Association of the serum sialic acid-to-albumin ratio with prostate cancer and bone metastasis: a retrospective cross-sectional study
Yu Ji, Chunhui Guo, Yuxuan Zhao, Li Yi, Renxuan Liu, Laiyuan Qiu, Gangli Gu, Dawei LiBackground
Prostate cancer (PCa) is a growing global health concern, with bone metastasis significantly worsening outcomes. Current diagnostics such as prostate-specific antigen (PSA) lack specificity, therefore, this study aimed to evaluate the clinical utility of the serum sialic acid-to-albumin ratio (SAAR) in assisting the identification of PCa and assessing bone metastasis status.
Materials and Methods
This study retrospectively collected the clinical data form patients diagnosed with PCa and benign prostatic hyperplasia (BPH) at Qilu Hospital of Shandong University from August 2014 to February 2022. SAAR levels were compared between the two groups, and receiver operating characteristic (ROC) curve analysis was performed to assess its discriminative capability. The bone metastasis cohort included 254 patients with PCa whose bone metastasis status was clearly determined, randomly split into training and testing sets. Least absolute shrinkage and selection operator regression (LASSO) was used for variable selection in the training set, followed by multivariable logistic regression to develop a model for assisting in the identification of bone metastasis. Model performance was evaluated using the ROC curve, calibration curve, and decision curve analysis (DCA). To evaluate the incremental value of SAAR, model area under curves (AUCs) were compared using the DeLong test, alongside the calculation of net reclassification improvement (NRI) and integrated discrimination improvement (IDI).
Results
SAAR levels were higher in PCa patients compared to BPH patients, although the ability to differentiate PCa from BPH was limited. Among patients whose bone metastasis status was clearly determined, SAAR levels were significantly higher in those with bone metastasis. Multivariable logistic regression suggested that SAAR may be independently associated with bone metastasis. Further comparisons across multiple models showed that incorporating SAAR into the baseline model of PSA and Gleason score modestly improved discrimination and risk reclassification. The clinical model incorporating SAAR, lactate dehydrogenase (LDH), PSA, and pathological grade demonstrated favorable performance.
Conclusion
SAAR is associated with PCa and the presence of bone metastasis. Its ability to differentiate PCa from BPH is limited, but it may provide adjunctive information for identifying bone metastasis. The proposed model show s acceptable internal performance and requires external validation before clinical use.