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: Thrombocytosis is associated with poor lung cancer prognosis and has recently been identified as having a high positive predictive value in lung cancer detection. Lung cancer has multiple histological and genetic subtypes and it is not known whether platelet levels differ across these subtypes, or whether thrombocytosis is predictive of a particular subtype. Methods: PubMed and Embase were systematically searched for studies that reported pre-treatment platelet count, as either averages or proportion of patients with thrombocytosis, by subtype of lung cancer using a pre-specified search strategy. The Newcastle-Ottowa scale was used to assess study quality and risk of bias. Suitable studies were synthesised in meta-analyses and subgroup analyses examined for differences across subtypes. Results: The prevalence of pre-treatment thrombocytosis across all lung cancer patients was 27% (95% CI: 17% to 37%). By subtype, this was 22% (95% CI: 7% to 41%) for adenocarcinoma, 28% (95% CI: 15% to 43%) for squamous cell carcinoma (SCC), 36% (95% CI: 13% to 62%) for large cell carcinoma (LCC), and 30% (95% CI: 8% to 58%) for small cell lung cancer (SCLC). The pooled mean platelet count for lung cancer patients was 289×10⁹/L (95% CI: 268 to 311). By subtype, this was 282×10⁹/L (95% CI: 259 to 306) for adenocarcinoma, 297×10⁹/L (95% CI: 238 to 356) for SCC, 290×10⁹/L (95% CI: 176 to 404) for LCC, and 293×10⁹/L (95% CI: 244 to 342) for SCLC. There was no difference in thrombocytosis prevalence (P=0.76) or mean platelet count (P=0.96) across the subtypes. Conclusions: These findings suggest thrombocytosis is no more indicative of one lung cancer subtype over another. We therefore conclude a high platelet count is likely to be generic across all lung cancer subtypes.

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: The incidence of early-onset colorectal cancer (EOCRC) is rising rapidly, with diagnoses typically occurring at a more advanced stage than late-onset CRC. In the absence of screening for younger patients, diagnosis relies on symptomatic presentation. The faecal immunochemical test (FIT) is a diagnostic triage tool for patients presenting with clinical features of CRC in primary care, though its performance in individuals under 50 years is not well established. Methods: A cohort of 38,117 symptomatic patients aged 18–49 years in upper South West England underwent FIT in primary care between 01/01/2021 and 10/07/2023. A FIT result of ≥10 µg Hb/g faeces was considered positive. In the same region, 528 EOCRC diagnoses were recorded between 01/01/2021 and 10/10/2024. Results: Of the 528 EOCRC patients, 105 (20%) underwent FIT in the year before diagnosis. The sensitivity of FIT was 92.4% (95% CI 85.5–96.7%), specificity was 88.5% (88.2–88.8%), positive predictive value (PPV) was 2.2% (1.8–2.6%), and negative predictive value was 100% (100–100%). PPVs decreased in younger age groups (18–29, 30–39, 40–49 years). Conclusions: FIT performs excellently for patients aged 40–49; however, it may not be used optimally in patients <40 years. A more targeted strategy is needed to guide investigation in younger patients.