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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

Average life expectancy extension in 40-to-74-year age group (vs. 50–74 years) in Japan and the United States; (a) absolute effect; (b) relative effecta. aRelative effect of average life expectancy extension was calculated; in Japan, eg, 26% [(63 − 50 = 13 days)/50 days × 100] (δ′ = 1.5δ).
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fig03: Average life expectancy extension in 40-to-74-year age group (vs. 50–74 years) in Japan and the United States; (a) absolute effect; (b) relative effecta. aRelative effect of average life expectancy extension was calculated; in Japan, eg, 26% [(63 − 50 = 13 days)/50 days × 100] (δ′ = 1.5δ).

Mentions: The effects of screening (eg, increases in life expectancies) were calculated for difference of δ′ (= 1.0δ–3.0δ) to test the sensitivity. There were considerable variations, but the screening strategy including women in their 40s remained optimal. Figure 3 shows the absolute effects compared with the relative effects of extended average life expectancy. Extended average life expectancy in the group aged 40–74 years (vs. 50–74 years) in δ′ = 1.5δ increased by 26% (13 days) and 22% (25 days) in Japan and the United States, respectively, under biennial screening conditions; however, the numbers of false-positive results increased 65% and 53% in Japan and the United States, respectively.


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)

Average life expectancy extension in 40-to-74-year age group (vs. 50–74 years) in Japan and the United States; (a) absolute effect; (b) relative effecta. aRelative effect of average life expectancy extension was calculated; in Japan, eg, 26% [(63 − 50 = 13 days)/50 days × 100] (δ′ = 1.5δ).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig03: Average life expectancy extension in 40-to-74-year age group (vs. 50–74 years) in Japan and the United States; (a) absolute effect; (b) relative effecta. aRelative effect of average life expectancy extension was calculated; in Japan, eg, 26% [(63 − 50 = 13 days)/50 days × 100] (δ′ = 1.5δ).
Mentions: The effects of screening (eg, increases in life expectancies) were calculated for difference of δ′ (= 1.0δ–3.0δ) to test the sensitivity. There were considerable variations, but the screening strategy including women in their 40s remained optimal. Figure 3 shows the absolute effects compared with the relative effects of extended average life expectancy. Extended average life expectancy in the group aged 40–74 years (vs. 50–74 years) in δ′ = 1.5δ increased by 26% (13 days) and 22% (25 days) in Japan and the United States, respectively, under biennial screening conditions; however, the numbers of false-positive results increased 65% and 53% in Japan and the United States, respectively.

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