Incidental multifocal papillary microcarcinomas of the thyroid: is subtotal thyroidectomy combined with radioiodine ablation enough?

Background: The extent of thyroid resection and the necessity of lymph node dissection has become an issue of controversy in patients with incidental multifocal papillary microcarcinoma.
Method: Between 1993 and 2001 a total of 4120 patients underwent surgery for thyroid diseases: 142 patients showed papillary thyroid cancer of < or = 1 cm, multifocal microcarcinomas were found in 22 patients (15.5%). Twenty patients (17 women, three men, aged 26-71 years) met the inclusion criterion of having pre- and intraoperatively no indication of malignancy (incidentaloma). A limited surgical procedure ranging from bilateral subtotal (n=15), ipsilateral total, contralateral subtotal (n=4) to bilateral total (n=1) thyroidectomy without lymph node dissection was performed. The mean volume of thyroid remnants was 4.3 ml.
Results: In 16/20 (80%) patients, the thyroid remnant was ablated by the first dose of 131I, using 3.7 GBq 131I in 15 patients and 1.85 GBq 131I in one patient. Three patients received a second, and one patient a third radioiodine ablation. All 20 patients remained free from relapse or metastasis, documented by negative 131I whole-body scintigraphy and unmeasurable thyroglobulin levels after thyroid hormone withdrawal in hypothyroidism. One patient died 7 years after the diagnosis of thyroid cancer from primary lung cancer. Median follow-up was 65 months (range, 24-120 months).
Conclusion: Subtotal thyroidectomy followed by radioiodine therapy without completion thyroidectomy and lymphadenectomy is a possible option in incidental multifocal microcarcinomas.