Nomogram Shows Prognostic Utility for Prediction of OS in MIBC

A recent study sought to determine if a previously developed nomogram predictive of pathologic lymph node metastasis after multiagent chemotherapy for clinical node-negative muscle-invasive bladder cancer (MIBC) may also predict overall survival (OS) in patients treated with definitive chemoradiotherapy (CRT). The results were presented at the American Society for Radiation Oncology 2023 Annual Meeting.

A total of 1047 patients with cN0 MIBC who were treated with definitive CRT between 2004 and 2020 were identified using the National Cancer Database. Patient probability of occult nodal disease was assessed using a previous nomogram developed from those treated with multiagent chemotherapy alone followed by pathologic nodal assessment. After a 70:30 training and testing data split, variables were assessed for association with OS using a log-rank test.

Patients with P<.05 were deemed eligible for inclusion within a multivariate Cox proportional hazards model. Patients were then categorized as high-, medium-, or low-risk for death using the model’s prognostic index.

The median age of the patient cohort was 78 years, and median follow-up was 31.3 months. Cox analysis revealed that patient age (hazard ratio [HR], 1.03; 95% CI, 1.02-1.04; P<.001), Charlson-Deyo score, and predicted probability of developing future lymphadenopathy (HR, 4.47; 95% CI, 1.83-10.93; P=.001) were significantly associated with OS.

The median OS for patients identified as having a high, medium, or low risk for death on Cox analysis was 34.2 months (interquartile range [IQR], 21.3-40.6 months), 38.9 months (IQR, 31.4-47.2 months), and 77.8 months (IQR, 56.1-100.3 months), respectively (area under the curve [AUC] range, 0.615-0.870); P<.001). Similar outcomes were seen in the testing cohort, with significant differences between median OS across each group (AUC range, 0.580-0.726; P<.001).

Among patients in the institutional cohort, only 1 patient who was stratified as high (n=1/2; 50.0%) or medium risk (n=0/5; 0.0%) remained alive at time of final follow-up, while 88.9% (n=7/8) of low-risk patients survived (P=.051). Significant differences in OS were again seen between risk groups, with a median OS of 51.3 months and 19.9 months for high- and medium-risk patients, respectively. A median OS for low-risk patients was not reached (P=.006).

The previously reported nomogram has a prognostic utility for the prediction of OS. Further research is needed to determine how radiation and chemotherapy may offset worse OS in patients who are at high risk for occult nodal disease progression.