Meta-analysis of breast cancer mortality benefit and overdiagnosis adjusted for adherence: improving information on the effects of attending screening mammography

Surrogate endpoint metaregression: useful statistics for regulators and trialists

OBJECTIVES

The main purpose of using a surrogate endpoint is to estimate the treatment effect on the true endpoint sooner than with a true endpoint. Based on a metaregression of historical randomized trials with surrogate and true endpoints, we discuss statistics for applying and evaluating surrogate endpoints.

METHODS

We computed statistics from 2 types of linear metaregressions for trial-level data: simple random effects and novel random effects with correlations among estimated treatment effects in trials with more than 2 arms. A key statistic is the estimated intercept of the metaregression line. An intercept that is small or not statistically significant increases confidence when extrapolating to a new treatment because of consistency with a single causal pathway and invariance to labeling of treatments as controls. For a regulator applying the metaregression to a new treatment, a useful statistic is the 95% prediction interval. For a clinical trialist planning a trial of a new treatment, useful statistics are the surrogate threshold effect proportion, the sample size multiplier adjusted for dropouts, and the novel true endpoint advantage.

RESULTS

We illustrate these statistics with surrogate endpoint metaregressions involving antihypertension treatment, breast cancer screening, and colorectal cancer treatment.

CONCLUSION

Regulators and trialists should consider using these statistics when applying and evaluating surrogate endpoints.

Data-driven overdiagnosis definitions: A scoping review

INTRODUCTION

Adequate methods to promptly translate digital health innovations for improved patient care are essential. Advances in Artificial Intelligence (AI) and Machine Learning (ML) have been sources of digital innovation and hold the promise to revolutionize the way we treat, manage and diagnose patients. Understanding the benefits but also the potential adverse effects of digital health innovations, particularly when these are made available or applied on healthier segments of the population is essential. One of such adverse effects is overdiagnosis.

OBJECTIVE

to comprehensively analyze quantification strategies and data-driven definitions for overdiagnosis reported in the literature.

METHODS

we conducted a scoping systematic review of manuscripts describing quantitative methods to estimate the proportion of overdiagnosed patients.

RESULTS

we identified 46 studies that met our inclusion criteria. They covered a variety of clinical conditions, primarily breast and prostate cancer. Methods to quantify overdiagnosis included both prospective and retrospective methods including randomized clinical trials, and simulations.

CONCLUSION

a variety of methods to quantify overdiagnosis have been published, producing widely diverging results. A standard method to quantify overdiagnosis is needed to allow its mitigation during the rapidly increasing development of new digital diagnostic tools.

Overdiagnosis Due to Screening Mammography for Breast Cancer among Women Aged 40 Years and Over: A Systematic Review and Meta-Analysis

The current systematic review and meta-analysis was conducted to estimate the incidence of overdiagnosis due to screening mammography for breast cancer among women aged 40 years and older. A PRISMA systematic search appraisal and meta-analysis were conducted. A systematic literature search of English publications in PubMed, Web of Science, EMBASE, Scopus, and Google Scholar was conducted without regard to the region or time period. Generic, methodological, and statistical data were extracted from the eligible studies. A meta-analysis was completed by utilizing comprehensive meta-analysis software. The effect size estimates were calculated using the fail-safe N test. The funnel plot and the Begg and Mazumdar rank correlation tests were employed to find any potential bias among the included articles. The strength of the association between two variables was assessed using Kendall’s tau. Heterogeneity was measured using the I-squared (I2) test. The literature search in the five databases yielded a total of 4214 studies. Of those, 30 articles were included in the final analysis, with sample sizes ranging from 451 to 1,429,890 women. The vast majority of the articles were retrospective cohort designs (24 articles). The age of the recruited women ranged between 40 and 89 years old. The incidence of overdiagnosis due to screening mammography for breast cancer among women aged 40 years and older was 12.6%. There was high heterogeneity among the study articles (I2 = 99.993), and the pooled event rate was 0.126 (95% CI: 15 0.101–0.156). Despite the random-effects meta-analysis showing a high degree of heterogeneity among the articles, the screening tests have to allow for a certain degree of overdiagnosis (12.6%) due to screening mammography for breast cancer among women aged 40 years and older. Furthermore, efforts should be directed toward controlling and minimizing the harmful consequences associated with breast cancer screening.

