DIAGNOSTIC AND THERAPEUTIC ROLE OF THYROID REMNANT ABLATION WITH LOW ACTIVITY OF 131I IN PATIENTS WITH LOW AND INTERMEDIATE RISK PAPILLARY THYROID CARCINOMA (PTC).

摘要

The real need to perform thyroid residual ablation with 131I (RRA) is nowdays under debate, particularly in patients with low and intermediate risk PTC. \udObjective: In this study we evaluated the diagnostic and therapeutic role of this procedure.\udPatients: To this purpose we analyzed the data of 548 consecutive patients (pts) with PTC treated with total thyroidectomy, arrived at the Department of Endocrinology of Pisa in 2006 to perform RRA. All patients were treated in hypothyroidism with a standard activity of 30 mCi of 131I (1110 MBq) followed by a Whole Body Scan (pWBS). Neck ultrasound and serum thyroglobulin (Tg) and thyroid hormones measurements were performed in all pts. On the basis of TNM we classified patients in two groups: low risk (LR; n=348) and intermediate risk (IR; n=200).\udResults: In addition to the thyroid remnant, the pWBS showed the presence of further areas of 131I uptake in 16/548 (2.9%): 7 LR (2.2%) and 9 IR (4.3%) (p=0.09). The mean value of serum Tg was 86.329+112.398 ng/ml in LR and 242.411+260.779 ng/ml in IR (p=0.1). In 11/16 pts (4 LH, 7 IR) pWBS showed the presence of latero-cervical lymph node metastases, 9 out of 11 were also detected by neck ultrasound followed by fine needle aspiration citology (FNAC). The pWBS showed mediastinal uptake in 1/16 (1 IR), lung metastases in 3/16 (2 LR, 1 IR) and bone metastases in 1/16 (1 LR). Only 7/548 (1.3 %) (5 LR and 2 IR) metastases were detected by pWBS only. At the end of follow-up (median 7.8 years), 8/16 pts were free of disease (5 LR, 3 IR) while the other 8 had persistent disease: 5 “biochemical” disease (1 lung and 4 lymph nodes) and 3 “structural” disease (1 bone, 1 mediastinum and 1 lymph node). Remission was achieved in 3 cases after one single 131I activity, in 1 case after surgical treatment and in the last 4 cases after several 131I courses . \udConclusions: The pWBS after RRA played an important diagnostic role in only 1.3 % of PTC pts with no difference between LR and IR groups. Serum Tg was unable to predict pWBS positive cases. Three out of 3 cases with lung and 8/11 lymphnodes metastases revealed by pWBS have been cured by 131-I. Unfortunately, we do not know what could happen to these subjects, especially those with lung metastases, if the pWBS was not performed.