherlands until 2007: has the bottom been reached?
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ABSTRACT: We explored trends in incidence and mortality of cervical cancer by age, stage and morphology, and linked the observed trends to screening activities. Data was retrieved from the Netherlands Cancer Registry during 1989-2007 (incidence) and Statistics Netherlands during 1970-2007 (mortality). Trends were evaluated by calculating the estimated annual percentage change (EAPC). Joinpoint regression analysis was used to detect changes in trends. Cervical intraepithelial neoplasia (CIN) detection rates were calculated by data from "the nationwide network and registry of histo- and cytopathology" during 1990-2006. Total age-adjusted incidence rate (European standardized rate (ESR)) was 7.9 per 100,000 woman years in 2007. During 1989-1998, incidence rates decreased with an EAPC of -1.3% (95% confidence interval (CI) -2.2 to -0.3), during 1998-2001 with -6.7% (95% CI: -16.4 to 4.1), and increased during 2001-2007 with 2.3% (95% CI: 0.4 to 4.2). Total mortality ESR was 1.9 per 100,000 woman years in 2007. Mortality rates decreased during 1970-1994 annually with -4.1% (95% CI: -4.6% to -3.7%), and with -2.6% (95% CI: -3.8% to -1.5%) during 1994-2007. The observed trend in total incidence is similar to the trend in squamous cell carcinomas in age group 35-54 years, suggesting that the observed trends are likely to be associated to changes in the screening program. This is supported by the trend in CINIII detection rates. In conclusion, incidence and mortality overall decreased and leveled off. On top of that there was an extra decrease that was compensated by a following recent increase in incidence, probably resulting from reorganization of the Dutch screening program.International Journal of Cancer 05/2011; 128(9):2174-81. · 5.44 Impact Factor -
Article: Would the effect of HPV vaccination on non-cervical HPV-positive cancers make the difference for its cost-effectiveness?
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ABSTRACT: Besides cervical cancer, the human papillomavirus (HPV) is found in other cancers and may be preventable with HPV vaccination. However, these other cancers are often not accounted for in cost-effectiveness analyses of HPV vaccination. This study estimates the potential maximum effect on the cost-effectiveness ratio (CER) of HPV vaccination in preventing non-cervical HPV-positive cancers. For the Dutch situation, a mathematical equation was used to estimate the maximum impact if all cancer cases of the penis, vulva/vagina, anus, oral cavity and oro-pharynx with HPV16/18 are prevented, in terms of number of life years gained, savings and improvement in the CER of the vaccination. For other countries and for future developments, we show how the impact on the CER varies depending on the incidence of cervical/non-cervical HPV 16/18-positive cancers, vaccine costs and clinical costs. If in the Netherlands all HPV 16/18-positive cancers are prevented by vaccination in women only, compared to if only HPV 16/18-positive cervical cancer is prevented, the life years gained increase with 14%, the savings increase with 18%, and the CER decreases with 13%. If vaccination prevents HPV-positive cancers in both men and women, these figures increase to 25%, 26% and 21%, respectively. In conclusion, if HPV vaccination fully prevents all non-cervical HPV-positive cancers, this would substantially increase its cost-effectiveness. The impact of the vaccination varies depending on the incidence of cervical/non-cervical HPV16/18-positive cancers, the vaccine costs and clinical costs. Observed combinations of these parameters in different countries show a decrease in the CER between 10% and 31%.European journal of cancer (Oxford, England: 1990) 10/2010; 47(3):428-35. · 4.12 Impact Factor -
Article: [Unequal discounting of health care costs and effects causes confusion].
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ABSTRACT: Discounting is a widely accepted practice in cost-effectiveness analysis to weigh future costs and effects for their timing. In 2006, the Dutch Health Care Insurance Board revised its recommended rates for discounting. They recommended differential discounting of costs and effects, whereby effects are discounted at a lower rate relative to the costs. The question is whether this guideline is to be generally used for decision-making in the Netherlands. We show how the use of unequal discount rates leads to confusing cost-effectiveness results and why further implementation guidelines are essential.Nederlands tijdschrift voor geneeskunde 01/2010; 154:A1970. -
Article: The challenges of organising cervical screening programmes in the 15 old member states of the European Union.
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ABSTRACT: Cervical cancer incidence and mortality can be reduced substantially by organised cytological screening at 3 to 5 year intervals, as was demonstrated in the Nordic countries, the United Kingdom, the Netherlands and parts of Italy. Opportunistic screening, often proposed at yearly schedules, has also reduced the burden of cervical cancer in some, but not all, of the other old member states (belonging to the European Union since 1995) but at a cost that is several times greater. Well organised screening programmes have the potential to achieve greater participation of the target population at regular intervals, equity of access and high quality. Despite the consistent evidence that organised screening is more efficient than non-organised screening, and in spite of the Cancer Screening Recommendations of the European Council, health authorities of eight old member states (Austria, Belgium, France, Germany, Greece, Luxembourg, Portugal and Spain) have not yet started national organised implementation of screening for cervical cancer. A decision was made by the Irish government to extend their pilot programme nationally while new regional programmes commenced in Portugal and Spain. Introduction of new methods of prevention, such as HPV screening and prophylactic HPV vaccination, can reduce the burden further, but this will require a high level of organisation with particular attention needed for the maximisation of population coverage, compliance with evidence-based guidelines, monitoring of data enabling continued evaluation and improvement of the preventive programmes.European journal of cancer (Oxford, England: 1990) 09/2009; 45(15):2671-8. · 4.12 Impact Factor -
Article: Cost-effectiveness analysis of human papillomavirus vaccination in the Netherlands.