Mammographic breast density, body mass index and risk of breast cancer in Korean women aged 75 years and older

Mammographic breast density and body mass index (BMI) are strong risk factors of breast cancer, but few studies have investigated these factors in older women. Our study assessed the association between breast density, BMI and the breast cancer risk among women aged ≥75 years. We included women who underwent breast cancer screening between 2009 and 2014 and were followed up until 2020. Breast density was measured using Breast Imaging Reporting and Data System. BMI was classified into three groups: <23, 23 to <25 and ≥25. Cox proportional hazards models were used to estimate the association of breast density and BMI with breast cancer risk. In 483 564 women, 1885 developed breast cancer. The 5-year incidence increased with an increase in breast density and BMI. Increase in breast density was associated with an increased breast cancer risk in all BMI categories: among women with BMI <23, those with heterogeneous/extreme density had a 2.98-fold (95% CI: 2.23-3.80) increased risk of breast cancer compared to those with entirely fatty breasts. An increase in BMI was associated with increased breast cancer risk in women with the same breast density in all density categories. When the combined associations of breast density and BMI on the risk of breast cancer were considered, women with a BMI ≥25 and heterogeneous/extreme breast density had a 5.35-fold (95% CI: 4.26-6.72) increased risk of breast cancer compared to women with a BMI <23 and fatty breasts. Women aged ≥75 years, with dense breasts, regardless of BMI status, might benefit from a tailored screening strategy for early detection of breast cancer.

Dilemmas of nudging in public health: an ethical analysis of a Danish pamphlet

Nudging has been discussed in the context of public health, and ethical issues raised by nudging in public health contexts have been highlighted. In this article, we first identify types of nudging approaches and techniques that have been used in screening programmes, and ethical issues that have been associated with nudging: paternalism, limited autonomy and manipulation. We then identify nudging techniques used in a pamphlet developed for the Danish National Screening Program for Colorectal Cancer. These include framing, default nudge, use of hassle bias, authority nudge and priming. The pamphlet and the very offering of a screening programme can in themselves be considered nudges. Whether nudging strategies are ethically problematic depend on whether they are categorized as educative- or non-educative nudges. Educative nudges seek to affect people's choice making by engaging their reflective capabilities. Non-educative nudges work by circumventing people's reflective capabilities. Information materials are, on the face of it, meant to engage citizens' reflective capacities. Recipients are likely to receive information materials with this expectation, and thus not expect to be affected in other ways. Non-educative nudges may therefore be particularly problematic in the context of information on screening, also as participating in screening does not always benefit the individual.

Informing Women About Overdetection in Breast Cancer Screening: Two-Year Outcomes From a Randomized Trial

BACKGROUND

Supporting well-informed decisions about breast cancer screening requires communicating that inconsequential disease may be detected, leading to overdiagnosis and overtreatment. Having previously shown that telling women about overdetection improved informed choice, we investigated effects on screening knowledge and participation over 2 years.

METHODS

We conducted a community-based, parallel-group, randomized controlled trial in Australia. Participants were women aged 48-50 years, without personal or strong family history of breast cancer, who had not undergone mammography in the past 2 years. We randomly assigned 879 women to receive the intervention decision aid (evidence-based information on overdetection, breast cancer mortality reduction, and false-positives) or control decision aid (identical but without overdetection information). We interviewed 838 women postintervention and recontacted them for follow-up at 6 months and 1 and 2 years. Main outcomes for this report are screening knowledge and participation.

RESULTS

We interviewed 790, 746, and 712 participants at 6 months, 1, and 2 years, respectively. The intervention group demonstrated superior knowledge throughout follow-up. After 2 years, conceptual knowledge was adequate in 123 (34.4%) of 358 women in the intervention group compared with 71 (20.1%) of 354 control participants(odds ratio = 2.04, 95% confidence interval = 1.46 to 2.85). Groups were similar in total screening participation (200 [55.1%] vs 204 [56.0%]; = 0.97, 95% confidence interval = 0.73 to 1.29).

CONCLUSIONS

A brief decision aid produced lasting improvement in women's understanding of potential consequences of screening, including overdetection, without changing participation rates. These findings support the use of decision aids for breast cancer screening.

