3. Results
3.1. Patient Demographics
A total of 187 male patients were included in the study. All patients underwent evaluation for suspected prostate cancer between October 2023 and March 2025 based on elevated PSA levels (>3 ng/mL) and/or abnormal digital rectal exam (DRE) findings. The median age across the cohort was 64 years (range: 45–79 years). Among these, 53 patients underwent confirmatory prostate biopsies, forming the training cohort for predictive model development, while 134 patients were evaluated using predictive modeling based on EpiSwitch PSE results and clinical parameters.
PSA levels among high likelihood (HLPC) patients (n=88) averaged 9.1 ng/mL (median 8.2 ng/mL, range 4.4–23.6 ng/mL), while low likelihood (LLPC) patients (n=99) showed a mean PSA of 6.1 ng/mL (median 5.3 ng/mL, range 1.3–29.9 ng/mL). There was no meaningful difference in age distribution between HLPC and LLPC groups.
Table 1.
Patient Demographics Baseline demographic and clinical characteristics of the 187 patients included in the retrospective real-world analysis of the EpiSwitch PSE assay. The cohort consisted of 53 biopsy-confirmed patients used for model training and 134 patients without biopsies used for clinical utility testing. All data were collected between 2024 and 2025 from routine urology practice settings.
Table 1.
Patient Demographics Baseline demographic and clinical characteristics of the 187 patients included in the retrospective real-world analysis of the EpiSwitch PSE assay. The cohort consisted of 53 biopsy-confirmed patients used for model training and 134 patients without biopsies used for clinical utility testing. All data were collected between 2024 and 2025 from routine urology practice settings.
| Characteristic |
Value |
| Total Patients |
187 |
| Median Age (years) |
64 |
| Age Range (years) |
45 – 79 |
| PSA Level Range (ng/mL) |
3 – 30 |
| Biopsy Confirmed Patients (Training cohort) |
53 |
| Patients without Biopsies (Testing Cohort) |
134 |
3.2. Clinical Decision Impact
In this study, low-likelihood results from the PSE test played a role in guiding clinical decisions about whether patients should undergo a biopsy. In cases where the PSE result suggested a low probability of PCa, clinicians and patients almost always opted to defer or avoid biopsy. As a result, biopsy data were unavailable for a subset of patients, introducing missing outcomes into the dataset. To address this limitation, cross-validation techniques were employed to predict the testing accuracy of PSE on the missing data using the complete dataset.
Using the EpiSwitch PSE blood test as a triage tool, predictive models indicated that approximately 79.1% of patients could potentially avoid unnecessary prostate biopsies.
Predictive models incorporated EpiSwitch PSE test results alongside relevant clinical parameters. Among these, Model A demonstrated the highest performance, predicting that 79.1% (106 out of 134) of patients could safely avoid unnecessary prostate biopsy based on a negative classification. Model A treated Gleason 3+3 as clinically indolent prostate disease. We also developed Model B that treated 3+3 prostate histology as clinically significant prostate disease. Model B showed that 66.4% (89 out of 134) of patients could avoid biopsy.
These findings consistently highlight the strong potential of the EpiSwitch PSE assay to act as an effective triage tool, substantially reducing the number of invasive diagnostic procedures performed. Internal model validation using 10-fold cross-validation demonstrated stable performance metrics across iterations, underscoring the robustness and clinical applicability of the predictive framework developed in this study.
3.3. Workflow Efficiency and Economic Impact
Operationally, the assay demonstrated a 100% technical success rate, with all 187 samples processed yielding valid results. The average turnaround time (TAT) for PSE testing was 4.4 days, supporting its feasibility for real-world clinical use.
Based on predictive modeling and biopsy outcomes, the PSE assay potentially avoided approximately 97 unnecessary prostate biopsies and 95 MRIs in this cohort of patients who never required a biopsy based on the study protocol. This translates into an estimated cost avoidance of over $230,000, accounting for reduced procedural volume, imaging utilization, and downstream complications such as hospitalizations due to biopsy-related adverse events. The healthcare system could realize an average savings of approximately $1,275 per patient. These data underscore the economic value of incorporating PSE into the prostate cancer diagnostic pathway by improving triage precision, optimizing resource use, and reducing procedural risk.
When extrapolated to the national level, the healthcare economic impact of incorporating PSE into prostate cancer screening workflows could be substantial. An estimated 1 million prostate biopsies are performed annually in the U.S., with as many as 75% deemed potentially unnecessary (11). By more precisely stratifying patients prior to biopsy, PSE has the potential to help avoid up to 593,000 procedures per year, conservatively. At an estimated average cost of $2,500 per biopsy, including procedural, pathology, and complication-related expenses – this represents a potential annual savings of approximately $1.48 billion. When combined with additional cost savings from avoided MRIs and follow-up care, the total economic benefit could approach $2 billion annually. These figures highlight the broader systemic value of deploying blood-based risk stratification tools like PSE in routine prostate cancer diagnostics.
3.4. Feature Importance and Model Interpretation
To better understand the drivers of model predictions, SHAP (SHapley Additive exPlanations) analysis was performed across both predictive models. SHAP values quantify the contribution of each input feature to the final model output, offering transparent insight into how specific clinical and molecular variables influenced individual patient classifications. The initial data split was based on the PSE outcome, and analysis across Models A and B consistently identified the EpiSwitch PSE blood test result as the most influential predictor of biopsy outcome. This highlights that initial guidance via the PSE outcome not only drove the success of the models but also enabled clearer interpretation of other clinical variables, reinforcing the central role of PSE in supporting clinical decision-making.
Figure 1.
