Does previous head and neck irradiation increase the chance of multigland disease in patients with hyperparathyroidism?

BACKGROUND

Exposure to therapeutic radiation, whether used to treat lymphoma, breast cancer, or benign conditions, such as acne, is thought to cause an increased risk for thyroid and/or parathyroid neoplasia. We therefore investigated whether patients with a history of head/neck irradiation and hyperparathyroidism (HPT) had a higher incidence of multigland disease.

METHODS

Between November 2000 and May 2010, 1,428 patients with HPT underwent parathyroidectomy at our institution. Of these cases, 39 patients (2.7%) had a history of radiation exposure (RADRX). These 39 cases were compared with the 1,389 cases without prior exposure (NO RAD RX).

RESULTS

There were no significant differences in gender or age between the two groups. Whereas most laboratory values were similar, preoperative parathyroid hormone levels were higher in the NO RADRX patients (174 ± 7 vs. 106 ± 8 pg/ml; P < 0.001). Interestingly, the resected parathyroid glands were significantly smaller in the RADRX group compared with the NO RADRX group (511 ± 70 vs. 790 ± 37 mg; P = 0.001). No differences were noted in the recurrence rate (P = 0.392). Contrary to common belief, RADRX patients did not have a significantly higher incidence of multigland disease (P = 0.774). Of the 39 RADRX patients, 12 (31%) had multigland disease, whereas 398 of the 1,389 (28%) NO RADRX patients had multigland disease.

CONCLUSIONS

Surgical outcomes are excellent in patients with a previous history of radiation and HPT who undergo parathyroidectomy. Previous radiation exposure does not appear to increase the likelihood of multigland disease in patients with HPT.