Bone metastases are common in genitourinary cancers, but they are underreported and not well researched.

Synchronous bone metastases occur in 1.39–5.5% of bladder cancer patients, while 30–40% of cases are metachronous.

Bone morphogenetic proteins (BMPs) play a key role in regulating proliferation, migration and invasion of tumor cells in bone microenvironment of bone metastases from metastatic urothelial carcinoma (mUC).

Bone metastases represent a poor prognostic factor due to high morbidity and mortality correlated to skeletal-related events (SREs). The incidence rate of SREs in bladder, renal pelvis, and ureteral cancer varies from 39 to 68%. Radiotherapy is the most frequent treatment for SREs. The early use of bone targeted therapies (BTT), zoledronic acid and denosumab, improves SREs incidence and morbidity and it seems to improve overall survival (OS).

To date, several new agents (immunotherapy and targeted drugs) demonstrated efficacy in mUC. However, subgroup analysis for bone metastases is often not available, due to difficulties in analysing bone samples, non-RECIST lesions and delay in systemic treatment due to SREs that limit the enrolment of bone mUC patients in clinical trials. Larger solid tumor studies that included UC patients are the main source of data for the management of mUC patients with bone metastases.

For these patients, multidisciplinary approach should be preferred, involving orthopaedics, radiotherapists and rehabilitation to improve outcome and quality of life. New prospective trials should characterize clinical and molecular features of patients with bone metastases and the impact of new drugs on this poor prognostic metastatic site.

骨转移在泌尿生殖系统癌症中很常见，但它们的报道不足且研究不足。

同步性骨转移发生在 1.39-5.5% 的膀胱癌患者中，而 30-40% 的病例是异时性的。

骨形态发生蛋白 (BMP) 在调节转移性尿路上皮癌 (mUC) 骨转移骨微环境中肿瘤细胞的增殖、迁移和侵袭中起关键作用。

由于与骨骼相关事件 (SRE) 相关的高发病率和死亡率，骨转移代表不良预后因素。膀胱癌、肾盂癌和输尿管癌中 SRE 的发生率从 39% 到 68% 不等。放射治疗是 SRE 最常见的治疗方法。早期使用骨靶向疗法 (BTT)、唑来膦酸和狄诺塞麦可提高 SRE 的发生率和发病率，并且似乎可以提高总生存率 (OS)。

迄今为止，几种新药（免疫疗法和靶向药物）在 mUC 中显示出疗效。然而，由于难以分析骨样本、非 RECIST 病变以及由于限制骨 mUC 患者参与临床试验的 SRE 导致的全身治疗延迟，通常无法进行骨转移的亚组分析。包括 UC 患者在内的大型实体瘤研究是管理 mUC 骨转移患者的主要数据来源。

对于这些患者，应首选多学科方法，包括骨科、放射治疗师和康复治疗，以改善预后和生活质量。新的前瞻性试验应该表征骨转移患者的临床和分子特征，以及新药对这种预后不良的转移部位的影响。