Adjusting the frequency of mammography screening on the basis of genetic risk: Attitudes among women in the UK

Abstract

Purpose

To explore public attitudes towards modifying frequency of mammography screening based on genetic risk.

Methods

Home-based interviews were carried out with a population-based sample of 942 women aged 18–74 years in the UK. Demographic characteristics and perceived breast cancer (BC) risk were examined as predictors of support for risk-stratified BC screening and of the acceptability of raised or lowered screening frequency based on genetic risk, using multivariate logistic regression.

Results

Over two-thirds of respondents (65.8%) supported the idea of varying screening frequency on the basis of genetic risk. The majority (85.4%) were willing to have more frequent breast screening if they were found to be at higher risk, but fewer (58.8%) were willing to have less frequent screening if at lower risk (t (956) = 15.6, p < 0.001). Ethnic minority status was associated with less acceptability of more frequent screening (OR = 0.40, 95% CI = 0.21–0.74), but there were no other significant demographic correlates. Higher perceived risk of BC was associated with greater acceptability of more frequent screening (OR = 1.71, 95%CI = 1.27–2.30).

Conclusion

Women were positive about adjusting the frequency of mammography screening in line with personal genetic risk, but it will be important to develop effective communication materials to minimise resistance to reducing screening frequency for those at lower genetic risk.

Introduction

Breast cancer screening by mammography has been identified as reducing deaths from breast cancer; nonetheless, false positives, overdiagnosis and overtreatment have all been identified as potential harms [1], [2]. Routine screening is usually recommended for women above age 50 [http://www.cancerscreening.nhs.uk/; http://www.who.int/cancer/detection/variouscancer/en/; http://www.cdc.gov/cancer/dcpc/prevention/screening.htm]; although women with a strong family history of breast cancer may be offered screening from an earlier age [3] http://www.cancerscreening.nhs.uk/; http://www.cdc.gov/cancer/dcpc/prevention/screening.htm). However, approximately 20% of all breast cancers occur in women younger than age 50 [4]; with a substantial proportion in women without a family history. These cancers tend to be aggressive with a poorer prognosis [5], [6], and therefore early identification, irrespective of known family history, might be beneficial.

Given the number of genetic markers for breast cancer risk that have been identified [7], [8], [9], incorporating genetic risk assessment into current mammography screening has been proposed as one way to maximise benefits and minimise harms [10]. Modifying screening eligibility and frequency to account for genetic risk could make it possible to ‘tailor’ screening and risk management efforts to those at the highest risk, for example by shortening screening intervals, or by offering screening using alternative modalities such as Magnetic Resonance Imaging (MRI) and ultrasound. At the same time, it would minimise exposure to potential harms of screening for those at the lowest risk; for example by starting screening later or by making a recommendation against routine mammography screening in this group. Risk-stratified mammography screening based on genetic risk could therefore be superior to current age-stratified approaches [11], [12].

However, implementation of genomic risk-stratified breast screening would require the support of the wider public. The public is generally very enthusiastic about screening [13], [14]. Women perceive high benefits of mammography screening [15], [16]; reflected in the high attendance rates (around 70%) across countries [17], [18], [19]; although lower socioeconomic status (SES) and ethnic minority status have both been associated with lower participation rates [20], [21], [22]. Perceived risk of breast cancer has been cited as encouraging some individuals to be screened, while deterring others [16], [23], [24]; so predicting the impact of giving genetic risk information on screening uptake is difficult. There has also been attention to public perceptions of a ‘right to be screened’, which may militate against the acceptability of reducing breast screening frequency for those at the lowest risk.

Few studies to date have investigated public attitudes to ‘personalised’ cancer screening, despite calls for empirical research on the topic [10], [25]. One qualitative study in the Netherlands found that women were supportive of both increases and reductions in breast screening frequency, although there was an important proviso that any woman who was worried about breast cancer despite having low genetic risk, should still be able to access screening [26]. A small qualitative study in the UK found enthusiasm for risk-stratified ovarian cancer screening based on genetic risk [27], but these findings cannot be assumed to generalise to an existing and very popular mammography breast screening programme; especially given evidence from two studies that show that information on overdiagnosis is not a deterrent for mammography screening for most women [14], [28].

Given that research is under way to test the feasibility of ‘personalising’ mammography screening based on individual risk factors, including genetic risk [29], the primary aim of this study was to investigate public attitudes towards amending the frequency of breast cancer screening based on genetic risk in the current UK National Health Service Breast Cancer Screening Programme. Data were from a large, population-based study, making it possible to identify demographic and personal predictors of support for raising or lowering frequency of cancer screening based on genetic risk.