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An analysis of mass screening strategies using a mathematical model: comparison of breast cancer screening in Japan and the United States.

Tsunematsu M, Kakehashi M - J Epidemiol (2014)

Bottom Line: Benefits (reduced number of deaths and extended average life expectancy) and harm (false-positives) associated with these strategies were calculated.The validity of including women in their 40s in Japan could not be determined without specifying the weight of harms compared to benefits.Whether screening of women in their 40s in Japan is justifiable must be carefully determined based the quantitative balance of benefits and harms.

View Article: PubMed Central - PubMed

Affiliation: Department of Health Informatics, Graduate School of Biomedical and Health Sciences Hiroshima University.

ABSTRACT

Background: Although the United States Preventive Services Task Force (USPSTF) downgraded their recommendation for breast cancer screening for women aged 40-49 years in 2009, Japanese women in their 40s have been encouraged to attend breast cancer screenings since 2004. The aim of this study is to examine whether these different mass-screening strategies are justifiable by the different situations of these countries and to provide evidence for suitable judgment.

Methods: Performance of screening strategies (annual/biennial intervals; initiating/terminating ages) was evaluated using a mathematical model based on the natural history of breast cancer and the transition between its stages. Benefits (reduced number of deaths and extended average life expectancy) and harm (false-positives) associated with these strategies were calculated.

Results: Additional average life expectancy by including women in their 40s as participants were 13 days (26%) and 25 days (22%) in Japan and the United States, respectively, under the biennial screening condition; however, the respective increases in numbers of false-positive cases were 65% and 53% in Japan and the United States. Moreover, the number of screenings needed to detect one diagnosis or to avert one death was smaller when participants were limited to women of age 50 or over than when women in their 40s were included. The validity of including women in their 40s in Japan could not be determined without specifying the weight of harms compared to benefits.

Conclusions: Whether screening of women in their 40s in Japan is justifiable must be carefully determined based the quantitative balance of benefits and harms.

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Related in: MedlinePlus

Model-predicted and observed statistics on age-specific incidence (a), mortality (b), and stage distribution of breast cancer (c) in Japan and the United States. A population of 100 000 women was traced from age 0 to 100 years. Observed statistics on incidencea peaked (154.5 per 100 000 women) in those age aged 45–49 years in Japan, whereas the incidence increased continuously from age 45 and peaked (433.1 per 100 000 women) in those aged 75–79 years in the United States. Observed statistics on mortality tended to increase with age in both Japan and the United States. Differences in mortality between Japan and the United States were marked in women aged 50 years or older. aExcluding carcinoma in situ.
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fig02: Model-predicted and observed statistics on age-specific incidence (a), mortality (b), and stage distribution of breast cancer (c) in Japan and the United States. A population of 100 000 women was traced from age 0 to 100 years. Observed statistics on incidencea peaked (154.5 per 100 000 women) in those age aged 45–49 years in Japan, whereas the incidence increased continuously from age 45 and peaked (433.1 per 100 000 women) in those aged 75–79 years in the United States. Observed statistics on mortality tended to increase with age in both Japan and the United States. Differences in mortality between Japan and the United States were marked in women aged 50 years or older. aExcluding carcinoma in situ.

Mentions: The total number of patients with breast cancer in Japan as predicted with this model was 6091. The incidence rates of breast cancer in Japan as calculated using the statistically reported incidence and as predicted with this model were 69.9 and 71.0 patients per 100 000 women, respectively (Figure 2-a1). The total number of breast cancer deaths in Japan as predicted with the model was 1425. The mortality rates of breast cancer as calculated using mortality statistics and as predicted with this model were 17.6 and 16.6 deaths per 100 000 women, respectively (Figure 2-b1). Therefore, this model seemed to have successfully predicted observed statistics. In contrast, the total number of patients with breast cancer in the United States as predicted with this model was 13 417. The incidence rates of breast in the Unites States cancer as calculated using incidence statistics and as predicted with this model were 165.4 and 167.8 patients per 100 000 women, respectively (Figure 2-a2). The total number of breast cancer deaths in the United States as predicted with this model was 3723. The breast cancer mortality rates as reported using mortality statistics and as predicted with this model were 35.3 and 46.6 deaths per 100 000 women, respectively (Figure 2-b2). Therefore, the model of this study seems to be less successful in a United States population, although the numerical gap between predicted and observed morality rates was relatively small for both countries. The distribution of disease stage as predicted with this model nearly coincided with that reported by observed statistics in both countries (Figures 2-c1, c2).


