Background: The optimal extent of surgery for unilateral papillary thyroid carcinoma (PTC) with contralateral nodules remains unclear. This study evaluated the long-term outcomes in a large cohort of patients with unilateral PTC and contralateral low-to-intermediate suspicious nodules who underwent lobectomy. Methods: This retrospective cohort study included patients with unilateral PTC who underwent lobectomy between January 2016 and December 2017 at Asan Medical Center in Korea. Patients were divided into two groups, those with and without contralateral nodules at the time of lobectomy: the Present group and the Absent group. All contralateral nodules observed at the time of surgery and during follow-up were evaluated. Results: The study cohort consisted of 1761 patients (1879 nodules), including 700 (39.8%) with and 1061 (60.2%) without contralateral nodules. The median size of the contralateral nodules was 0.5 cm. After a median follow-up of 59 months, the median growth of the contralateral nodules in the Present group was 0.1 cm (range, -3.4 to 4.7 cm). Of the contralateral nodules present at the time of lobectomy, 54.7% remained unchanged, decreased in size, or disappeared; whereas 14.8% increased ≥0.3 cm. Of the 700 patients with contralateral nodules, 20 (2.9%) were diagnosed with contralateral PTC. The 5-year contralateral PTC disease-free survival rates in patients with and without contralateral nodules were 98.2% and 99.3% (p = 0.003), respectively, whereas the 5-year recurrence-free survival rates did not differ significantly in these two groups. Of the 39 patients who underwent completion thyroidectomy, 2 (5.1%) experienced permanent hypocalcemia. Conclusions: Lobectomy may be a safe and feasible initial treatment option for patients with unilateral low-risk PTC and contralateral low-to-intermediate suspicious nodules.
Keywords: papillary thyroid cancer; recurrence; thyroid nodule; thyroidectomy.