Objective

To compare the negative predictive value (NPV) of multiparametric MRI for Gleason score (GS) ≥ 3+4 cancer and evaluate predictors of these tumors in men with suspected disease and under active surveillance (AS).

Materials and methods

This retrospective study included 38 men with suspected prostate cancer and 38 under AS with scans assigned PI-RADS v2 scores 1 or 2 between May 2016 and September 2017. Biopsy results were no cancer, GS = 3+3, or GS ≥ 3+4. Pre-MRI PSA, gland volume, and PSA density were recorded. Chi-square, equality of proportions, and logistic regressions were used to analyze the data.

Results

Intermediate to high-grade cancer was found in 12.8% (95% CI = 2.3-23.3) and 35.9% (95% CI = 20.8-50.9) of men with suspected cancer, and under AS (p = 0.02), respectively. The NPV for GS ≥ 3+4 were 87.2% (suspected cancer; 76.7-97.7) and 64.1% (AS; 49.0-79.2). In neither group PSA significantly predicted cancer grade (p = 0.75 and 0.63). Although it did not reach conventional statistical significance, PSA density was a good predictor of cancer grade in men with suspected disease (p = 0.06), but not under AS (p = 0.62).

Conclusion

The NPV of multiparametric MRI for GS ≥ 3+4 is higher in men with suspected prostate cancer than in men under AS. PSA density ≤ 0.15 improved the prediction of intermediate to high-grade disease in patients without known cancer.

Background

Reducing surgical supply costs can help to lower hospital expenditures. We aimed to evaluate whether variation in supply costs between urologic surgeons performing both robotic or open partial nephrectomies is associated with differential patient outcomes.

Methods

In this retrospective cohort study, we reviewed 399 consecutive robotic (n=220) and open (n=179) partial nephrectomies performed at an academic center. Surgical supply costs were determined at the institution-negotiated rate. Through retrospective review, we identified factors related to case complexity, patient comorbidity, and perioperative outcomes. Two radiologists assigned nephrometry scores to grade tumor complexity. We created univariate and multivariable models for predictors of supply costs, length of stay, and change in serum creatinine.

Results

Median supply cost was $3,201 [interquartile range (IQR): $2,201-3,808] for robotic partial nephrectomy and $968 (IQR: $819-1,772) for open partial nephrectomy. Mean nephrometry score was 7.0 (SD =1.7) for robotic procedures and 8.2 (SD =1.6) for open procedures. In multivariable models, the surgeon was the primary significant predictor of variation in surgical supply costs for both procedure types. In multivariable mixed-effects analysis with surgeon as a random effect, supply cost was not a significant predictor of change in serum creatinine for robotic or open procedures. Supply cost was not a statistically significant predictor of length of stay for the open procedure. Supply cost was a significant predictor of longer length of stay for the robotic procedure, however it was not a clinically meaningful change in length of stay (0.02 days per $100 in supply costs).

Conclusions

Higher supply spending did not predict significantly improved patient outcomes. Variability in surgeon supply preference is the likely source of variability in supply cost. These data suggest that efforts to promote cost-effective utilization and standardization of supplies in partial nephrectomy could help reduce costs without harming patients.