# Impact of concurrent parathyroid adenoma on the recurrence of differentiated thyroid carcinoma: a retrospective study

## TL;DR

This study investigates whether having a parathyroid adenoma affects the recurrence of thyroid cancer after surgery.

## Contribution

The study provides new insights into the relationship between parathyroid adenoma and thyroid cancer recurrence in a clinical setting.

## Key findings

- Patients with parathyroid adenoma had significantly different preoperative calcium, phosphorus, and PTH levels compared to those without.
- Residual thyroid tissue was less common in patients with parathyroid adenoma.
- Parathyroid adenoma does not directly impact thyroid cancer recurrence in the short term.

## Abstract

The impact of concurrent parathyroid adenoma in differentiated thyroid carcinoma remains unclear. This study compared the recurrence rates of patients operated on for differentiated thyroid carcinoma with concomitant parathyroid adenoma and those operated on for thyroid carcinoma without detected parathyroid adenoma.

This retrospective study examined 340 patients who underwent total thyroidectomy for thyroid carcinoma at our institution. We compared patients with concurrent parathyroid adenoma to those without, assessing clinical, laboratory, surgical, and histopathological findings and thyroid carcinoma recurrence over a 6-year postoperative period.

Among all patients, 53/340 (16%) were identified with parathyroid adenoma and were predominantly over the age of 50 years (p < 0.00). There was a significant difference between patients with and without parathyroid adenoma regarding the preoperative serum Ca level (11.21 ± 0.41 mg/dL versus 9.5 ± 0.36 mg/dL, respectively), preoperative serum P level (2.3 ± 0.3 mg/dL versus 3.7 ± 1.4 mg/dL, respectively), and preoperative serum PTH level (142 ± 89.3 pg/mL versus 53.7 ± 11.5 pg/mL, respectively) (p < 0.001 overall). Residual thyroid tissue was detected in 215/340 (63%) patients, and a significant difference existed between patients with parathyroid adenoma (20/53, 38%) and without it (195/287, 68%) (p < 0.00). No significant differences were observed in surgical and/or tumor characteristics between patients with and without parathyroid adenoma.

Our findings suggest that parathyroid adenoma has no direct impact on the recurrence of differentiated thyroid carcinomas in the short term. However, our small cohort size limits the generalizability of these results, indicating a need for further studies with larger patient populations and longer follow-up durations.