Introduction: Black men are twice as likely to be diagnosed with prostate cancer than White men. Raised prostate-specific antigen (PSA) levels can indicate an increased risk of prostate cancer, however it is not known whether PSA levels differ for men of different ethnic groups. Methods: PubMed and Embase were searched to identify studies that reported levels of PSA for men of at least two ethnic groups without a prostate cancer diagnosis or symptoms suggestive of prostate cancer. An adaptation of the Newcastle-Ottawa scale was used to assess risk of bias and study quality. Findings were stratified into the following broad ethnic groups: White, Black, Asian, Hispanic, and Other. Data were analysed in a narrative synthesis due to the heterogeneity of reported PSA measures and methods in the included studies. Results: A total of 654 197 males from 13 studies were included. By ethnicity, this included 536 201 White (82%), 38 287 Black (6%), 38 232 Asian (6%), 18 029 Pacific Island (3%), 13 614 Maori (2%), 8 885 Hispanic (1%), and 949 Other (<1%) men aged ≥40 years old. Black men had higher PSA levels than White men, and Hispanic men had similar levels to White men and lower levels than Black men. Conclusions: Black men without prostate cancer have higher PSA levels than White or Hispanic men, which reflects the higher rates of prostate cancer diagnosis in Black men. Despite that, the diagnostic accuracy of PSA for prostate cancer for men of different ethnic groups is unknown, and current guidance for PSA test interpretation does not account for ethnicity. Future research needs to determine whether Black men are diagnosed with similar rates of clinically significant prostate cancer to White men, or whether raised PSA levels are contributing to overdiagnosis of prostate cancer in Black men.

Background: Black men have higher prostate-specific antigen (PSA) levels and higher prostate cancer incidence and mortality than White men, while Asian men tend to have lower prostate cancer incidence and mortality than White men. Much of the evidence comes from the USA, and information from UK populations is limited. Methods: This retrospective cohort study used data on patients registered at general practices in England contributing to the Clinical Practice Research Datalink (CPRD) Aurum dataset. Those eligible were men aged 40 and over with a record of ethnicity and a PSA test result recorded between 2010 and 2017 with no prior cancer diagnosis. The aim was to assess the incidence of prostate cancer following a raised PSA test result in men from different ethnic groups. Additionally, incidence of advanced prostate cancer was investigated. Cancer incidence was estimated from multi-level logistic regression models adjusting for potential confounding factors. Results: 730,515 men with a PSA test were included (88.9% White). Black men and men with mixed ethnicity had higher PSA values, particularly for those aged above 60 years. In the year following a raised PSA result (using age-specific thresholds), Black men had the highest prostate cancer incidence at 24.7% (95% CI 23.3%, 26.2%); Asian men had the lowest at 13.4% (12.2%, 14.7%); incidence for White men was 19.8% (19.4%, 20.2%). The peak incidence of prostate cancer for all groups was in men aged 70–79. Incidence of prostate cancer diagnosed at an advanced stage was similar between Black and White men. Conclusions: More prostate cancer was diagnosed in Black men with a raised PSA result, but rates of advanced prostate cancer were not higher in this group. In this large primary care-based cohort, the incidence of prostate cancer in men with elevated PSA levels increases with increasing age, even when using age-adjusted thresholds, with Black men significantly more likely to be diagnosed compared to White or Asian men. The incidence of advanced stage prostate cancer at diagnosis was similar for Black and White men with a raised PSA result, but lower for Asian men.

Background: In primary care, health professionals use blood tests to investigate nonspecific presentations to inform referral decisions. Reference ranges for the commonly used blood tests in western countries were developed in predominately White populations, and so may perform differently when applied to non-White populations. Knowledge of ethnic variation in blood test results in healthy/general populations could help address ethnic inequalities in cancer referral for diagnosis and outcomes. Objective: This systematic review explored evidence of ethnic differences in the distribution of selected blood test results among healthy/general populations to inform future research aimed at addressing inequalities in cancer diagnosis. Methods: We searched PubMed and EMBASE to identify studies reporting measures of haemoglobin, MCV, calcium, albumin, platelet count, and CRP in nondiseased adults from at least 2 different ethnic groups. Two reviewers independently screened studies, completed data extraction and quality assessment using an adapted Newcastle-Ottawa scale. Participants were stratified into White, Black, Asian, Mixed, and Other groups. Data were synthesised narratively and meta-analyses were conducted where possible. Results: A total of 47 papers were included. Black men and women have lower average values of haemoglobin, MCV, and albumin, and higher average values of CRP relative to their White counterparts. Additionally, Black men have lower average haemoglobin than Asian men, whereas Asian women have lower average CRP values when compared with White women. Conclusions: There is evidence of ethnic differences in average values of haemoglobin, MCV, CRP, and albumin in healthy/general populations. Further research is needed to explore the reasons for these differences. Systematic review registration: CRD42021274580

