Secondary bladder cancer after upper tract urothelial carcinoma in the US population

Study Type – Prognosis (cohort) Level of Evidence 2a What's known on the subject? and What does the study add? It is known that a certain percentage of patients treated for upper tract urothelial carcinoma (UTUC) will go on to develop a secondary bladder cancer; however, the risk factors for developing a secondary bladder tumour have not been studied in a population‐based setting. Given the large changes in how UTUC has been diagnosed and managed in recent years, this study aimed to evaluate the natural history of UTUC in the US population over a 30‐year period, with a particular emphasis on the development of secondary bladder cancer.

OBJECTIVE

• ? To assess the natural history of upper tract urothelial carcinoma (UTUC) and the development of lower tract secondary cancer.

PATIENTS AND METHODS

• ? Patients diagnosed with UTUC between 1975 and 2005 were identified within nine Surveillance, Epidemiology and End Results registries.
• ? Baseline characteristics of patients with and without secondary bladder cancer were compared.
• ? A multivariate logistic regression model was fitted to test if the year of diagnosis predicted the likelihood of developing a secondary bladder cancer.

RESULTS

• ? Of the 5212 patients with UTUC, 242 (4.6%) had a secondary bladder cancer (range: 1.7–8.2%).
• ? There was a mean interval of 26.5 (95% CI: 22.2–30.8) months between cancer diagnoses.
• ? Compared with those without secondary tumours, patients with secondary bladder malignancy were more likely to present with larger tumours (4.2 vs 3.1 cm, P < 0.001) and with tumours located in the ureter (P < 0.001).
• ? Year of diagnosis was not a predictor of the likelihood of having a secondary bladder malignancy in a multivariate analysis controlling for demographic and tumour characteristics (odds ratio: 0.99; 95% CI: 0.95–1.03)

CONCLUSIONS

• ? Patients with larger urothelial tumours located in the ureter were those most likely to develop a secondary lower tract tumour.
• ? No longitudinal changes in the rate of secondary bladder cancer were noted among patients with UTUC over the 30‐year study period.