Cancer after thyroidectomy: a multi-institutional experience with 1,523 patients

Area of Science:

• Endocrinology
• Surgical Oncology
• Pathology

Background:

• Historically, incidental thyroid cancer rates (<5%) were low in patients undergoing surgery for thyroid disease.
• Previous studies have not specifically compared cancer rates in euthyroid versus hyperthyroid patients.
• This research investigated cancer frequency in patients referred for benign thyroid disease removal across multiple institutions.

Purpose of the Study:

• To determine the frequency of incidental thyroid cancer in patients undergoing thyroidectomy for benign thyroid conditions.
• To compare cancer rates among patients with Graves' disease, nodular goiter, and toxic nodular goiter.
• To identify patient and disease factors associated with incidental thyroid carcinoma.

Main Methods:

• A multi-institutional analysis of 2,551 patients who underwent thyroidectomy, excluding those with pre-existing indeterminate/malignant fine-needle aspiration results (n=1,028).
• Comparison of cancer cases among 1,523 patients with Graves' disease (n=264), nodular goiter (n=1,095), and toxic nodular goiter (n=164).
• Statistical analyses included Fisher's exact test, chi-square, Wilcoxon rank sum, Kruskal-Wallis tests, and multivariable logistic regression.

Main Results:

• An overall incidental thyroid cancer rate of 15.6% (238 cases) was observed.
• Cancer rates varied significantly by condition: Graves' disease (6.1%), nodular goiter (17.5%), and toxic nodular goiter (18.3%).
• Nodular thyroids, male sex, and younger age were significantly associated with increased cancer risk; thyroiditis and preoperative fine-needle aspiration were not.

Conclusions:

• This large multi-institutional series confirms a higher-than-expected incidental thyroid cancer rate of 15.6%.
• Nodular thyroid disease, male gender, and younger patient age are risk factors for incidental thyroid carcinoma.
• The findings support considering total thyroidectomy as the primary surgical approach for patients with bilateral nodular thyroid disease.