SHAP summary plot illustrating feature importance in the predictive model for prostate cancer risk. Each dot represents a single patient, with the position on the x-axis indicating the SHAP value (impact on model output) for that feature. Features are ranked by mean absolute SHAP value, with higher values indicating greater influence on the model’s prediction. Color represents the original value of the feature (purple = low, yellow = high). In this model, the binary EpiSwitch PSE result had the strongest impact on predicted risk when combined with MRI pi_rads with 79.1% of patients would be saved from biopsies.
Figure 1.
SHAP summary plot illustrating feature importance in the predictive model for prostate cancer risk. Each dot represents a single patient, with the position on the x-axis indicating the SHAP value (impact on model output) for that feature. Features are ranked by mean absolute SHAP value, with higher values indicating greater influence on the model’s prediction. Color represents the original value of the feature (purple = low, yellow = high). In this model, the binary EpiSwitch PSE result had the strongest impact on predicted risk when combined with MRI pi_rads with 79.1% of patients would be saved from biopsies.
In parallel, the PI-RADS score from MRI imaging was identified as another major contributing factor, with higher scores favoring a positive biopsy prediction. Other features, such as PSA levels, patient age, and previous 4Kscore® test (OPKO Labs, Elmwood Park, NJ) results, showed secondary but meaningful influence on model behavior. Importantly, in all models, a low-likelihood PSE result heavily shifted predictions toward a negative classification, reinforcing the assay's strength as a non-invasive indicator of reduced cancer risk.
Figure 2.
SHAP summary plot illustrating feature importance in the predictive model for prostate cancer risk. This plot illustrates how each input variable influenced the model's output prediction relative to the baseline (expected value). The base value of 1.2 represents the model's expected prediction across the dataset, while the final output of 0.988 reflects the individualized prediction for the patient. Negative SHAP values (shown in red) decrease the predicted risk, whereas positive values (shown in yellow) increase it. In this example, a high PSA level contributed most to lowering the predicted risk (–0.141), while the PI-RADS slightly increased it (+0.086). Other features such as 4K score, age, and PSE had smaller marginal effects. This individualized explanation supports interpretability of the model’s output and reinforces trust in risk stratification.
Figure 2.
SHAP summary plot illustrating feature importance in the predictive model for prostate cancer risk. This plot illustrates how each input variable influenced the model's output prediction relative to the baseline (expected value). The base value of 1.2 represents the model's expected prediction across the dataset, while the final output of 0.988 reflects the individualized prediction for the patient. Negative SHAP values (shown in red) decrease the predicted risk, whereas positive values (shown in yellow) increase it. In this example, a high PSA level contributed most to lowering the predicted risk (–0.141), while the PI-RADS slightly increased it (+0.086). Other features such as 4K score, age, and PSE had smaller marginal effects. This individualized explanation supports interpretability of the model’s output and reinforces trust in risk stratification.
The consistency of feature importance rankings across different model architectures strengthens confidence in the biological relevance and clinical utility of the PSE assay. Furthermore, SHAP analysis revealed that the models maintained logical, clinically coherent relationships between input features and outcomes, avoiding erratic or biologically implausible patterns often seen with overfitted or poorly generalized models. This interpretability supports potential real-world adoption, as clinicians can better understand and trust model recommendations when they align with known prostate cancer risk factors. The combination of high model transparency, biological plausibility, and clinical relevance positions EpiSwitch PSE as a robust tool to enhance prostate cancer diagnostic workflows.
Table 2.
Performance of predictive models in identifying patients who could safely avoid transrectal or transperineal prostate biopsies. Performance comparison of two predictive models estimating which patients could safely avoid prostate biopsy based on EpiSwitch PSE results and clinical variables. Both models were applied to the same cohort of 134 patients. Model A classified only Gleason ≥3+4 as malignant, while Model B included Gleason 3+3. Biopsy avoidance rate and model accuracy are shown for each approach.
Table 2.
Performance of predictive models in identifying patients who could safely avoid transrectal or transperineal prostate biopsies. Performance comparison of two predictive models estimating which patients could safely avoid prostate biopsy based on EpiSwitch PSE results and clinical variables. Both models were applied to the same cohort of 134 patients. Model A classified only Gleason ≥3+4 as malignant, while Model B included Gleason 3+3. Biopsy avoidance rate and model accuracy are shown for each approach.
| Model |
Gleason score classified as malignant |
Total Patients Tested (n) |
Model Accuracy |
Patients Predicted to Avoid Biopsy (n) |
Biopsy Avoidance Rate (%) |
| Model A |
3+4 |
134 |
77.3% |
106 |
79.1 |
| Model B |
3+3 |
134 |
80.0% |
84 |
62.7 |
3.5. Cases Demonstrating Additional PSE Utility
Three illustrative case studies underscore the clinical utility of EpiSwitch PSE in informing prostate cancer management. In Case 1, a patient received a low-likelihood PSE result despite a suspicious PI-RADS 5 lesion observed via MRI. A subsequent MRI/TRUS fusion-guided biopsy was negative for prostate cancer, supporting the reliability of the PSE result and helping avoid overtreatment. In Case 2, the PSE test indicated a high likelihood of cancer, but due to the presence of a cardiac pacemaker, MRI was contraindicated. The urologist proceeded directly to biopsy, which confirmed clinically significant prostate cancer. In Case 3, a patient with a high-likelihood PSE result had a negative MRI; however, guided by the PSE result, the treating urologist and patient opted for a systemic 12-core biopsy. All 12 cores revealed Gleason 5+4=9 lesions, indicating aggressive disease that would have otherwise been missed by imaging alone. These cases demonstrate how PSE can complement or even override imaging findings, enhancing diagnostic confidence and enabling timely, personalized clinical decision-making.