Recurrence after treatment for differentiated thyroid cancer: Observations on risk factors, long-term follow-up and treatments

The prognosis of differentiated thyroid cancer (DTC) is good, and radical surgery has been questioned, especially for small tumors. Size alone cannot, however, predict prognosis. Recurrences occur after several decades, and other risk factors should be included when deciding on an optimal treatment strategy.

A consecutive series of 231 patients with DTC were treated in 2004-2016 at Borås Hospital in Sweden. Follow-up was performed in 2023, after a mean of 10.7 years (range = 6.5-19.1). Data on type of surgery, adjuvant radioiodine treatment, thyroglobulin levels, deaths, and recurrences were collected. Patients with negative thyroglobulin levels after treatment were compared with those who had measurable thyroglobulin or high levels of anti-thyroglobulin.

In 63/231 patients (27.3%), there was no preoperative suspicion of malignancy, 214 (92.6%) patients underwent total thyroidectomy, and the complication rate was low. There were 181 patients (84.6%) with negative thyroglobulin after treatment, and 33 patients (14.3%) with measurable thyroglobulin and/or anti-thyroglobulin levels. Fifteen patients died from thyroid cancer, and all were in the latter group. Risk factors for recurrence were tumor size, vascular invasion, extra-thyroidal growth, lymph node metastases, and male sex. Multifocality was frequent (32.5%) and patients with bi/multifocal cancers had significantly more lymph node metastases. Ten patients with recurrences had at least two of the identified risk factors.

Total thyroidectomy or hemithyroidectomy in DTC is recommended, preferably including the central lymph node clearance. Total thyroidectomy has the advantage of allowing follow-up with thyroglobulin measurements to detect recurrences in time for treatment.