Risk factors and nomogram for newly diagnosis of bone metastasis in bladder cancer: A SEER-based study

Bladder cancer (BC) is the second most common urogenital malignant tumor. Bone metastasis (BM) is not common in BC patients, and there are only few studies on it. However, it was found in a clinical study that BM was related to the occurrence of bone complications and the decrease in survival rate. Early diagnosis of BC with BM is important for timely intervention and prevention of pathological fracture, which is of great significance for improving the quality of life of BC patients. This study aimed to identify the risk factors of BM and establish a predictive nomogram for the early diagnosis of BM in BC. The medical records of the newly diagnosed BC patients were extracted from the database of Surveillance, Epidemiology, and End Results (SEER) during 2010 to 2016. The risk factors of BC with BM were evaluated using multivariate logistic regression analysis. Then a nomogram was established to predict the risk of BC with BM. This study included 35,506 patients identified in the SEER database as diagnosed with BC, 796 of whom had BM. Grade, T stage, N stage, liver metastasis, race, brain metastasis, lung metastasis, histologic type, primary site, and age were risk predictors of BC with BM. Using Harrell's concordance index, calibration curve, and decision curve analyses, we found that the nomogram for predicting the risk of BC metastasis performed well internally. The nomogram developed in this study is expected to become an accurate and personalized tool for predicting risks of BC with BM in patients. It may be of great significance for clinicians to formulate more reasonable and effective treatment strategies. As the first study, we established a predictive nomogram for BC with BM based on the retrospective analysis of data of BC patients from the SEER database.