Risk estimation of multiple recurrence and progression of non muscle invasive bladder carcinoma using new mathematical models

Systematic review of methods used in prediction models with recurrent event data

BACKGROUND

Patients who suffer from chronic conditions or diseases are susceptible to experiencing repeated events of the same type (e.g. seizures), termed 'recurrent events'. Prediction models can be used to predict the risk of recurrence so that intervention or management can be tailored accordingly, but statistical methodology can vary. The objective of this systematic review was to identify and describe statistical approaches that have been applied for the development and validation of multivariable prediction models with recurrent event data. A secondary objective was to informally assess the characteristics and quality of analysis approaches used in the development and validation of prediction models of recurrent event data.

METHODS

Searches were run in MEDLINE using a search strategy in 2019 which included index terms and phrases related to recurrent events and prediction models. For studies to be included in the review they must have developed or validated a multivariable clinical prediction model for recurrent event outcome data, specifically modelling the recurrent events and the timing between them. The statistical analysis methods used to analyse the recurrent event data in the clinical prediction model were extracted to answer the primary aim of the systematic review. In addition, items such as the event rate as well as any discrimination and calibration statistics that were used to assess the model performance were extracted for the secondary aim of the review.

RESULTS

A total of 855 publications were identified using the developed search strategy and 301 of these are included in our systematic review. The Andersen-Gill method was identified as the most commonly applied method in the analysis of recurrent events, which was used in 152 (50.5%) studies. This was closely followed by frailty models which were used in 116 (38.5%) included studies. Of the 301 included studies, only 75 (24.9%) internally validated their model(s) and three (1.0%) validated their model(s) in an external dataset.

CONCLUSIONS

This review identified a variety of methods which are used in practice when developing or validating prediction models for recurrent events. The variability of the approaches identified is cause for concern as it indicates possible immaturity in the field and highlights the need for more methodological research to bring greater consistency in approach of recurrent event analysis. Further work is required to ensure publications report all required information and use robust statistical methods for model development and validation.

PROSPERO REGISTRATION

CRD42019116031.

Natural History of Multiple Recurrences in Intermediate-Risk Non-Muscle Invasive Bladder Cancer: Lessons From a Prospective Cohort

OBJECTIVE

To describe the risk of multiple recurrences in intermediate-risk non-muscle invasive bladder cancer (IR-NMIBC) and their impact on progression. Prognostic studies of IR-NMIBC have focused on initial recurrences, yet little is known about subsequent recurrences and their impact on progression.

MATERIALS AND METHODS

IR-NMIBC patients from the Be-Well Study, a prospective cohort study of NMIBC patients diagnosed from 2015 to 2019 at Kaiser Permanente Northern California, were identified. The frequency of first, second, and third intravesical recurrences of urothelial carcinoma were characterized using conditional Kaplan-Meier analyses and random-effects shared-frailty models. The association of multiple recurrences with progression was examined.

RESULTS

In 291 patients with IR-NMIBC (median follow-up 38 months), the 5-year risk of initial recurrence was 54.4%. After initial recurrence (n = 137), 60.1% of patients had a second recurrence by 2 years. After second recurrence (n = 70), 51.5% of patients had a third recurrence by 3 years. In multivariable analysis, female sex (Hazard Ratio 1.51, P< .01), increasing tumor size (HR 1.14, P< .01) and number of prior recurrences (HR 1.24, P< .01) were associated with multiple recurrences; whereas maintenance BCG (HR 0.66, P = .03) was associated with reduced recurrences. The 5-year risk of progression varied significantly (P< .01) by number of recurrences: 9.5%, 21.9%, and 37.9% for patients with 1, 2, and 3+ recurrences, respectively.

CONCLUSIONS

Multiple recurrences are common in IR-NMIBC and are associated with progression. Female sex, larger tumors, number of prior recurrences, and lack of maintenance BCG were associated with multiple recurrences. Multiple recurrences may prove useful as a clinical trial endpoint for IR-NMIBC.

A Comparison of the Anesthetic Methods for Recurrence Rates of Bladder Cancer after Transurethral Resection of Bladder Tumors Using National Health Insurance Claims Data of South Korea

Bladder cancers have high recurrence rates and are usually removed via transurethral resection of bladder tumor (TURBT). Recently, some reports showed that the anesthetic method may affect the recurrence rates of bladder cancers. The purpose of this population-based study was to compare the effect of anesthetic methods with the recurrence rates of bladder cancers in South Korea. A total of 4439 patients were reviewed retrospectively using the data of the Korean National Health Insurance (NHI) claims database from January 2007 to December 2011. Patients were divided into 2 groups who received general (n = 3767) and regional anesthesia (n = 582), and were followed up until September 2017. Propensity score matching was conducted to reduce the effect of confounding factors. After using propensity score matching with a multivariable Cox regression model, age (p < 0.001), sex (p < 0.001), hypertension (p = 0.003), diabetes mellitus (p = 0.001), and renal disease (p < 0.001) were significantly associated with bladder cancer recurrence. However, there were no significant differences in the recurrence rates of bladder cancers in patients who received general anesthesia and spinal anesthesia for TURBTs. This study revealed that there is no relationship between the anesthetic method and bladder cancer recurrence. Either general anesthesia or regional anesthesia can be used depending on the situation in patients receiving TURBT. Future prospective studies are warranted to confirm the association between the anesthetic method and the recurrence rates of bladder cancer.

Multiple recurrences and risk of disease progression in patients with primary low-grade (TaG1) non-muscle-invasive bladder cancer and with low and intermediate EORTC-risk score

AIM

To assess the prognostic value of multiple recurrences on the risk of progression in a large cohort of TaG1 bladder cancer of low and intermediate risk based on the EORTC score and to evaluate prognostic factors of multiple recurrences.

MATERIALS AND METHODS

We retrospectively analyzed a French cohort of 470 patients with primary TaG1 bladder cancer diagnosed between 1986 and 2010 and followed until 2012. They were classified at low and intermediate risk using the EORTC risk score. Associations between the number of recurrences and the risk of progression to high grade Ta/T1 bladder cancer and progression to muscle-invasive disease were assessed. The characteristics of recurrences, as occurrence time or localization, and risk of other recurrences were evaluated.

RESULTS

Out of 470 patients, 251 had recurrence, 34 progressed to high grade Ta/T1 and 17 to muscle-invasive disease, including 4 who had non muscle-invasive progression first. The median follow-up was 7.2 years (interquartile range: 4.2-10.9). In half the progressions, no previous recurrence was observed. No association between the number of recurrences and the risk of progression was detected. Even after 5 years free of event, patients had a 15% risk of recurrence. History of two or more recurrences increased by 4.5 the risk of subsequent recurrence. Time between two recurrences inferior to six months and multifocal localization increased the risk of recurrence.

CONCLUSION

Surveillance of patients with TaG1 should be continued beyond 5 years of follow-up. However, cystoscopy exams could be spaced after 5 years. Multiple TaG1 recurrences did not appear to be prognostic for disease progression, but increased significantly the risk of subsequent recurrences. Short time between two recurrences and multifocal localization may serve to adapt monitoring of patients with TaG1 Bladder cancer.