High Parathyroid Hormone Rather than Low Vitamin D Is Associated with Reduced Event-Free Survival in Childhood Cancer.

Background: Vitamin D deficiency is linked to poor cancer outcomes but the impact of its consequence, elevated parathyroid hormone (PTH), remains understudied. PTH receptor activation influences cancer progression in vitro, yet the effect of elevated PTH on pediatric cancer survival is unexamined.

Methods: This retrospective study examines associations between PTH, 25-OH vitamin D (25OHD), and event-free survival (EFS) and overall survival (OS) in patients with pediatric cancer. Laboratory data from 4,349 patients (0-18 years) at a tertiary pediatric cancer unit were analyzed for the highest PTH and lowest 25OHD levels at diagnosis and the following 5 years. Data on relapse, secondary malignancies, and mortality were stratified by PTH levels above/below the cohort median (47 pg/mL) and 25OHD levels ≤30 nmol/L. EFS and OS were analyzed and hazard ratios (HR) were calculated for the entire cohort and six cancer subgroups.

Results: PTH and 25OHD values were available for 1,286 patients (731 male). Higher PTH associated with inferior EFS in primary malignant brain tumors [HR, 1.80 (1.19-2.72)], embryonal malignancies [HR, 2.20 (1.1-4.43)], and lymphatic malignancies [HR 1.98 (1.05-3.72)]. Vitamin D deficiency associated with inferior EFS in embryonal malignancies [HR 2.41 (1.24-4.68)]. In a multivariate Cox model, only higher PTH remained significant for inferior EFS.

Conclusions: Elevated PTH may indicate adverse outcomes in certain pediatric cancers.

Impact: This study identifies elevated parathyroid hormone as a potential marker for poor outcomes in patients with pediatric cancer, emphasizing the need for adequate vitamin D and calcium management.