Guido Van Schoor | Radboud University Nijmegen (original) (raw)

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Papers by Guido Van Schoor

Journal of medical screening, 2012

The European Journal of Public Health, 2012

19 Brenner H, Gefeller O, Hakulinen T. Period analysis for 'up-to-date' cancer survival data: the... more 19 Brenner H, Gefeller O, Hakulinen T. Period analysis for 'up-to-date' cancer survival data: theory, empirical evaluation, computational realisation and applications. Eur J Cancer 2004;40:326-35. 20 Regidor E. Measures of health inequalities: part 2. J Epidemiol Community Health 2004;58:900-3. 21 Woods L, Rachet B, Coleman MP. Choice of geographic unit influence socioeconomic inequalities in breast cancer survival. Br J Cancer 2005;92:1279-82. 22 Dailey AB, Kasl SV, Holford TR, et al. Neighborhood-level socioeconomic predictors of nonadherence to mammography screening guidelines. Cancer Epidemiol Biomarkers Prev 2007;16:2293-303. 23 Bonfill Cosp X, Marzo Castillejo M, Pladevall Vila M, et al. Strategies for increasing women participation in community breast cancer screening. Cochrane Database Syst Rev 2001;1:D002943. 24 Jepson R, Clegg A, Forbes C, et al. The determinants of screening uptake and interventions for increasing uptake: a systematic review. Health Technol Assess 2000;4:1-133. 25 Han H, Lee J, Kim J, et al. A meta-analysis of interventions to promote mammography among ethnic minority women. Nurs Res 2009;58:246-54. 26 Legler J, Meissner H, Coyne C, et al. The effectiveness of interventions to promote mammography among women with historically lower rates of screening.

European Journal of Epidemiology, 2011

Residual confounding, after adjustment for age, is the major criticism of observational studies o... more Residual confounding, after adjustment for age, is the major criticism of observational studies on breast cancer screening effectiveness. We developed realistic scenarios for the prevalence and strength of risk factors on screened and not screened groups, and explored the impact of residual confounding bias. Our results demonstrate that residual confounding bias is a minor issue in screening programme evaluations.

European Journal of Cancer, 2008

A large increase in the incidence of breast cancer has been observed in many countries over the l... more A large increase in the incidence of breast cancer has been observed in many countries over the last two decades. On the other hand, however, breast cancer mortality has decreased. The prominent burden of breast cancer in the female population induces a lot of discussion about incidence and mortality rates, whereas lifetime risks are less mentioned. This study provides information on the changes in risks for Dutch women with regards to being diagnosed with breast cancer (both invasive and in situ) or dying from this disease during the screening era.

European Journal of Cancer, 2010

The United Kingdom is currently moving the age limit for invitation in its national breast screen... more The United Kingdom is currently moving the age limit for invitation in its national breast screening programme downwards from 50 to 47. In contrast, the US Preventive Services Task Force concluded that, because of borderline statistical significance on effectiveness of mammographic screening, the current evidence is insufficient to advise screening in women aged 40-49. We designed a case-referent study to investigate the effect of biennial mammographic screening on breast cancer mortality for women in their forties. In Nijmegen, the Netherlands, screening started in 1975. A total of 272 breast cancer deaths were identified, and 1360 referents aged 40-69 were sampled from the population invited for screening. Effectiveness was estimated by calculating the odds ratio (OR) indicating the breast cancer death rate in screened versus unscreened women. In women aged 40-49, the effect of screening was OR = 0.50 (95% confidence interval (CI) = 0.30-0.82). This result is similar to those aged 50-59 (OR = 0.54; 95% CI = 0.35-0.85) and 60-69 (OR = 0.65; 95% CI = 0.38-1.13). Our results add convincing evidence about the effectiveness of biennial mammographic screening in women aged 40-49.

