Duration of Parathyroid Function Recovery in Patients With Protracted Hypoparathyroidism After Total Thyroidectomy for Papillary Thyroid Carcinoma

Abstract

PurposeThe aim of the present study is to investigate the time to recovery of parathyroid function in patients with protracted hypoparathyroidism at 1 month after total thyroidectomy of papillary thyroid carcinoma.Materials and MethodsAdult patients who underwent total thyroidectomy for papillary thyroid cancer were included. Cases of long-term hypoparathyroidism were studied for recovery of parathyroid function during the follow-up. The duration of recovery and associated variables were recorded.ResultsOut of the 964 patients, 128 (13.28%) developed protracted hypoparathyroidism and of these, 23 (2.39%) developed permanent hypoparathyroidism and 105 (10.89%) recovered: 86 (8.92%) before 6 months, 11 (1.14%) within 6 and 12 months and 8 (0.83%) after 1 year follow-up. Variables significantly associated with the time to parathyroid function recovery were number of autotransplanted parathyroid glands (HR, 1.399; 95% CI, 1.060 – 1.846; P = 0.018), serum calcium concentration >2.07 mmol/L (Hazard ratio [HR], 1.628; 95% confidence interval [CI], 1.009 – 2.628; P = 0.046) and PTH level > 1.2 pmol/L (HR, 1.702; 95% CI, 1.083 – 2.628; P = 0.021) at 1 month postoperatively.ConclusionPermanent hypoparathyroidism should not be diagnosed easily by time, since up to one-fifth of the patients will experience recovery after a period of 6 months and a few patients even beyond one year. The number of autotransplanted parathyroid glands is positively associated with the time to parathyroid function recovery.

Selective Parathyroid Autotransplantation During Total Thyroidectomy for Papillary Thyroid Carcinoma: A Cohort Study

“…El-Sharaky et al found that post-operative parathyroid function of autotransplanted PGs would gradually recover from the 2nd week to a normal level at the 4th week, following blood tests and electron microscopy analysis ( 27 ). Qiu et al found, out of the 964 patients, 23 (2.39%) developed permanent hypoparathyroidism and 105 (10.89%) recovered: 86 (8.92%) before 6 months, 11 (1.14%) within 6 and 12 months and 8 (0.83%) after 1 year follow-up; number of autotransplanted parathyroid glands (hazard ratio, 1.399; 95% CI, 1.060–1.846; P = 0.018) was significantly associated with the time to parathyroid function recovery ( 28 ). Promberger et al found serum PTH concentrations in patients with 2 PGs autotransplanted recovered to 108% of the baseline levels at 6-month follow-up ( 29 ).…”

Parathyroid hormone of ≥1.6 pmol/L at 6 months is associated with recovery in ‘long-term’ post-surgical hypoparathyroidism

“…Adjusted calcium is not likely to be a reliable predictor of late recovery as the extent of treatment is likely to influence adjusted calcium levels and there is controversy over whether patients should be under treated (parathyroid stimulation) or adequately treated (parathyroid splinting) to facilitate recovery. None of these studies ( 4 , 18 , 23 ) have reported on the predictive value of biochemical markers (including PTH) at the defined threshold for long-term PoSH (around 6–12 months) to provide a comparison for our findings.…”

“…A recent Chinese study (2021) reported on a large cohort of patients with papillary cancer ( n = 968); 42 of whom had PoSH at 6 months. They demonstrated late recovery of function in 19 patients ( n = 11 between 6–12 months and n =8 after 1 year), compared to 23 patients who remained dependent on supplements ( 23 ). In patients where recovery was late, the longest recovery time has not been clearly reported in these studies.…”

“…An adjusted calcium at 1 month of >2.25 mmol/L has been reported as a predictor of late recovery in two studies ( 4 , 18 ). In contrast, the study from China suggested a much lower cut-off of >2.07 mmol/L to predict the same outcome ( 23 ). This study, in contrast, shows that there was no difference in calcium levels between those with late recovery and ongoing PoSH at any point within first 6 months.…”

“…It is also worth mentioning here that the rate of recovery of parathyroid function could vary among various clinicians and plausibly higher when more aggressive strategies to wean off supplements are employed. The term ‘recovery of parathyroid function’ may be controversial but refers to the ability to wean patients off calcium and/or active vitamin D supplements without precipitating symptoms of hypoparathyroidism or a significant fall in calcium and/or PTH levels ( 4 , 18 , 23 ). While the study included all patients at risk of PoSH after thyroid surgery over a 10-year period, the number of patients with 6 months PoSH is still relatively small.…”