Methods
non-primary bladder malignancy, cancer, tumour
CANCER, TUMOUR
The Surveillance, Epidemiology, and End Results (SEER) database (2004–2015) which consists of seventeen different registries, lastly updated in November 2021 was used for this research. The SEER*Stat statistical software was used to select patients meeting the study criteria. A systematic search was performed to identify patients, who were diagnosed with T1 NMIBC between 2004 and 2015, in accordance with the 6The available data included information on the patient’s sociodemographics, tumour histopathological (e.g. T category, grading) and clinical characteristics (e.g. tumour size, location, history of the previous tumour defined as non-primary bladder malignancy), a therapy used (e.g. surgery type, chemotherapy) and survival outcomes (cancer and all-cause mortality during the follow-up). The 5-year OS and CSS was calculated for patients with sufficient follow-up as previously reported [The dataset was divided into training and validation cohorts in the proportion of 70 to 30. Group characteristics are presented in the respective table with the number of patients and percentage for categorical variables and medians, accompanied by the interquartile range (IQR) for continuous variables.