Mortality risks among blue- and white-collar workers: A time series study among Japanese men aged 25-64 years from 1980 to 2015

OBJECTIVE

We aimed to analyse age-standardised mortality trends in Japan among blue- and white-collar male workers aged 25-64 years, by major causes of mortality from 1980 to 2015.

METHODS

Five-yearly mortality data were extracted from occupation-specific vital statistics maintained by the Japanese Ministry of Health, Labour and Welfare. A time series study was conducted among employed men aged 25-64 years. Age-standardised mortality trends by occupational category were calculated separately for all cancers, ischaemic heart disease, cerebrovascular disease and suicide. Poisson regression analysis was performed to analyse mortality trends by occupational category for each cause.

RESULTS

Mortality rates for all cancers and ischaemic heart disease were higher among white-collar workers than blue-collar workers throughout the 35-year study period. The gap in the mortality rates for all four causes of death among blue- and white-collar workers widened in 2000 after Japan's economic bubble burst in the late 1990s. Simultaneously, suicide mortality rates among white-collar workers increased sharply and have remained higher than among blue-collar workers.

CONCLUSIONS

White-collar male workers in Japan have a higher risk of mortality than male blue-collar workers. However, despite substantial differences, significant progress has been made in recent years in reducing mortality across all occupations in Japan.

Variations in intrinsic breast cancer characteristics in screen-detected breast cancer patients aged between 45 and 69 and above the age of 70

BACKGROUND

Increasing age is a well-recognized risk factor for breast cancer. With an increase in life expectancy of women, more older patients are diagnosed with breast cancer. This study aimed to identify the variations in breast cancer attributes and mortality in different age groups in New Zealand.

METHODS

This was a retrospective study of data from the Auckland Breast Cancer Register between 1 June 2000 and 28 February 2017. Patients who were diagnosed through Breast Screen were included. Group A included those aged between 45 and 69 years. Group B included individuals with an age of 70 years or above.

RESULTS

From June 2000 to February 2017, a total of 6304 new cases of new breast cancer were diagnosed through Auckland Breast Screen, with 5788 patients in group A and 516 patients in group B. Group B was more likely to have the lower grade invasive cancers, with fewer grade 3 cancers. Oestrogen receptor positivity was more pronounced in group B, along with progesterone receptor positivity. Conversely, HER-2 receptor was less likely to be positive in group B. There was a significantly higher breast cancer-related mortality in group B (6.0% versus 2.7%). Mortality related to other causes was also much higher in group B as compared to that in group A (12.8% versus 2.5%).

CONCLUSION

Women aged 70 years or above generally tend to have a more favourable type of breast cancer, with a lower tumour grade, oestrogen and progesterone receptor positivity, and lower rate of HER-2 overexpression.

Heritability of Mammographic Breast Density, Density Change, Microcalcifications, and Masses

Mammographic features influence breast cancer risk and are used in risk prediction models. Understanding how genetics influence mammographic features is important because the mechanisms through which they are associated with breast cancer are not well known. Here, using mammographic screening history and detailed questionnaire data from 56,820 women from the KARMA prospective cohort study, we investigated the association between a genetic predisposition to breast cancer and mammographic features among women with a family history of breast cancer (N = 49,674) and a polygenic risk score (PRS, N = 9,365). The heritability of mammographic features such as dense area (MD), microcalcifications, masses, and density change (MDC, cm²/year) was estimated using 1,940 sister pairs. Heritability was estimated at 58% [95% confidence interval (CI), 48%-67%) for MD, 23% (2%-45%) for microcalcifications, and 13% (1%-25%)] for masses. The estimated heritability for MDC was essentially null (2%; 95% CI, -8% to 12%). The association between a genetic predisposition to breast cancer (using PRS) and MD and microcalcifications was positive, while for masses this was borderline significant. In addition, for MDC, having a family history of breast cancer was associated with slightly greater MD reduction. In summary, we have confirmed previous findings of heritability in MD, and also established heritability of the number of microcalcifications and masses at baseline. Because these features are associated with breast cancer risk and can improve detecting women at short-term risk of breast cancer, further investigation of common loci associated with mammographic features is warranted to better understand the etiology of breast cancer. SIGNIFICANCE: These findings provide novel data on the heritability of microcalcifications, masses, and density change, which are all associated with breast cancer risk and can indicate women at short-term risk.

