Integrating anamnestic and lifestyle data with sphingolipid levels for risk-based prostate cancer screening

Background In the era of risk-based prostate cancer (PCa) screening, overcoming the limitations of prostate-specific antigen (PSA) testing and stratifying men by individual risk is crucial. Our study aims to integrate anamnestic and lifestyle data with circulating biomarkers to minimize unnecessary second-level investigations (SLIs) for patients with suspected PCa, while improving the detection of clinically significant PCa (ISUP>1).

We collected plasma samples, recent clinical history, family cancer history, PSA levels, and lifestyle information from 904 men: 421 undergoing PSA testing, 421 with suspected and 62 with confirmed PCa. Univariable logistic regression was applied to identify ananmestic and lifestyle variables mostly associated with PCa. Penalized logistic regression models predictive of PCa or ISUP>1 PCa were built both using the 814 subjects with complete information for such variables, applying a 10-fold cross validation approach, and dividing the dataset into a training (n=445: 132 PCa, 313 non-PCa) and a test (n=369: 147 PCa, 222 non-PCa) set. The concentration of 50 sphingolipids was analysed on the latter set of 369 subjects by mass-spectrometry, and multivariable penalized regression with 10-fold cross-validation was applied to integrate anamnestic, lifestyle, sphingolipid data. ROC-AUCs on the test sets were compared with PSA ROC-AUCs.

Age, cardiovascular disease (CVD), number of medications, and sedentariness were significantly associated with PCa detection and their combination with PSA improved its performance (ROC-AUC from 0.85 to 0.89). In the SLI subgroup (n=437), adding age improved PSA predictive power (ROC-AUC from 0.60 to 0.70), but performance was still poor. Penalized regression with 10-fold cross-validation on the sphingolipid dataset identified hypertension, CVD, PSA, age, and five sphingolipids (HexCer-20, Cer-20, HexCer-24.1, GM3-24.1, DHCer-24) as key variables for accurate PCa classification (average ROC-AUC: 0.92). Cer-20 and CVD were consistently selected by models predicting ISUP>1 PCa. In the SLI subgroup, PSA, age, CVD, SM-16, HexCer-20, HexCer-24.1, DHS1P, and DHCer-24 were selected in all 10 models (average ROC-AUC: 0.83).

Circulating sphingolipids are promising biomarkers that, when combined with PSA, anamnestic, and lifestyle data, may enhance PCa screening precision and reduce the need for invasive, costly examinations. Competing Interest Statement The authors have declared no competing interest. Funding Statement The DP3 study was funded by Compagnia di San Paolo (CP-N; FG); Rete Oncologica del Piemonte e della Valle di Aosta; the National Plan for Complementary Investments to the NRRP, project D34H-Digital Driven Diagnostics, prognostics and therapeutics for sustainable Health care (project code: PNC0000001), Spoke 4 financed by the Italian Ministry of University and Research (MS); Fondazione CRT (CP-N; MM-G; PO; IG; GC). Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The observational clinical protocol called DP3 coordinated by FEET was approved by the Novara ethical committee (AOU Maggiore della Carita') in September 2020 (Prot. N. 968/CE 07/09/2020, integration Prot. N.263/CE, 10/03/2021), in accordance with the Declaration of Helsinki Ethical Principles for Medical Research involving Human Participants. The MH ethical committee (AOU Citta' della Salute e della Scienza) in Turin approved the DP3 study in January 2022 (Prot. N. 521/2021, 10/01/2022). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Footnotes

revised; Table 1 and 3 revised; Figure 1 revised; Figure 2 replaced by revised Figure 3; New Figure 2 added; Figure 3 replaced by revised Figure 4; the text corresponding to revised Figures was revised accordingly in the results section. Data Availability All data produced in the present study are available upon reasonable request to the authors