Knowledge of breast cancer overdiagnosis changes attitudes toward treatment, screening

Jan 26th – There is great variation in how knowledge of breast cancer overdiagnosis affects patient attitudes about screening and treatment.

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Image: PD

1. There is great variation in how knowledge of breast cancer overdiagnosis affects patient attitudes about screening and treatment.

2. Many women viewed up to 30% risk of overdiagnosis as having little influence on screening and treatment attitudes.

Results of this study suggest that overdiagnosis should be included in physician-patient discussion about the benefits and potential risks of breast cancer screening. The perceived benefit of screening, whether overdiagnosis rates were 30% or 50%, differed considerably and highlights that patients consider higher rates of overdiagnosis acceptable as compared to physicians or public health officials. The complexity of how overdiagnosis might affect treatment decisions calls attention to the need for adequate patient education and careful, clear communication between patients and providers. Varying definitions of the prevalence of overdiagnosis, which range from 10-50%, complicate communication efforts.

To gain a more complete sense of the benefits of early detection, research is needed to determine whether screening reduces mortality rates and whether early-stage cancers can be categorized as invasive or non-invasive. To better understand risks, it will also be necessary to clarify the prevalence of overdiagnosis. This study was limited by its inability to account for women’s exposure to others’ experiences with breast cancer and its exclusion of women previously diagnosed with breast cancer. Having a friend or relative diagnosed and treated for breast cancer may affect women’s perception of overdiagnosis far more than any statistics provided, and perceptions may hinge on the outcome of the person’s treatment. Though study authors identified women by population-based sampling, it’s likely that women with greater interest in breast cancer screening and treatment were more apt to enroll. Notwithstanding, this study demonstrates the importance of soliciting patient preferences to map out the unexpected consequences of information provision.

Click to read the study in BMJ

Click to read an accompanying editorial in BMJ

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Image: PD

1. There is great variation in how knowledge of overdiagnosis affects women’s attitudes about screening and treatment.

2. Many women viewed up to 30% risk of overdiagnosis as having little influence on screening and treatment attitudes.

This [qualitative] study: examined how information about breast cancer overdiagnosis influenced the screening and treatment attitudes of 50 Australian women ages 40-79.

After an educational presentation, the majority of women were able to accurately define “overdetection” of breast cancer. When asked about early detection, most women considered a false positive rate of up to 30% acceptable but were uncomfortable with an overdiagnosis rate of 50%. Yet, even a 50% level of overdiagnosis did not deter some women from considering screening beneficial. Some women reported that overdiagnosis would affect their treatment attitudes more than their screening attitudes, such that they would prefer to continue screening as before but would be more likely to opt for watchful waiting or alternative therapies before pursuing aggressive treatments if diagnosed.

Further reading:

1. The benefits and harms of breast cancer screening: an independent review

2. Screening for breast cancer: U.S. Preventive Services Task Force recommendation statement

3. Effect of three decades of screening mammography on breast-cancer incidence

In sum: Results of this study suggest that overdiagnosis should be included in physician-patient discussion about the benefits and potential risks of breast cancer screening. The perceived benefit of screening, whether overdiagnosis rates were 30% or 50%, differed considerably and highlights that patients consider higher rates of overdiagnosis acceptable as compared to physicians or public health officials. The complexity of how overdiagnosis might affect treatment decisions calls attention to the need for adequate patient education and careful, clear communication between patients and providers. Varying definitions of the prevalence of overdiagnosis, which range from 10-50%, complicate communication efforts.

To gain a more complete sense of the benefits of early detection, research is needed to determine whether screening reduces mortality rates and whether early-stage cancers can be categorized as invasive or non-invasive. To better understand risks, it will also be necessary to clarify the prevalence of overdiagnosis. This study was limited by its inability to account for women’s exposure to others’ experiences with breast cancer and its exclusion of women previously diagnosed with breast cancer. Having a friend or relative diagnosed and treated for breast cancer may affect women’s perception of overdiagnosis far more than any statistics provided, and perceptions may hinge on the outcome of the person’s treatment. Though study authors identified women by population-based sampling, it’s likely that women with greater interest in breast cancer screening and treatment were more apt to enroll. Notwithstanding, this study demonstrates the importance of soliciting patient preferences to map out the unexpected consequences of information provision.

Click to read the study in BMJ

Click to read an accompanying editorial in BMJ

By [CH] and [LH]

More from this author: Pediatric providers who completed tobacco education program more likely to educate parental smokers about quitting, Minority of American children meet pediatric guidelines for both physical activity and screen-time viewing, Regional increases in unemployment in infancy associated with development of behavioral problems in American adolescents

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Caroline Huang: Caroline is a 3rd year Ph.D. candidate in Public Health at the University of Oxford’s Ethox Centre, where she is a Rhodes Scholar.

Leah Hawkins: Leah is a 5th year M.D./MPH candidate at Harvard Medical School.

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