Implications of mediastinal uptake of ¹³¹I with regard to surgery in patients with differentiated thyroid carcinoma

Abstract

BACKGROUNDFindings of mediastinal uptake of 131I after surgical treatment for differentiated thyroid carcinoma (DTC) are common, especially in young patients. Given the frequency of false‐positive findings, a protocol for diagnostic and therapeutic strategies would be useful. With the goal of accurately selecting management strategies, the authors analyzed their data and data found elsewhere in the literature for correlations with the incidence of mediastinal 131I uptake and with treatment for patients exhibiting such 131I uptake.METHODSAll patients with DTC who were treated between 1978 and 2000 at Groningen University Hospital (Groningen, The Netherlands) and who received adjuvant 131I ablation therapy were included in the current analysis, which involved retrospective review of all relevant data.RESULTSFive hundred four patients with DTC initially underwent total thyroidectomy, with additional 131I ablation performed for 489 of these patients. In 48 of 489 patients (9.8%), 131I uptake was seen in the mediastinum on a posttreatment scan. Analysis of those 48 patients and of cases in the literature demonstrated that serum thyroglobulin levels, risk status, and the presence of thymus on radiologic images were important in the surgical decision‐making process.CONCLUSIONSMediastinal uptake of 131I on posttreatment scans was found in approximately 10% of patients after total thyroidectomy for DTC. Based on the current data and the data presented in the literature, the authors developed a flow chart for determining appropriate treatment strategies, which included mediastinal dissection for high‐risk patients and for patients with serum thyroglobulin levels > 10 ng/mL. Cancer 2005. © 2004 American Cancer Society.

The follow-up of patients with differentiated thyroid cancer and undetectable thyroglobulin (Tg) and Tg antibodies during ablation

“…Low-risk patients were defined as patients younger than 40 years with a T0-T3 papillary thyroid carcinoma without distant metastases or patients with intrathyroidal follicular carcinoma or Hü rthle cell carcinoma without nodal and distant metastases. High-risk patients were defined as patients of 40 years and older, with extrathyroidal cancer (T4), or nodal metastases (N1) in the case of follicular carcinoma or Hü rthle cell carcinoma and patients with distant metastases (M1) (15).…”

Thymic uptake after high-dose I-131 treatment in patients with differentiated thyroid carcinoma: A brief review of possible causes and management

“…2,3 The incidence of thymus visualization on 131-I scintigraphy has been reported between 3.4% and 26.3% in four series, the largest with 489 patients by Haveman et al 4 It seems that there is a link in the embryological development between the thymus and thyroid gland; during the sixth week of gestation, the thymus arises from the third and fourth pharyngeal pouch, in the seventh week it elongates and acquires a cylindrical shape and migrates caudally to the superior mediastinum. 2,3 The incidence of thymus visualization on 131-I scintigraphy has been reported between 3.4% and 26.3% in four series, the largest with 489 patients by Haveman et al 4 It seems that there is a link in the embryological development between the thymus and thyroid gland; during the sixth week of gestation, the thymus arises from the third and fourth pharyngeal pouch, in the seventh week it elongates and acquires a cylindrical shape and migrates caudally to the superior mediastinum.…”

Thymic uptake after high-dose I-131 treatment in patients with differentiated thyroid carcinoma: A brief review of possible causes and management

“…2,3 The incidence of thymus visualization on 131-I scintigraphy has been reported between 3.4% and 26.3% in four series, the largest with 489 patients by Haveman et al 4 It seems that there is a link in the embryological development between the thymus and thyroid gland; during the sixth week of gestation, the thymus arises from the third and fourth pharyngeal pouch, in the seventh week it elongates and acquires a cylindrical shape and migrates caudally to the superior mediastinum. The thyroid gland is derived from the pharyngeal epithelium, but there are suggestions of some authors that there is a contribution from the fourth pharyngeal pouch.…”