Cancer and All-Cause Mortality in Bladder Cancer Patients Undergoing Radical Cystectomy: Development and Validation of a Nomogram for Treatment Decision-Making: Beyond the Abstract

Our study provides one of the largest cohorts to assess competing risks using large population-based data. Surveillance, Epidemiology, and End Results (SEER) alone data (without claims-based information) does not provide comorbidity information, which is a significant limitation when interpreting survival outcomes and extrapolating those data into predictive tools. The National Cancer Data Base lacks the generalizability of findings as those data are often derived from dedicated cancer centers which have inherent selection biases. Using the SEER and Texas Cancer Registry (TCR)-Medicare linked-databases, we were able to leverage the power of the largest insurance provider in the United States (Medicare) with one of the largest cancer registries to develop and validate a nomogram, which has been converted into an on-line calculator called the Radical Cystectomy Survival Calculator© (RCSC). The RCSC calculator provides a benefit-risk assessment for patients considering radical cystectomy. Next steps include multi-institutional validation of the nomogram as well as RCSC assessment in the clinic as a decision-aid tool.

Brief summary of our findings:

Bladder cancer represents a lethal disease once it invades the muscle. Treatments include radical cystectomy which is associated with a non-negligible risk of morbidity and all-cause mortality. These concerns, as well as prior reports concerning underuse due to advanced age and increased comorbidities, suggest cancer-specific as well as all-cause mortality rates. Taking these determinants, as well as tumor-related factors, into account should be incorporated into patient counseling and guideline recommendations.

A total of 5,325 and 1,257 diagnosed with clinical stage T2-T4a muscle-invasive bladder cancer from January 1, 2006 to December 31, 2011 from SEER-Medicare (discovery cohort) and Texas Cancer Registry (TCR)-Medicare (validation cohort) linked-data, respectively. Cox proportional hazards models were used and a nomogram was developed to predict 3- and 5-year overall and cancer-specific survival with external validation.

In the discovery cohort, older age at diagnosis (>80 vs 66-69 years old, HR 1.63; 95% CI, 1.47 to 1.81, p<0.001), higher comorbidity (Charlson comorbidity index 3+ vs 0, HR 1.68; 95% CI, 1.53-1.85, p<0.001) and non-Hispanic black vs. white patients (HR 1.28; 95% CI, 1.12 to 1.45, p<0.001) were associated with decreased overall survival. Similar findings for cancer-specific survival persisted. A nomogram developed using SEER-Medicare data, predicted 3- and 5-year overall and cancer-specific survival rates with concordance indices of 0.65 and 0.66 in the validated TCR-Medicare cohort, respectively.

Written by: Stephen B. Williams, The University of Texas Medical Branch

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