Letter regarding ‘the prevalence and predictors of previous prostate cancer screening among men attending primary healthcare centers in Riyadh, Saudi Arabia’

Letter regarding 'the prevalence and predictors of previous prostate cancer screening among men attending primary healthcare centers in Riyadh, Saudi Arabia'To the Editor We read with great interest the article by Alshahrani et al. [1], which provides a valuable cross-sectional analysis of the prevalence and predictors of prostate cancer screening among men attending primary healthcare centres in Riyadh, Saudi Arabia.Given the low screening rate (1.5%) observed, the study highlights a critical public health issue.However, from urological and epidemiological perspectives, we would like to raise several methodological concerns that warrant further clarification.First, there is a noticeable discrepancy between the survey instrument and the clinical conclusions drawn regarding prostate-specific antigen (PSA) testing.According to the methodology, participants were asked: 'Have you ever undergone prostate cancer screening, using at least digital rectal examination (DRE) method?'However, the abstract and discussion heavily emphasize the need to improve access to PSA testing.In modern urological practice, DRE and PSA are distinct entities.DRE is primarily used for physical evaluation (e.g.benign prostatic hyperplasia, prostatitis) and is no longer recommended as a standalone screening tool for prostate cancer due to its limited sensitivity [2].Consequently, participants reporting a previous DRE may not have undergone actual PSA screening.Conflating DRE with PSA testing limits the applicability of the findings to PSA-based screening policies.Second, true cancer screening is defined as the evaluation of asymptomatic individuals [3,4].The authors did not clarify whether men presenting with lower urinary tract symptoms (LUTS), haematuria or prior prostate pathologies were excluded.If an elderly man underwent a DRE or PSA test as part of a diagnostic workup for symptomatic benign prostatic hyperplasia (BPH), this constitutes diagnostic testing, not prophylactic screening.Failing to differentiate between symptom-driven testing and true screening may have further obscured the actual screening prevalence.Third, the robust association found between 'unemployment' and a nearly fourfold higher odds of screening (AOR: 3.69) requires careful interpretation.Given that 68.9% of the study cohort is aged 50 or older (with 20.5% over 75 years), it is highly likely that a substantial proportion of the 'unemployed' category comprises 'retired' individuals.Without distinguishing between actual unemployment (job-seeking) and retirement, this variable might simply act as a proxy for advanced age and increased health encounters, leading to potential residual confounding despite age adjustment in the model.Finally, from a statistical standpoint, the positive outcome is exceedingly rare (86 events out of 6,177 participants, 1.5%).The multivariable logistic regression model incorporates approximately 11 degrees of freedom (including socio-demographic and behavioural variables).This approaches or violates the traditional '10 events per variable (EPV)' rule of thumb, raising concerns about maximum likelihood estimation bias and model overfitting [5].In scenarios with such rare events, utilizing Firth's penalized logistic regression or exact logistic regression would yield more robust and reliable adjusted odds ratios.We commend Alshahrani et al. for shedding light on men's health behaviours in Saudi Arabia.Addressing these nuances in future studies will undoubtedly strengthen the development of targeted and effective prostate cancer screening strategies in the region.