An analysis of mass screening strategies using a mathematical model: comparison of breast cancer screening in Japan and the United States.

Tsunematsu M, Kakehashi M - J Epidemiol (2014)

Model-predicted and observed statistics on age-specific incidence (a), mortality (b), and stage distribution of breast cancer (c) in Japan and the United States. A population of 100 000 women was traced from age 0 to 100 years. Observed statistics on incidencea peaked (154.5 per 100 000 women) in those age aged 45–49 years in Japan, whereas the incidence increased continuously from age 45 and peaked (433.1 per 100 000 women) in those aged 75–79 years in the United States. Observed statistics on mortality tended to increase with age in both Japan and the United States. Differences in mortality between Japan and the United States were marked in women aged 50 years or older. aExcluding carcinoma in situ.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4310878&req=5

fig02: Model-predicted and observed statistics on age-specific incidence (a), mortality (b), and stage distribution of breast cancer (c) in Japan and the United States. A population of 100 000 women was traced from age 0 to 100 years. Observed statistics on incidencea peaked (154.5 per 100 000 women) in those age aged 45–49 years in Japan, whereas the incidence increased continuously from age 45 and peaked (433.1 per 100 000 women) in those aged 75–79 years in the United States. Observed statistics on mortality tended to increase with age in both Japan and the United States. Differences in mortality between Japan and the United States were marked in women aged 50 years or older. aExcluding carcinoma in situ.
Mentions: The total number of patients with breast cancer in Japan as predicted with this model was 6091. The incidence rates of breast cancer in Japan as calculated using the statistically reported incidence and as predicted with this model were 69.9 and 71.0 patients per 100 000 women, respectively (Figure 2-a1). The total number of breast cancer deaths in Japan as predicted with the model was 1425. The mortality rates of breast cancer as calculated using mortality statistics and as predicted with this model were 17.6 and 16.6 deaths per 100 000 women, respectively (Figure 2-b1). Therefore, this model seemed to have successfully predicted observed statistics. In contrast, the total number of patients with breast cancer in the United States as predicted with this model was 13 417. The incidence rates of breast in the Unites States cancer as calculated using incidence statistics and as predicted with this model were 165.4 and 167.8 patients per 100 000 women, respectively (Figure 2-a2). The total number of breast cancer deaths in the United States as predicted with this model was 3723. The breast cancer mortality rates as reported using mortality statistics and as predicted with this model were 35.3 and 46.6 deaths per 100 000 women, respectively (Figure 2-b2). Therefore, the model of this study seems to be less successful in a United States population, although the numerical gap between predicted and observed morality rates was relatively small for both countries. The distribution of disease stage as predicted with this model nearly coincided with that reported by observed statistics in both countries (Figures 2-c1, c2).

Bottom Line: Benefits (reduced number of deaths and extended average life expectancy) and harm (false-positives) associated with these strategies were calculated.The validity of including women in their 40s in Japan could not be determined without specifying the weight of harms compared to benefits.Whether screening of women in their 40s in Japan is justifiable must be carefully determined based the quantitative balance of benefits and harms.

View Article: PubMed Central - PubMed

Affiliation: Department of Health Informatics, Graduate School of Biomedical and Health Sciences Hiroshima University.

ABSTRACT

Background: Although the United States Preventive Services Task Force (USPSTF) downgraded their recommendation for breast cancer screening for women aged 40-49 years in 2009, Japanese women in their 40s have been encouraged to attend breast cancer screenings since 2004. The aim of this study is to examine whether these different mass-screening strategies are justifiable by the different situations of these countries and to provide evidence for suitable judgment.

Methods: Performance of screening strategies (annual/biennial intervals; initiating/terminating ages) was evaluated using a mathematical model based on the natural history of breast cancer and the transition between its stages. Benefits (reduced number of deaths and extended average life expectancy) and harm (false-positives) associated with these strategies were calculated.

Results: Additional average life expectancy by including women in their 40s as participants were 13 days (26%) and 25 days (22%) in Japan and the United States, respectively, under the biennial screening condition; however, the respective increases in numbers of false-positive cases were 65% and 53% in Japan and the United States. Moreover, the number of screenings needed to detect one diagnosis or to avert one death was smaller when participants were limited to women of age 50 or over than when women in their 40s were included. The validity of including women in their 40s in Japan could not be determined without specifying the weight of harms compared to benefits.

Conclusions: Whether screening of women in their 40s in Japan is justifiable must be carefully determined based the quantitative balance of benefits and harms.

Show MeSH
Related in: MedlinePlus