Toxic nodular goiter and cancer: a compelling case for thyroidectomy

Recent American Thyroid Association guidelines call for thyroidectomy or (131)I (Recommendation 31) in managing hyperthyroidism due to toxic nodular goiter (TNG). Concern for concomitant malignancy favors surgery. A 3 % thyroid cancer incidence in TNG patients has been reported, yet recent studies suggest this rate is underestimated. This multi-institutional study examined cancer incidence in TNG patients referred to surgery.

Patients referred for thyroidectomy at three tertiary-care institutions were included (2002-2011). Patients with concurrent indeterminate or malignant diagnosis by fine-needle aspiration (FNA) were excluded. Cancer incidence in TNG patients was determined. Fisher's exact and chi-square tests and nonparametric t tests were used.

Among 2,551 surgically treated patients, 164 had TNG (6.4 %). Median age at presentation was 49.7 years, and 86 % were female. Overall cancer incidence was 18.3 % (30 of 164), and rates were not significantly different between institutions. A significantly greater cancer rate was noted in toxic multinodular goiter versus single toxic nodule patients (21 vs. 4.5 %, P < 0.05). Mean tumor size was 0.71 cm (range 0.1-1.5 cm; 23 % ≥1 cm). Most patients underwent total or near-total thyroidectomy. There were no significant differences in tumor sizes among institutions (P > 0.05). No significant cancer association was noted with age, preoperative dominant nodule size, lymphocytic thyroiditis or preoperative FNA (P > 0.05).

These data demonstrate a higher than expected incidental cancer rate in TNG patients compared to historical reports (18.3 vs. 3 %). This higher cancer incidence may alter the risk/benefit analysis regarding TNG treatment. This information should be provided to TNG patients before decision making regarding treatment.