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ABSTRACT: In the Netherlands, low cervical cancer incidence and mortality rates might limit the cost-effectiveness of vaccination against the human papillomavirus (HPV). We examined the effect on cervical cancer incidence and mortality of adding HPV vaccination to the current Dutch cervical cancer screening situation and calculated the cost-effectiveness. Costs and effects were estimated under favorable assumptions (ie, that HPV vaccination provides lifelong protection against 70% of all cervical cancers, has no side effects, and is administered to all women regardless of their risk of cervical cancer) by using the microsimulation screening analysis (MISCAN) model. The impact of changes in the price of vaccination, number of booster vaccinations, vaccination attendance rate, vaccination efficacy, cervical cancer incidence level, and quality-of-life assumptions was investigated in sensitivity analyses. Using the current price of euro118 per vaccine dose and with discounting of costs and effects at an annual rate of 3%, adding HPV vaccination to the current Dutch screening situation had a cost-effectiveness ratio of euro53 500 per quality-adjusted life-year (QALY) gained. The threshold price per vaccine dose at which the cost-effectiveness of vaccination would correspond to an acceptability threshold of euro20 000 per QALY gained was euro40. With the addition of one or more (up to four) booster vaccinations during a lifetime, this threshold price decreased to euro33 for one booster (to euro16 for four boosters). With a doubling of the cervical cancer incidence level, the cost-effectiveness ratio was euro24 400 per QALY gained and the maximum price per dose at threshold of euro20 000 was euro97. All threshold prices were lower under less favorable effectiveness assumptions. In the Netherlands, HPV vaccination is not cost-effective even under favorable assumptions. To become cost-effective, the vaccine price would have to be decreased considerably, depending on the effectiveness of the vaccine.CancerSpectrum Knowledge Environment 08/2009; 101(15):1083-92. · 14.07 Impact Factor -
Article: [In Process Citation]
Nederlands tijdschrift voor geneeskunde 05/2009; 153(16):754-8. -
Article: Gender differences in the trend of colorectal cancer incidence in Singapore, 1968-2002.
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ABSTRACT: Over the past decades, incidence trends of colorectal cancer are sharply increased in Singapore. In this population-based study we describe changes in colorectal cancer incidence in Singapore and explore the reasons behind these changes through age-period cohort (APC) modeling. We included all 22,609 colorectal cancer cases reported to the Singapore Cancer Registry between 1968 and 2002. Poisson regression, using age-period (AP) and age-cohort (AC) models was used to determine the effects of age at diagnosis, calendar period, and birth cohort. Male colorectal cancer rates between 1968 and 2002 from 20 to 40 per 100,000 person years. The increase was sharpest among older men, for whom there was a significant AC effect. Female colorectal cancer rates increased until 1992 (from 16 to 29 per 100,000 person years) and stabilized afterward. For women under 65 years, we observed a significant AP effect, corresponding to a sudden rise in colorectal cancer incidence around 1978. This study demonstrates important gender differences in colorectal cancer incidence in Singapore, with increasing rates among men, and stabilized rates in women. The increase in men is mainly attributable to an incidence increase in the oldest age groups, probably due to increased exposure to dietary and lifestyle risk factors earlier in life. The stabilization in female colorectal cancer risk could be due to lower exposure to lifestyle risk factors and prophylactic removal of precancerous lesions.International Journal of Colorectal Disease 06/2008; 23(5):461-7. · 2.38 Impact Factor -
Article: Does lowering the screening age for cervical cancer in The Netherlands make sense?
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ABSTRACT: Recommendations for the age to initiate cervical cancer screening should be directed towards maximum detection of early cervical cancer. However, the screening programme should do more good than harm. The aim of this analysis was to determine whether the target age for cervical cancer screening should be lowered in view of apparent increases in new cases of invasive cancer below age 30 and in age group 30-44 years in The Netherlands. Therefore, all cervical cancer cases diagnosed between January 1, 1989 and December 31, 2003 were selected from the nationwide population-based Netherlands Cancer Registry. For age group 25-39 years, incidence data were also available for 2004 and 2005. To describe trends, the estimated annual percentage of change and joinpoint analysis were used. Between ages 25 and 28 years, the absolute number of new cases of cervical cancer annually has varied between 0 and 9 per age. Significantly decreasing trends in incidence were observed for age groups 35-39 and 45-49 (p < 0.0001 and p = 0.01, respectively). The annual number of deaths fluctuated with a decreasing trend for age groups 30-34 and 35-39 years (p = 0.01 and p = 0.03, respectively). Because the incidence and mortality rates for cervical cancer among women younger than 30 are low and not increasing, lowering the age for cervical cancer screening is not useful at this time. Although the number of years of life gained is high for every case of cervical cancer prevented, the disadvantages of lowering the screening age would be very large and even become disproportionate compared to the potential advantages.International Journal of Cancer 06/2008; 123(6):1403-6. · 5.44 Impact Factor -
Article: Childhood social class and cancer incidence: results of the globe study.
