Cohort review of patients with parathyroid cancer in End Stage Renal Disease (ESRD).

Background and hypothesis: Parathyroid carcinoma (PTTC) is a rare malignant endocrine tumor seen in up to 1-2% of all cases of primary hyperparathyroidism. However, incidence of parathyroid carcinoma in renal hyperparathyroidism is a rare phenomenon. We aimed to evaluate the outcomes of PTTC in renal hyperparathyroidism published in the literature.

Methods: Cohort review of parathyroid cancer cases reported in Medline (via PubMed), COCHRANE and EMBASE between the period 1985 - 2023 in patients with renal hyperparathyroidism.

Results: A total of 48 patients (20 M: 28F), with a mean age of 49.8 (± 11.7 SD: range 20-75) years. Dialysis vintage was for a period of 8.9 (± 7.2; range 6 months to 40 years). The mean preoperative values were as follows: serum corrected calcium-2.87 IQR 2.56-3.01), PTH - 221.8 (IQR 86.6 -257.2 pmol/L) and serum phosphate - 2.07 (IQR 1.72-2.28) mmol/L. Preoperative imaging was in the form of ultrasound of the neck in 21 of 48 (44%), MIBI scan in 27/48 (56%), contrast enhanced computerized tomography in 14/48 (29%) and MRI neck in 1/48 (2%). The mean size of the cancer was 2.7 (± 1.35) cm and weight of the gland ranged between 0.9 to 4.98 g. 18/48 (37%) patients underwent a total parathyroidectomy and 30/48 (63%) had subtotal parathyroidectomy. En bloc excision of the tumour along with the thyroid along and central compartment lymph nodes was only performed in 12/48 (25%), of whom 9 (19%) had it performed at index surgery, whereas in the rest was done for persistent or recurrent disease. After a mean follow up of 34 months, 14 (29%) had local recurrence, 1 (2%) had distant metastasis to the skeletal system, and 12 (25%) to the lungs. Cohort mortality was 6 (13%) due to refractory hypercalcemia.

Conclusions: Parathyroid carcinoma in renal hyperparathyroidism is rare but when encountered, en bloc excision with parathyroidectomy provides the best chance of cure. Recurrences can be difficult to treat but may be needed to treat intractable hypercalcaemia.