Breast Cancer Screening Trends among Lower Income Women of New York: A Time-Series Evaluation of a Population-Based Intervention

OBJECTIVE

This study aimed to compare the screening rate trends of mammography among New York State's lower-income women and the higher-income women from 1988 to 2010, and evaluate the potential influence of New York State's Breast Cancer Early Detection Program (introduced in 1994) on the mammography use rates of lower-income women.

MATERIALS AND METHODS

Lower-income women are defined as women aged 40 and over whose household income is lower than 250% of the single member household federal poverty level (FPL) in the year that they participated in the survey. Higher-income women are defined as women aged 40 and over whose income is greater than 250% of the five-person household FPL. Data were obtained from the Behavioral Risk Factor Surveillance System. Interrupted time series analysis was conducted to examine screening rates before and after the launch of the Breast Cancer Early Detection program.

RESULTS

Among the lower-income women, the pre-intervention mammography screening rate significantly increased by an average of 15.21% every two years. However, after implementation of the Breast Cancer Early Detection Program, this rate of increase significantly slowed (slope change=-13.67, p=0.00016). The lower-income women and the higher-income women experienced a similar trend change after the intervention started.

CONCLUSION

This study found limited evidence that the Breast Cancer Early Detection Programme significantly contributed to the state-wide increase in mammography screening rate among lower-income women from 1988 to 2010. Future studies should examine the influence of structural and individual barriers inhibiting uptake of mammography screening among lower-income women.

Breast cancer overdiagnosis in stop-screen trials: More uncertainty than previously reported

OBJECTIVE

According to the Independent UK Panel on Breast Cancer Screening, the most reliable estimates of overdiagnosis for breast cancer screening come from stop-screen trials Canada 1, Canada 2, and Malmo. The screen-interval overdiagnosis fraction is the fraction of cancers in a screening program that are overdiagnosed. We used the cumulative incidence method to estimate screen-interval overdiagnosis fraction. Our goal was to derive confidence intervals for estimated screen-interval overdiagnosis fraction and adjust for refusers in these trials.

METHODS

We first show that the UK Panel's use of a 95% binomial confidence interval for estimated screen-interval overdiagnosis fraction was incorrect. We then derive a correct 95% binomial-Poisson confidence interval. We also use the method of latent-class instrumental variables to adjust for refusers.

RESULTS

For the Canada 1 trial, the estimated screen-interval overdiagnosis fraction was 0.23 with a 95% binomial confidence interval of (0.18, 0.27) and a 95% binomial-Poisson confidence interval of (0.04, 0.41). For the Canada 2 trial, the estimated screen-interval overdiagnosis fraction was 0.16 with a 95% binomial confidence interval of (0.12, 0.19) and a 95% binomial-Poisson confidence interval of (-0.01, 0.32). For the Malmo trial, the estimated screen-interval overdiagnosis fraction was 0.19 with a 95% binomial confidence interval of (0.15, 0.22). Adjusting for refusers, the estimated screen-interval overdiagnosis fraction was 0.26 with a 95% binomial-Poisson confidence interval of (0.03, 0.50).

CONCLUSION

The correct 95% binomial-Poisson confidence interval s for the estimated screen-interval overdiagnosis fraction based on the Canada 1, Canada 2, and Malmo stop-screen trials are much wider than the previously reported incorrect 95% binomial confidence intervals. The 95% binomial-Poisson confidence intervals widen as follow-up time increases, an unappreciated downside of longer follow-up in stop-screen trials.

Patterns of gynaecological check-up and their association with body mass index within the CONSTANCES cohort

OBJECTIVES

To investigate the relationship between patterns of gynaecological check-up and body mass index while accounting for various determinants of health care use.

METHODS

Sequence analysis and clustering were used to highlight patterns of gynaecological check-up, which included the regularity of breast and cervical cancer screening and visits to the gynaecologist over four years, among 6182 women aged 54-65 included in the CONSTANCES cohort between 2013 and 2015 in France. Multinomial logistic regressions were used to study the association between these patterns and women's body mass index.