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ABSTRACT: Despite increased recognition of the importance of investigating socio-economic inequalities in health from a life course perspective, little is known about the influence of childhood socio-economic position (SEP) on cancer incidence. The authors studied the association between father's occupation and adult cancer incidence by linking information from the longitudinal GLOBE study with the regional population-based Eindhoven Cancer Registry (the Netherlands) over a period of 14 years. In 1991, 18,973 participants (response rate 70.1%) of this study responded to a postal questionnaire, including questions on SEP in youth and adulthood. Respondents above the age of 24 were included (N=12,978). Cox regression was used to calculate hazard ratios (HR) for all cancers as well as for the five most frequently occurring cancers by respondent's educational level or occupational class, and by father's occupational class (adjusted for respondent's education and occupation). Respondents with a low educational level showed an increased risk of all cancers, lung and breast cancer (in women). Respondents with a low adult occupational level showed an increased risk of lung cancer and a reduced risk of basal cell carcinoma. After adjustment for adult education and occupation, respondents whose father was in a lower occupational class showed an increased risk of colorectal cancer as compared to those with a father in the highest social class. In contrast, respondents whose father was in a lower occupational class, showed a decreased risk of basal cell carcinoma as compared to those with a father in the highest occupational class. The association between childhood SEP and cancer incidence is less consistent than the association between adult SEP and cancer incidence, but may exist for colorectal cancer and basal cell carcinoma.Social Science [?] Medicine 04/2008; 66(5):1131-9. · 2.70 Impact Factor -
Article: Risk factors for otitis media: an international perspective.
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ABSTRACT: Opinions about otitis media (OM) as an illness and about the need for antibiotic or surgical treatment vary internationally. It is not known how this is to be explained, whether by cultural differences or by other factors, such as variation in environmental risk factors for OM. To report on variation in environmental risk factors for OM across Western countries, and on the organisation of health care in these countries. Main environmental risk factors for OM were identified by searching Pubmed. Data on the distribution of these risk factors and the organisation of health care across countries were obtained from the OECD and WHO websites. Main risk factors for OM were day-care, number of siblings, smoking, breastfeeding, birth weight, socio-economic status (SES) and air pollution. Data were available for several European countries, the United State, Canada and Australia. Large international differences were found regarding the proportion of children attending day-care (Sweden 75% versus Italy 6%) and being breastfed at age 6 months (Norway 80% versus Poland 6%), and the rate of female smokers (Germany, France and Norway 30-40% versus Portugal <10%). It appears that differences in risk factor exposure between populations are often overshadowed by other culturally or demographically significant factors. Attempts to discern these factors within populations and between countries may be important in the management of OM and warrants further study.International Journal of Pediatric Otorhinolaryngology 08/2006; 70(7):1251-6. · 1.17 Impact Factor -
Article: Risk factors for otitis media: An international perspective
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ABSTRACT: BackgroundOpinions about otitis media (OM) as an illness and about the need for antibiotic or surgical treatment vary internationally. It is not known how this is to be explained, whether by cultural differences or by other factors, such as variation in environmental risk factors for OM.ObjectivesTo report on variation in environmental risk factors for OM across Western countries, and on the organisation of health care in these countries.MethodsMain environmental risk factors for OM were identified by searching Pubmed. Data on the distribution of these risk factors and the organisation of health care across countries were obtained from the OECD and WHO websites.ResultsMain risk factors for OM were day-care, number of siblings, smoking, breastfeeding, birth weight, socio-economic status (SES) and air pollution. Data were available for several European countries, the United State, Canada and Australia. Large international differences were found regarding the proportion of children attending day-care (Sweden 75% versus Italy 6%) and being breastfed at age 6 months (Norway 80% versus Poland 6%), and the rate of female smokers (Germany, France and Norway 30–40% versus Portugal <10%).ConclusionIt appears that differences in risk factor exposure between populations are often overshadowed by other culturally or demographically significant factors. Attempts to discern these factors within populations and between countries may be important in the management of OM and warrants further study.International Journal of Pediatric Otorhinolaryngology.
Top co-authors
Top Journals
Institutions
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2008–2012
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Erasmus MC
- Research Group for Public Health
Rotterdam, South Holland, Netherlands -
National University of Singapore
- Centre for Molecular Epidemiology
Singapore, Singapore
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2008–2011
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Erasmus Universiteit Rotterdam
- Department of Public Health (MGZ)
Rotterdam, South Holland, Netherlands
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2009
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Integraal Kankercentrum Nederland
Amsterdam, North Holland, Netherlands
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