Departments of Urology and Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
Study Type - Prognosis (individual cohort) Level of Evidence 2b.
What's known on the subject? and What does the study add? We know that patient fitness for surgery is a major predictor of morbidity and mortality after surgery. We found the published nomogram did not incorporate several known clinical risk factors and its predictive value was only slightly better than using the patient's age and Charlson score to predict perioperative morality. This limitation may be related to the lack of availability of these factors in national databases for inclusion when creating a nomogram. In addition, there are elements that factor into postoperative patient care that are not easily measured, such as hospital-stay pathways, ancillary staff expertise, supportive medical care, and surgeon ability.
To evaluate the performance of the Isbarn nomogram for predicting 90-day mortality following radical cystectomy in a contemporary series.
We identified 1141 consecutive radical cystectomy patients treated at our institution between 1995 and 2005 with at least 90 days of follow-up. We applied the published nomogram to our cohort, determining its discrimination, with the area under the receiver operating characteristic curve (AUC), and calibration. We further compared it with a simple model using age and the Charlson comorbidity score.
Our cohort was similar to that used to develop the Isbarn nomogram in terms of age, gender, grade and histology; however, we observed a higher organ-confined (≤pT2, N0) rate (52% vs 24%) and a lower overall 90-day mortality rate [2.8% (95% confidence interval 1.9%, 3.9%) vs 3.9%]. The Isbarn nomogram predicted individual 90-day mortality in our cohort with moderate discrimination [AUC 73.8% (95% confidence interval 64.4%, 83.2%)]. In comparison, a model using age and Charlson score alone had a bootstrap-corrected AUC of 70.2% (95% confidence interval 67.2%, 75.4%).
The Isbarn nomogram showed moderate discrimination in our cohort; however, the exclusion of important preoperative comorbidity variables and the use of postoperative pathological stage limit its utility in the preoperative setting. The use of a simple model combining age and Charlson score yielded similar discriminatory ability and underscores the significance of individual patient variables in predicting outcomes. An accurate tool for predicting postoperative morbidity/mortality following radical cystectomy would be valuable for treatment planning and counselling. Future nomogram design should be based on preoperative variables including individual risk factors, such as comorbidities.
Written by:
Taylor JM, Feifer A, Savage CJ, Maschino AC, Bernstein M, Herr HW, Donat SM. Are you the author?
Reference: BJU Int. 2011 Jul 1. Epub ahead of print.
doi: 10.1111/j.1464-410X.2011.10391.x
PubMed Abstract
PMID: 21722291
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