RESULTS

We identified four patterns of gynaecological check-up, from (A) no or inappropriate check-up (20%) to (D) almost one visit to the gynaecologist every year, overscreening for cervical cancer and frequent use of opportunistic breast cancer screening (12%). From patterns A to D, the proportion of obese women decreased and that of women with normal body mass index increased. Obese and overweight women underwent more breast than cervical cancer screening and were less often overscreened than normal weight women. These differences were only partly explained by the lower socioeconomic situation of overweight and obese women. Beyond the financial barrier, the screening modality and the type of exam may play a role. Among women who were screened for cervical cancer, obese and overweight women were less often screened by a gynaecologist.

CONCLUSION

Further efforts should be made to enhance the take-up of screening among obese women who are deterred by the healthcare system.

An exploration for quantification of overdiagnosis and its effect for breast cancer screening

Objective

To redefine overdiagnosis and reestimate the proportion of overdiagnosis of breast cancer caused by screening based on the Surveillance, Epidemiology, and End Results (SEER, 1973−2015) Program data.

Methods

The breast cancer diagnosed before 1977 was defined as the no-screening cohort since America had initiated breast cancer screening from 1977. The breast cancer diagnosed in 1999 was defined as the screening cohort due to no increases in both the proportion of early-stage breast cancer until 1999 and the overall survival of early-stage breast cancer diagnosed over the three years since 1999. The magnitude of overdiagnosis was calculated as the difference in the proportions of early-stage breast cancer patients with long-time (15-year) survival to all breast cancer patients between two cohorts.

Results

Over 23 years before and after widespread screening in America, the proportion of early-stage breast cancer patients increased from 52.1% (16,891/32,443) to 72.7% (16,021/22,025) (P<0.001). The 15-year survival rate of early-stage breast cancer patients increased from 51.1% to 61.5% (P<0.001), while the proportions of early-stage breast cancer patients with long-time survival to all breast cancer patients increased from 26.6% (52.1%×51.1%) to 44.7% (72.7%×61.5%). Assuming no improvements in cancer screening technology and treatment technology, 18.1% (44.7%−26.6%) of breast cancer patients were overdiagnosed associated with screening. The age-specific overdiagnosis rates were 18.9%, 24.7%, 24.5%, 20.5%, and 8.3% for breast cancer patients aged 40−49, 50−59, 60−69, 70−74, and ≥75 years old, respectively.

Conclusions

Overdiagnosis caused by mammographic screening is probably overestimated in current screening practices. Further trials with more sophisticated designs and analyses are needed to validate our findings in the future.

Can mammogram readers swiftly and effectively learn to interpret first post-contrast acquisition subtracted (FAST) MRI, a type of abbreviated breast MRI?: a single centre data-interpretation study

OBJECTIVES

To assess whether NHS breast screening programme (NHSBSP) mammogram readers could effectively interpret first post-contrast acquisition subtracted (FAST) MRI, for intended use in screening for breast cancer.

METHODS

Eight NHSBSP mammogram readers from a single centre (four who also read breast MRI (Group 1) and four who do not (Group 2)) were given structured FAST MRI reader training (median 4 h: 32 min). They then prospectively interpreted 125 FAST MRIs (250 breasts: 194 normal and 56 cancer) comprising a consecutive series of screening MRIs enriched with additional cancer cases from 2015, providing 2000 interpretations. Readers were blinded to other readers' opinions and to clinical information. Categorisation followed the NHSBSP MRI reporting categorisation, with categories 4 and 5 considered indicative of cancer. Diagnostic accuracy (reference standard: histology or 2 years' follow-up) and agreement between readers were determined.

RESULTS

The accuracy achieved by Group 2 (847/1000 (85%; 95% confidence interval (CI) 82-87%)) was 5% less than that of Group 1 (898/1000 (90%; 95% CI 88-92)). Good inter-reader agreement was seen between both Group 1 readers (κ = 0.66; 95% CI 0.61-0.71) and Group 2 readers (κ = 0.63; 95% CI 0.58-0.68). The median time taken to interpret each FAST MRI was Group 1: 34 s (range 3-351) and Group 2: 77 s (range 11-321).

CONCLUSION

Brief structured training enabled multiprofessional mammogram readers to achieve similar accuracy at FAST MRI interpretation to consultant radiologists experienced at breast MRI interpretation.

