Purpose: Hypocalcemia is the most common complication following thyroidectomy. We investigated the frequency and risk factors of hypocalcemia after total thyroidectomy in pediatric patients with thyroid cancer.
Methods: This retrospective study inclu...
Purpose: Hypocalcemia is the most common complication following thyroidectomy. We investigated the frequency and risk factors of hypocalcemia after total thyroidectomy in pediatric patients with thyroid cancer.
Methods: This retrospective study included 98 patients, diagnosed with thyroid cancer after total thyroidectomy <20 years of age during 1990―2018 and followed up more than 2 years at Seoul National University Hospital. Oral calcium and active vitamin D (1-hydroxycholecalciferol or 1,25-dihydroxycholecalciferol) were prescribed when postoperative calcium level was lower than 8.0 mg/dL and when a patient complained of hypocalcemic symptoms. Postoperative hypocalcemia was defined as requiring active vitamin D supplementation to maintain blood calcium levels above 8.5 mg/dL following surgery.
Results: The study included 27 boys (27.6%) and 71 girls (72.4%). The mean age at diagnosis was 14.9 ± 3.7 years. Hypocalcemia occurred in 43 (43.9%) patients. Twenty-one (21.4%) patients discontinued active vitamin D less than 6 months, and 14 (14.3%) continued active vitamin D for more than 2 years. Tumor multifocality (Odds ratio (OR) 3.7 vs. single tumor, P=0.013) and preoperative calcium levels (OR 0.2, P=0.028) were independent predictors for developing hypocalcemia immediately after total thyroidectomy. In addition, age (OR 0.8, P=0.011) and preoperative calcium levels (OR 0.04, P=0.014) significantly decreased the risk for persistent hypocalcemia requiring active vitamin D for more than 2 years.
Conclusion: Hypocalcemia occurred in about two-fifth after total thyroidectomy in pediatric thyroid cancer. Among them, one-third of patients continued active vitamin D medication for more than 2 years, which was predicted by young age and low preoperative calcium levels.