Background
Ethnic minorities in multi-ethnic societies such as the UK and USA have poorer outcomes for some cancer types when compared with the majority [
1‐
4]. Evidence from the USA (where historical data on ethnicity exists) shows that non-Hispanic Black Americans have the highest mortality for nearly all major cancer types compared to other ethnic groups [
5]. In the UK, despite major limitations to data on ethnicity, a recent report shows that Asian-Pakistani, Black African and Caribbean people have a higher proportion of advanced-stage lung cancer compared to their British White counterparts, with the black groups also having higher proportions of advanced-stage female breast and colorectal cancers [
6]. Advanced-stage at diagnosis is strongly associated with lower cancer survival and is thought to contribute significantly to the UK’s poorer cancer outcomes relative to other developed countries [
7,
8]. Efforts to improve cancer outcomes in the UK are largely geared towards promoting early diagnosis of cancer; minimising ethnic inequalities is considered a key aspect to this [
9].
However, the causes of ethnic inequalities in cancer diagnosis are complex and not fully understood [
1]. Evidence shows that when compared to the majority, ethnic minorities have poorer awareness of symptoms and are less likely to accept screening. Additionally, once symptoms have occurred, a systematic review showed that these minority groups are more likely to delay primary care consultation and may experience unduly prolonged diagnostic interval in female breast, oesophageal, lung and colorectal cancers [
10]. We have also shown in a vignette-based study that Black men were less willing to accept prostate-specific antigen (PSA) testing and digital rectal examination (DRE) when presented with hypothetical scenarios about prostate cancer risks, symptoms, investigations and possible prognoses [
11]. Some of these inequalities may be related to differences across ethnic groups in health literacy, although few UK studies have specifically examined this subject area.
Health literacy refers to a set of cognitive and social skills required to understand, access and use information in ways which promote and maintain good health [
12]. In England, recent data shows that an estimated 43% of adults aged 16–65 years have limited literacy in health [
13]. Indeed, when both literacy and the numeracy components of health materials were combined, around 60% of all English adults were unable to understand oral and written health information received from their doctor or awareness campaign materials [
13]. Limited health literacy has been linked to poorer health status, advanced-stage at diagnosis, higher mortality rates and decreased involvement in clinical trials [
14‐
16]. In relation to ethnicity, a number of studies, particularly in the UK and the USA have demonstrated that ethnic minority groups are at a higher risk of being below the average health literacy threshold [
13,
17,
18].
However, the extent to which this may contribute to ethnic inequalities in diagnosis and outcomes of symptomatic cancer is uncertain. Given the increasing need for shared decision-making and patient involvement in the diagnostic process, understanding the potential impact of ethnic differences in health literacy is important. The present study aims to critically examine the evidence in this area.
Discussion
Empirical evidence is limited in relation to ethnic inequality in diagnosis and outcomes of symptomatic cancer, particularly in the context of a universal health care system such as the UK’s National Health Service. This systematic review will identify and critically evaluate the evidence regarding the impact of health literacy on primary care consultation, diagnostic intervals and outcomes of symptomatic cancer across ethnic groups. To the best of our knowledge, this is the first review in the UK to examine this subject. The involvement of two independent reviewers in screening, data extraction and quality appraisal will enhance the reliability of the conclusions drawn.
Conversely, the exclusion of studies conducted in South America, Africa, Asia and the Middle East due to the differences in healthcare systems will limit the findings of this review. It may be very difficult and inappropriate to synthesise results of studies conducted in these very different healthcare systems. This review may also be limited by publication bias as studies showing no association between health literacy and cancer diagnostic delays by ethnic groups may fail to be published, potentially leaving us with disproportionately positive studies.
Overall, we anticipate that as well as contributing to knowledge, the findings of this review may help shape future interventions to reduce ethnic inequalities in cancer diagnosis and outcomes.
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