Background: CA-125 testing is a recommended first line investigation for women presenting with possible symptoms of ovarian cancer in English primary care, to help determine whether further investigation for ovarian cancer is needed. It is currently not known how well the CA-125 test performs in ovarian cancer detection for patients from different ethnic groups. Methods: A retrospective cohort study utilising English primary care data linked to the national cancer registry was undertaken. Women aged ≥ 40 years with a CA-125 test between 2010 and 2017 were included. Logistic regression predicted one-year ovarian cancer incidence by ethnicity, adjusting for age, deprivation status, and comorbidity score. The estimated incidence of ovarian cancer by CA-125 level was modelled for each ethnic group using restricted cubic splines. Results: The diagnostic performance of CA-125 differed for women from different ethnicities. In an unadjusted analysis, predicted CA-125 levels for Asian and Black women were higher than White women at corresponding probabilities of ovarian cancer. The higher PPVs for White women compared to Asian or Black women were eliminated by inclusion of covariates. Conclusion: The introduction of ethnicity-specific thresholds may increase the specificity and PPVs of CA-125 in ovarian cancer detection at the expense of sensitivity, particularly for Asian and Black women. As such, we cannot recommend the use of ethnicity-specific thresholds for CA-125.

Background: Haemoglobin, mean corpuscular volume (MCV), and rates of iron-deficiency anaemia (IDA) are used in primary care to investigate possible cancer symptoms, especially for gastrointestinal cancers. Underlying ethnic differences in typical test results could lead to inequalities in the diagnosis of cancer in primary care. Aim: To investigate the distribution of low haemoglobin, low MCV, and IDA, and the rate of cancer diagnosis in patients with abnormal results, by ethnic group. Design and setting: A retrospective cohort study using routine data collected in primary care in England was undertaken. Included patients had blood tests between 2010 and 2017, and were aged ≥40 years with no prior cancer diagnosis. Method: Multilevel logistic regression was used to investigate the relationship between blood test results and cancer risk for patients in different ethnic groups. Results: Low haemoglobin, low MCV, and IDA were effective in identifying patients with increased cancer risk, particularly for gastrointestinal cancers. MCV was found to be a stronger cancer indicator for White patients (diagnostic odds ratio [OR] 3.84; 95% confidence interval [CI] = 3.72 to 3.96) than for Asian (OR 1.86; 95% CI = 1.64 to 2.10) or Black patients (OR 1.75; 95% CI = 1.54 to 1.99). Conclusion: There are some small differences in cancer risk for patients with abnormal test results, when considering patient ethnic group, especially for MCV. This is likely to be a consequence of the underlying difference in typical MCV values for patients from different ethnic groups. Further investigation is required to understand the aetiology of these differences in order to disentangle any effects on outcomes for patients with cancer.

Background: UK Asian and Black patients experience longer cancer diagnostic intervals — the period between initial symptomatic presentation in primary care and cancer diagnosis. Aim: To determine whether the differences in diagnostic intervals are because of prolonged primary care, referral, or secondary care interval. Design and setting: A cohort study was undertaken of 70 971 patients with seven cancers (breast, lung, prostate, colorectal, oesophagogastric, myeloma, ovarian) diagnosed after symptom presentation in English primary care. Method: Data on symptom presentation and diagnosis were extracted from cancer registry-linked primary care and secondary care data. Primary interval was defined as the period between first primary care presentation and secondary care referral, referral interval as the period between referral and first secondary care appointment, and secondary care interval as the period between the first secondary care appointment and diagnosis. Accelerated failure time models were used to investigate ethnic differences across all four intervals. Results: Across all sites, the median diagnostic interval was 46 days, ranging from 13 days for breast cancer to 116 days for lung cancer. It was 14% longer for Black patients (adjusted time ratio [ATR] 1.14, 95% confidence interval [CI] = 1.05 to 1.25) and 13% longer for Asian patients (ATR 1.13, 95% CI = 1.03 to 1.23) compared with White patients. Site-specific analyses showed that, for myeloma, lung, prostate, and colorectal cancer, the secondary care interval was longer in Asian and Black patients, who also had a longer primary care interval in breast and colorectal cancer. There was little evidence of ethnic differences in referral interval. Conclusion: This study found evidence of ethnic differences in diagnostic intervals, with prolonged secondary care intervals for four common cancers and prolonged primary care intervals for two. Although these differences are relatively modest, they are unjustified and may indicate shortcomings in healthcare delivery that disproportionately affect ethnic minorities.