Molecular Progression Risk Score for Prediction of Muscle Invasion in Primary T1 High-Grade Bladder Cancer

Background

Pathologic T1 high-grade (pT1HG) bladder cancer (BC) is characterized by a high progression rate and constitutes an important clinical challenge; however, there is no consensus on the prediction of progression in pT1HG BC. The purpose of this study was to validate previously published molecular progression risk score (MoPRS) for predicting muscle-invasive disease in pT1HG BC.

Materials and Methods

The expression of an 8-gene progression-related classifier identified from microarray data was analyzed by real-time PCR, and the MoPRS was calculated in 121 newly recruited patients with pT1HG BC. Progression was defined as muscle invasion or metastasis.

Results

Overall, the disease of 28 patients (23.1%) progressed to muscle-invasive BC during the median follow-up of 63.7 (interquartile range, 17.6-96.4) months. The MoPRS was significantly higher in 1973 World Health Organization grade 3 than grade 2 tumors (P = .004). Early development of invasive BC was more prevalent in the highest quartile MoPRS group than in the lowest to 75th percentile MoPRS groups according to Kaplan-Meier analysis. Multivariate Cox regression analysis revealed that the MoPRS was an independent predictor of invasive BC, either as a continuous variable (hazard ratio, 1.624; 95% confidence interval, 1.266-2.082; P < .001) or as a categorical variable (hazard ratio, 3.089; 95% confidence interval, 1.335-7.150; P = .008).

Conclusion

The MoPRS was an independent prognostic factor for identifying patients at high risk of invasive BC in patients with pT1HG BC. This scale may help identify patients who could benefit from more aggressive therapeutic intervention such as early cystectomy.