Predicting the probability of 90-day survival of elderly patients with bladder cancer treated with radical cystectomy

Abstract

Purpose: Despite the increased morbidity and mortality of radical cystectomy in elderly individuals with bladder cancer numerous studies show that surgery can provide a survival benefit. We sought to better identify patients at substantial risk for postoperative mortality.

Materials and methods: We evaluated 220 consecutive patients 75 years old or older treated with radical cystectomy for bladder cancer at a single institution from 2000 to 2008. The analytical cohort comprised 169 patients with complete preoperative data available. A Cox proportional hazards model was used to determine the value of precystectomy clinical information to predict 90-day survival after radical cystectomy. Results were used to create a nomogram predicting the probability of 90-day survival after radical cystectomy. The model was then subjected to 200 bootstrap resamples for internal validation.

Results: Of the 220 patients 28 (12.7%) died within 90 days of surgery. Older age (HR 2.30, 95% CI 1.22-4.32) and lower preoperative albumin (HR 2.50, 95% CI 1.40-4.45) were significant predictors of 90-day mortality. We developed a nomogram based on patient age, clinical stage, Charlson comorbidity index and albumin to predict the likelihood of 90-day mortality with 75% accuracy. Internal validation showed a bootstrap adjusted concordance index of 71%.

Conclusions: We developed a nomogram that provides individualized risk estimations to predict the probability of 90-day mortality, potentially enhancing preoperative counseling and providing clinicians with an added tool to individualize treatment decisions in this challenging patient population. These data suggest that albumin is a strong predictor of postoperative mortality and show the importance of assessing this variable before surgery.

Figure 1

Kaplan-Meier analysis of mortality up to 90 days from surgery in patients 80 years and older compared to those under 80 years of age (log rank p<0.0039).

Figure 2

Kaplan-Meier analysis of mortality up to 90 days from surgery in patients with a preoperative serum albumin >3.7 g/dL compared to those with an albumin ≤3.7 g/dL (log rank p=0.0032).

Figure 3

Preoperative nomogram predicting 90-day mortality in patients ≥75 years of age undergoing radical cystectomy. Points are calculated independently for each of the four variables (“contributed points”), and the sum of the points (“total points”) is used to calculate the 90-day survival probability. For example, an 83 year-old patient with muscle-invasive cancer, CCI of 2, and preoperative albumin of 2.9 g/dL (100 points) would have a 90-day survival probability of 50%.