ADVANCES IN KNOWLEDGE

FAST MRI could be feasible from a training-the-workforce perspective for screening within NHSBSP.

Double Discourse: Qualitative Perspectives on Breast Screening Participation among Obese Women and Their Health Care Providers

Obesity in Australia is rising rapidly, and is a major public health concern. Obesity increases the risk of breast cancer and worsens associated outcomes, yet breast screening participation rates in Australia are suboptimal and can be lower in higher risk, obese women. This study qualitatively explored barriers to breast screening participation in obese women in Australia. In-depth interviews (n = 29), were conducted with obese women (body mass index ≥ 30) and key health providers. A disconnect between providers’ and women’s perceptions was found. For women, low knowledge around a heightened need to screen existed, they also reported limited desire to prioritize personal health needs, reluctance to screen due to poor body image and prior negative mammographic experiences due to issues with weight. Providers perceived few issues in screening obese women beyond equipment limitations, and health and safety issues. Overall, weight was a taboo topic among our interviewees, indicating that a lack of discourse around this issue may be putting obese women at increased risk of breast cancer morbidity and mortality. Consideration of breast screening policy in obese women is warranted. Targeted health promotion on increased breast cancer risk in obese women is required as is a need to address body image issues and encourage screening participation.

Use of Mastectomy for Overdiagnosed Breast Cancer in the United States: Analysis of the SEER 9 Cancer Registries

Aim

We investigated use of mastectomy as treatment for early breast cancer in the US and applied the resulting information to estimate the minimum and maximum rates at which mastectomy could plausibly be undergone by patients with overdiagnosed breast cancer. Little is currently known about overtreatments undergone by overdiagnosed patients.

Methods

In the US, screening is often recommended at ages ≥40. The study population was women age ≥40 diagnosed with breast cancer in the US SEER 9 cancer registries during 2013 (n=26,017). We evaluated first-course surgical treatments and their associations with case characteristics. Additionally, a model was developed to estimate probability of mastectomy conditional on observed case characteristics. The model was then applied to evaluate possible rates of mastectomy in overdiagnosed patients. To obtain minimum and maximum plausible rates of this overtreatment, we respectively assumed the cases that were least and most likely to be treated by mastectomy had been overdiagnosed.

Results

Of women diagnosed with breast cancer at age ≥40 in 2013, 33.8% received mastectomy. Mastectomy was common for most investigated breast cancer types, including for the early breast cancers among which overdiagnosis is thought to be most widespread: mastectomy was undergone in 26.4% of in situ and 28.0% of AJCC stage-I cases. These rates are substantively higher than in many European nations. The probability-based model indicated that between >0% and <18% of the study population could plausibly have undergone mastectomy for overdiagnosed cancer. This range reduced depending on the overdiagnosis rate, shrinking to >0% and <7% if 10% of breast cancers were overdiagnosed and >3% and <15% if 30% were overdiagnosed.

Conclusions

Screening-associated overtreatment by mastectomy is considerably less common than overdiagnosis itself but should not be assumed to be negligible. Screening can prompt or prevent mastectomy, and the balance of this harm-benefit tradeoff is currently unclear.

Mortality of women with ductal carcinoma in situ of the breast: a population-based study from the Girona province, Spain (1994-2013)

PURPOSE

We aim to comprehensively describe the incidence and mortality trends of ductal carcinoma in situ (DCIS) in the Girona province, Spain (1994-2013) and to estimate the all-cause mortality excess risk of diagnosed women.

METHODS

Age-standardized rates of DCIS were estimated between 1994 and 2013. Standard mortality ratios (SMR) and absolute excess mortality were calculated overall and by tumor and patient characteristics. A sensitivity analysis was conducted excluding cases with a subsequent invasive breast cancer (sIBC).

RESULTS

Of the 641 women included, 56 died (follow-up time: 8.4 person-years). Between 1994 and 2013, a significant increase in incidence and decrease in mortality was identified among women aged between 50 and 69 years old. Neoplasms and circulatory system disease were the most common causes of death. No excess risk of death was found overall, except for women aged < 50 years (SMR = 3.44, 95% CI 1.85; 6.40) and those with a sIBC (SMR = 2.51, 95% CI 1.26; 5.02), risk that lessened when cases with sIBC were excluded. Patients with sIBC also showed an excess risk (SMR = 2.29, 95% CI 1.03; 5.10).

