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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

A mathematical model of breast cancer screening consisting of 12-month cycles of 10 health states that simulate the theoretical natural history of breast cancer, comprising the following seven structures: u1: healthy; w1: false positive; u2–u5: undetected breast cancer (stages 1–4); w2–w5: detected for breast cancer (stages 1–4) through screening or outpatient care; du1: died from a cause other than breast cancer; du2–du5a: undetected and died of breast cancer; dw1–dw4a: detected and died of breast cancer. Stage classifications used here are those published by the Union for International Cancer Control (UICC) for Japanese data and by the American Joint Committee on Cancer (AJCC) for United States data. aDeath from causes other than breast cancer (μ) is excluded. BC, breast cancer.
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fig01: A mathematical model of breast cancer screening consisting of 12-month cycles of 10 health states that simulate the theoretical natural history of breast cancer, comprising the following seven structures: u1: healthy; w1: false positive; u2–u5: undetected breast cancer (stages 1–4); w2–w5: detected for breast cancer (stages 1–4) through screening or outpatient care; du1: died from a cause other than breast cancer; du2–du5a: undetected and died of breast cancer; dw1–dw4a: detected and died of breast cancer. Stage classifications used here are those published by the Union for International Cancer Control (UICC) for Japanese data and by the American Joint Committee on Cancer (AJCC) for United States data. aDeath from causes other than breast cancer (μ) is excluded. BC, breast cancer.

Mentions: Analyses were carried out using a mathematical model of mass screening and were performed with Mathematica 8.0 computational software (Wolfram Research, Champaign, IL, USA). The basic structure of the model is shown in Figure 1. In this model, based on the natural history of breast cancer, the number of women of each age specified by stage of breast cancer was calculated year by year. The number of women with breast cancer was also specified by treatment status (detected or undetected). Women with detected breast cancer were considered to be on treatment, while women with undetected breast cancer were deemed not on treatment. Women become one year older each year and subsequently may develop breast cancer. The transition rate from one stage to the next is summarized in Table 1.21–36 Rates at which women die of breast cancer or from other causes according to mortality rates were obtained from Vital Statistics.26–29 Incidence rates were also obtained from population-based cancer registries.21,22 Incidence rates of breasts cancer in women of each age were calculated by the conversion of data from a 5-year age classification.


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)

A mathematical model of breast cancer screening consisting of 12-month cycles of 10 health states that simulate the theoretical natural history of breast cancer, comprising the following seven structures: u1: healthy; w1: false positive; u2–u5: undetected breast cancer (stages 1–4); w2–w5: detected for breast cancer (stages 1–4) through screening or outpatient care; du1: died from a cause other than breast cancer; du2–du5a: undetected and died of breast cancer; dw1–dw4a: detected and died of breast cancer. Stage classifications used here are those published by the Union for International Cancer Control (UICC) for Japanese data and by the American Joint Committee on Cancer (AJCC) for United States data. aDeath from causes other than breast cancer (μ) is excluded. BC, breast cancer.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig01: A mathematical model of breast cancer screening consisting of 12-month cycles of 10 health states that simulate the theoretical natural history of breast cancer, comprising the following seven structures: u1: healthy; w1: false positive; u2–u5: undetected breast cancer (stages 1–4); w2–w5: detected for breast cancer (stages 1–4) through screening or outpatient care; du1: died from a cause other than breast cancer; du2–du5a: undetected and died of breast cancer; dw1–dw4a: detected and died of breast cancer. Stage classifications used here are those published by the Union for International Cancer Control (UICC) for Japanese data and by the American Joint Committee on Cancer (AJCC) for United States data. aDeath from causes other than breast cancer (μ) is excluded. BC, breast cancer.
Mentions: Analyses were carried out using a mathematical model of mass screening and were performed with Mathematica 8.0 computational software (Wolfram Research, Champaign, IL, USA). The basic structure of the model is shown in Figure 1. In this model, based on the natural history of breast cancer, the number of women of each age specified by stage of breast cancer was calculated year by year. The number of women with breast cancer was also specified by treatment status (detected or undetected). Women with detected breast cancer were considered to be on treatment, while women with undetected breast cancer were deemed not on treatment. Women become one year older each year and subsequently may develop breast cancer. The transition rate from one stage to the next is summarized in Table 1.21–36 Rates at which women die of breast cancer or from other causes according to mortality rates were obtained from Vital Statistics.26–29 Incidence rates were also obtained from population-based cancer registries.21,22 Incidence rates of breasts cancer in women of each age were calculated by the conversion of data from a 5-year age classification.

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