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The following is a summary of “Prognostic factors for refractory outcome in localizing TIO: experience in a tertiary center,” published in the January 2025 issue of Endocrinology by Hoong et al.
Tumor-induced osteomalacia (TIO), a paraneoplastic disorder characterized by renal phosphate wasting, cured by tumor removal; however, some cases remain refractory to surgery, leading to significant long-term health issues.
Researchers conducted a retrospective study to identify risk factors linked to refractory outcomes.
They assessed 44 individuals diagnosed with TIO from 1998 to 2023, all undergoing targeted intervention after successful tumor localization. The cure was defined as sustained normophosphatemia without supplementation for over 1 month, confirmed at the last follow-up.
The results showed 29 individuals achieved a cure, while 15 had a refractory outcome. On univariate Cox regression, the HR for predicting cure was 3.43 (95% CI 1.45–8.11, P =0.005) for individuals diagnosed after 2013 compared to earlier diagnoses, and 2.56 (95% CI 1.20–5.45, P =0.015) for those with negative surgical tumor margins compared to positive/unspecified margins. After adjusting for the year of diagnosis, tumors originating from soft tissue (HR 2.72 versus bone, 95% CI 1.22–6.09, P =0.015) or located outside the spine (HR 0.22 for spine vs non-spine, 95% CI 0.05–0.96, P =0.043) had a higher likelihood of cure. Tumor size, age, gender, and baseline biochemistry (including FGF23, phosphorus, 1,25-dihydroxyvitamin D [1,25(OH)2 D], and ALP) were not predictive of cure. Post-procedural FGF23 was the most reliable biochemical marker of cure (area under the curve [AUC] 0.899, 95% CI 0.764–1.00, P <0.001).
Investigators concluded that complete tumor resection with clear margins within the past decade was associated with improved prognosis in patients with tumoral osteomalacia, while baseline biochemistry was not predictive of cure, and bone or spinal tumor locations were associated with a higher risk of refractory disease.
Source: academic.oup.com/jcem/advance-article-abstract/doi/10.1210/clinem/dgae911/7943416