CONCLUSIONS

Among women aged 50-69 years old, incidence of DCIS has significantly increased yet mortality has decreased. Overall, the all-cause mortality risk of women diagnosed with DCIS remains similar to that of the general population except for women diagnosed before age 50 and those with sIBC, who showed a significant increased risk. Differential management of these patients should be considered.

Nudging in screening: Literature review and ethical guidance

OBJECTIVES

Nudging is the purposeful alteration of choices presented to people that aims to make them choose in predicted ways. While nudging has been used to assure high uptake and good outcome of screening programs, it has been criticized for being paternalistic, undermining free choice, and shared decision making. Accordingly, the objective of this study is to explore a) nudging strategies identified in screening, b) arguments for and against nudging; and on basis of this, to c) suggest a tentative conclusion on how to handle nudging in screening.

METHODS

Literature searches in Ovid MEDLINE and PsycINFO for combinations of screening and nudging. Screening based on content analysis of titles, abstracts, and articles.

RESULTS

239 references were identified and 109 were included. Several forms of nudging were identified: framed information, default bias, or authority bias. Uptake and public health outcome were the most important goals. Arguments for nudging were bounded rationality, unavoidability, and beneficence, while lack of transparency, crowding out of intrinsic values, and paternalism were arguments against it. The analysis indicates that nudging can be acceptable for screenings with (high quality) evidence for high benefit-harm ratio (beneficence), where nudging does not infringe other ethical principles, such as justice and non-maleficence. In particular, nudging should not only focus on attendance rates, but also on making people "better choosers."

PRACTICE IMPLICATIONS

Four specific recommendations follow from the review and the analysis: 1) Nudging should be addressed in an explicit and transparent manner. 2) The means of nudging have to be in proportion to the benefit-harm ratio. 3) Disagreement on the evidence for either benefits or harms warrants special care. 4) Assessing and assuring the intended outcome of nudging appears to be crucial, as it can be context dependent.

Occupational inequalities in female cancer incidence in Japan: Hospital-based matched case-control study with occupational class

BACKGROUND

Socioeconomic inequalities in female cancer incidence have previously been undocumented in Japan.

METHODS

Using a nationwide inpatient dataset (1984-2016) in Japan, we identified 143,806 female cancer cases and 703,157 controls matched for sex, age, admission date, and admitting hospital, and performed a hospital-based matched case-control study. Based on standardized national classification, we categorized patients' socioeconomic status (SES) by occupational class (blue-collar, service, professional, manager), cross-classified by industry sector (blue-collar, service, white-collar). Using blue-collar workers in blue-collar industries as the reference group, we estimated the odds ratio (OR) for each cancer incidence using conditional logistic regression with multiple imputation, adjusted for major modifiable risk factors (smoking, alcohol consumption).

RESULTS

We identified lower risks among higher-SES women for common and overall cancers: e.g., ORs for managers in blue-collar industries were 0.67 (95% confidence interval [CI], 0.46-0.98) for stomach cancer and 0.40 (95% CI, 0.19-0.86) for lung cancer. Higher risks with higher SES were evident for breast cancer: the OR for professionals in service industries was 1.60 (95% CI, 1.29-1.98). With some cancers, homemakers showed a similar trend to subjects with higher SES; however, the magnitude of the OR was weaker than those with higher SES.

CONCLUSIONS

Even after controlling for major modifiable risk factors, socioeconomic inequalities were evident for female cancer incidence in Japan.

A systematic review of barriers and enablers to South Asian women's attendance for asymptomatic screening of breast and cervical cancers in emigrant countries

OBJECTIVES

The aim of this review was to identify the cultural, social, structural and behavioural factors that influence asymptomatic breast and cervical cancer screening attendance in South Asian populations, in order to improve uptake and propose priorities for further research.

DESIGN

A systematic review of the literature for inductive, comparative, prospective and intervention studies. We searched the following databases: MEDLINE/In-Process, Web of Science, EMBASE, SCOPUS, CENTRAL, CDSR, CINAHL, PsycINFO and PsycARTICLES from database inception to 23 January 2018. The review included studies on the cultural, social, structural and behavioural factors that influence asymptomatic breast and cervical cancer screening attendance and cervical smear testing (Papanicolaou test) in South Asian populations and those published in the English language. The framework analysis method was used and themes were drawn out following the thematic analysis method.