European Addiction Research, 2008

This study examined whether personality traits and peer drinking affect alcohol consumption in yo... more This study examined whether personality traits and peer drinking affect alcohol consumption in young adults. Data were analyzed from a study that was conducted in a &amp;amp;amp;amp;amp;amp;amp;#39;bar laboratory&amp;amp;amp;amp;amp;amp;amp;#39; in which ad-lib drinking of peer groups was observed. The findings indicate that extroversion is moderately associated with self-reported daily drinking, while low emotional stability is modestly associated with alcohol-related problems. With regard to drinking in the observational drinking setting, personality is not associated with young adults&amp;amp;amp;amp;amp;amp;amp;#39; actual alcohol consumption. Further, peer drinking levels were strongly related to young adults&amp;amp;amp;amp;amp;amp;amp;#39; drinking. Besides, agreeableness interacted with the effects of peer drinking on young adults&amp;amp;amp;amp;amp;amp;amp;#39; drinking in such a way that agreeable individuals adapted their actual alcohol consumption more easily than others when socializing in a high- or a low-drinking peer group. We concluded that drinking in a peer context, irrespective of personality, played a major role in forming young adults&amp;amp;amp;amp;amp;amp;amp;#39; drinking. However, personality (i.e. agreeableness) definitely played a role to the extent of the individuals&amp;amp;amp;amp;amp;amp;amp;#39; adaptation to peer drinking norms.

Cancer Causes & Control, 2010

We designed a case-referent study to investigate the effect of mammographic screening at the indi... more We designed a case-referent study to investigate the effect of mammographic screening at the individual level, looking at the association of breast cancer death with screening history. The study population included all women aged 50-75 in the province of Limburg, the Netherlands who had been invited to the screening program from 1989 to 2006. From this population, 118 cases originated who died of breast cancer in 2004 or 2005. The screening history of these cases was collected and compared with a sample of the invited population. The breast cancer death rate in the screened relative to the unscreened women was estimated as the odds ratio (OR). This OR was adjusted for self-selection bias, the difference in baseline risk for breast cancer death between screened and unscreened women. Analysis of the data showed a breast cancer mortality reduction of 70% in the screened versus the unscreened women (OR = 0.30, 95% CI 0.14-0.63). The magnitude of self-selection was estimated specifically for Limburg. After correction for self-selection bias, the effect of screening increased to 76% (OR = 0.24, 95% CI 0.10-0.58). Screening resulted in a remarkable reduction in breast cancer mortality. Contrary to findings in other countries, adjustment for self-selection in Limburg had no influence on the impact of screening. Thanks to a well-organized centralized screening program, similar results are expected in other regions of the Netherlands.

Breast Diseases: A Year Book Quarterly, 2012

BACKGROUND: Favourable outcomes of breast cancer screening trials in the 1970s and 1980s resulted... more BACKGROUND: Favourable outcomes of breast cancer screening trials in the 1970s and 1980s resulted in the launch of populationbased service screening programmes in many Western countries. We investigated whether improvements in mammography and treatment modalities have had an influence on the effectiveness of breast cancer screening from 1975 to 2008. METHODS: In Nijmegen, the Netherlands, 55 529 women received an invitation for screening between 1975 and 2008. We designed a case -referent study to evaluate the impact of mammographic screening on breast cancer mortality over time from 1975 to 2008. A total number of 282 breast cancer deaths were identified, and 1410 referents aged 50 -69 were sampled from the population invited for screening. We estimated the effectiveness by calculating the odds ratio (OR) indicating the breast cancer death rate for screened vs unscreened women. RESULTS: The breast cancer death rate in the screened group over the complete period was 35% lower than in the unscreened group (OR ¼ 0.65; 95% CI ¼ 0.49 -0.87). Analysis by calendar year showed an increasing effectiveness from a 28% reduction in breast cancer mortality in the period 1975 -1991 (OR ¼ 0.72; 95% CI ¼ 0.47 -1.09) to 65% in the period 1992 -2008 (OR ¼ 0.35; 95% CI ¼ 0.19 -0.64). CONCLUSION: Our results show an increasingly strong reduction in breast cancer mortality over time because of mammographic screening.

Journal of medical screening, Jan 21, 2014

To provide proof of concept for a simple model to estimate the stage shift as a result of breast ... more To provide proof of concept for a simple model to estimate the stage shift as a result of breast cancer screening in low- and middle-income countries (LMICs). Stage shift is an essential early detection indicator and an important proxy for the performance and possible further impact of screening programmes. Our model could help LIMCs to choose appropriate control strategies. We assessed our model concept in three steps. First, we calculated the proportional performance rates (i.e. index number Z) based on 16 screening rounds of the Nijmegen Screening Program (384,884 screened women). Second, we used linear regression to assess the association between Z and the amount of stage shift observed in the programme. Third, we hypothesized how Z could be used to estimate the stage shift as a result of breast cancer screening in LMICs. Stage shifts can be estimated by the proportional performance rates (Zs) using linear regression. Zs calculated for each screening round are highly associated ...