Relapse of differentiated thyroid carcinoma in low-risk patients

INTRODUCTION: The low incidence of relapse in differentiated thyroid carcinoma (DTC), primarily treated by total thyroidectomy and (131)I ablation, stimulates the search for optimal follow-up algorithms which do not include too many tests but are not connected with a risk of missing early recurrence. The aim of the study was to analyze the impact of the routine follow up examinations for early detection of DTC recurrence in low risk DTC patients. MATERIAL AND METHODS: The group consisted of 617 DTC patients diagnosed in 1995-1996. In 513 (83%) total thyroidectomy was performed. 449 (73%) received ablative (131)I therapy. After primary approach complete remission (CR) was stated in 453 (73%), persistent disease in 116 (19%), asymptomatic hyperthyroglobulinaemia in 14 (2%). Patients with CR constituted the low risk group analyzed in this study. The median follow up was 4.16 yrs. RESULTS: Recurrent disease appeared in 28 (6%) patients (23 locoregional, 9 distant metastases, both in 4). Serum Tg (thyroglobulin) level at the moment of relapse diagnosis was detectable in 44% while neck sonography was the first examination to detect recurrence in 56% of cases. CONCLUSION: In the selected group of DTC patients treated by radical primary approach and showing a low risk of recurrence only half of all relapse cases are diagnosed by the rise of serum Tg level. Regular sonography contributes to the second half of diagnoses. Thus, a special weight should be put on neck sonography as the important element of regular follow up in low risk DTC patients.