Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome. It is curable by excision of the causative tumor. However, a few cases may persist or relapse after tumor resection. We aimed to investigate the rate of these events and related factors. We retrospectively studied TIO patients treated with surgery in a tertiary hospital. TIO was established based on a pathologic examination or the reversion of hypophosphatemia. Refractory TIO patients consisted of those with nonremission or recurrent hypophosphatemia after surgery. A total of 230 patients were confirmed as having TIO. After primary surgery, 26 (11.3%) cases persisted, and 16 (7.0%) cases recurred. The overall refractory rate was 18.3%. The median time of recurrence was 33 months. Compared with patients in the recovery group, patients in the refractory group were more likely to be female (59.5% versus 41.0%, p = .029) and have a lower serum phosphate level (0.44 ± 0.13 versus 0.50 ± 0.11 mmol/L, p = .002). The refractory rate was lowest in head/neck tumors (7.5%) and highest in spine tumors (77.8%). Regarding the tissue involved of tumor location, the refractory rate was higher in tumors involving bone than tumors involving soft tissue (32.7% versus 7.0%, p < .001). The outcomes of malignant tumors were worse than those of benign tumors (p < .001): nonremission rate, 21.4% versus 9.7%; recurrence rate, 28.6% versus 6.5%. In the multivariate regression analysis, female sex, spine tumors, bone tissue-involved tumors, malignancy, and low preoperation serum phosphorus levels were identified as risk factors for refractory outcomes. High preoperative fibroblast growth factor 23 (FGF23) levels were also associated with refractory after adjusting for involving tissue and tumor malignancy. In summary, we are the first to report the rate and clinical characteristics of refractory TIO in a large cohort. For patients with multiple risk factors, especially spine tumors, clinical practitioners should be aware of a poor surgical prognosis. © 2019 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.

中文翻译：

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非缓解和复发性肿瘤诱发的骨软化症：一项回顾性研究。

肿瘤性骨软化症（TIO）是一种罕见的副肿瘤综合征。通过切除致病性肿瘤可以治愈。但是，少数病例在肿瘤切除后可能会持续或复发。我们旨在调查这些事件的发生率和相关因素。我们回顾性研究了三级医院接受手术治疗的TIO患者。根据病理检查或低磷血症的恢复建立TIO。难治性TIO患者由术后无缓解或复发性低磷血症的患者组成。总共有230名患者被确诊患有TIO。初次手术后，持续26例（11.3％），复发16例（7.0％）。总耐火率为18.3％。中位复发时间为33个月。与康复组患者相比，难治组患者中女性更可能为女性（59.5％对41.0％，p = .029），血清磷酸盐水平较低（0.44±0.13对0.50±0.11 mmol / L，p = .002）。头颈部肿瘤的顽固性最低（7.5％），脊柱肿瘤的顽固性最高（77.8％）。关于涉及肿瘤定位的组织，涉及骨的肿瘤的难治性率高于涉及软组织的肿瘤的难治性（32.7％对7.0％，p <.001）。恶性肿瘤的结局要比良性肿瘤差（p <.001）：未缓解率分别为21.4％和9.7％；未缓解率分别为21.4％和9.7％。复发率分别为28.6％和6.5％。在多元回归分析中，女性，脊柱肿瘤，骨组织相关肿瘤，恶性肿瘤和术前血清磷水平低被确定为顽固性结局的危险因素。调整组织和肿瘤恶性程度后，术前高成纤维细胞生长因子23（FGF23）水平也与难治性疾病相关。总而言之，我们是第一个报告大型队列中难治性TIO的发生率和临床特征的人。对于具有多种危险因素的患者，尤其是脊柱肿瘤，临床医生应注意手术预后不良。©2019作者。美国骨与矿物质研究学会出版的《骨与矿物质研究杂志》。临床医生应注意手术预后不良。©2019作者。美国骨与矿物质研究学会出版的《骨与矿物质研究杂志》。临床医生应注意手术预后不良。©2019作者。美国骨与矿物质研究学会出版的《骨与矿物质研究杂志》。