Prevalence of adverse pathological features in 1 to 4 cm low-risk differentiated thyroid carcinoma.

Background: The American Thyroid Association (ATA) recommends thyroid lobectomy for 1 to 4 cm tumors without adverse features. We studied the prevalence of adverse pathological features in patients eligible for unilateral lobectomy.

Methods: We conducted a retrospective study of patients who underwent total thyroidectomy. Patients with differentiated thyroid cancer (DTC) with tumors measuring 1 to 4 cm with no known preoperative adverse features were included in this study. Patients with nodal and distant metastasis, tumors <1 cm to > 4 cm, age < 17 years old, and gross extrathyroidal extension were excluded. Patients with bilateral nodularity on imaging were excluded from the final analysis on adverse features.

Results: There were 59.1% of patients undergoing thyroidectomy with tumors measuring 1 to 4 cm and no preoperatively known adverse features who were eligible for lobectomy under current ATA guidelines who would have needed a completion thyroidectomy after pathological analysis of the index tumor.

Conclusion: Two thirds of the patients may require a completion thyroidectomy if unilateral lobectomy is done in tumors measuring 1 to 4 cm based on adverse pathological features.