SETTINGS

Asymptomatic breast or cervical screening.

PARTICIPANTS

South Asian women, including Bangladeshi, Indian, Pakistani, Sri Lankan, Bhutanese, Maldivian and Nepali populations.

RESULTS

51 included studies were published between 1991 and 2018. Sample sizes ranged from 25 to 38 733 and participants had a mean age of 18 to 83 years. Our review showed that South Asian women generally had lower screening rates than host country women. South Asian women had poorer knowledge of cancer and cancer prevention and experienced more barriers to screening. Cultural practices and assumptions influenced understandings of cancer and prevention, emphasising the importance of host country cultures and healthcare systems.

CONCLUSIONS

High-quality research on screening attendance is required using prospective designs, where objectively validated attendance is predicted from cultural understandings, beliefs, norms and practices, thus informing policy on targeting relevant public health messages to the South Asian communities about screening for cancer.

PROSPERO REGISTRATION NUMBER

CSD 42015025284.

How information about overdetection changes breast cancer screening decisions: a mediation analysis within a randomised controlled trial

OBJECTIVES

In a randomised controlled trial, we found that informing women about overdetection changed their breast screening decisions. We now present a mediation analysis exploring the psychological pathways through which study participants who received the intervention processed information about overdetection and how this influenced their decision-making. We examined a series of potential mediators in the causal chain between exposure to overdetection information and women's subsequently reported breast screening intentions.

DESIGN

Serial multiple mediation analysis within a randomised controlled trial.

SETTING

New South Wales, Australia.

PARTICIPANTS

811 women aged 48-50 years with no personal history of breast cancer.

INTERVENTIONS

Two versions of a decision aid giving women information about breast cancer deaths averted and false positives from mammography screening, either with (intervention) or without (control) information on overdetection.

MAIN OUTCOME

Intentions to undergo breast cancer screening in the next 2-3 years.

MEDIATORS

Knowledge about overdetection, worry about breast cancer, attitudes towards breast screening and anticipated regret.

RESULTS

The effect of information about overdetection on women's breast screening intentions was mediated through multiple cognitive and affective processes. In particular, the information led to substantial improvements in women's understanding of overdetection, and it influenced-both directly and indirectly via its effect on knowledge-their attitudes towards having screening. Mediation analysis showed that the mechanisms involving knowledge and attitudes were particularly important in determining women's intentions about screening participation.

CONCLUSIONS

Even in this emotive context, new information influenced women's decision-making by changing their understanding of possible consequences of screening and their attitudes towards undergoing it. These findings emphasise the need to provide good-quality information on screening outcomes and to communicate this information effectively, so that women can make well-informed decisions.

TRIAL REGISTRATION NUMBER

This study was prospectively registered with the Australian New Zealand Clinical Trials Registry (ACTRN12613001035718) on 17 September 2013.

Impact of extending screening mammography to older women: Information to support informed choices

From 2013 through 2017, the Australian national breast cancer screening programme is gradually inviting women aged 70-74 years to attend screening, following a policy decision to extend invitations to older women. We estimate the benefits and harms of the new package of biennial screening from age 50-74 compared with the previous programme of screening from age 50-69. Using a Markov model, we applied estimates of the relative risk reduction for breast cancer mortality and the risk of overdiagnosis from the Independent UK Panel on Breast Cancer Screening review to Australian breast cancer incidence and mortality data. We estimated screening specific outcomes (recalls for further imaging, biopsies, false positives, and interval cancer rates) from data published by BreastScreen Australia. When compared with stopping at age 69, screening 1,000 women to age 74 is likely to avert one more breast cancer death, with an additional 78 women receiving a false positive result and another 28 women diagnosed with breast cancer, of whom eight will be overdiagnosed and overtreated. The extra 5 years of screening results in approximately 7 more overdiagnosed cancers to avert one more breast cancer death. Thus extending screening mammography in Australia to older women results in a less favourable harm to benefit ratio than stopping at age 69. Supporting informed decision making for this age group should be a public health priority.