Usefulness of low iodine diet in managing patients with differentiated thyroid cancer - initial results

Abstract

BackgroundLow iodine diet (LID) is recommended in patients with differentiated thyroid cancer before radioiodine administration. Patients with increased thyroglobulin (Tg) level, but negative 131I whole body scan present diagnostic and therapeutic dilemma. This study was designed to evaluate the benefit of a two-week LID in patients with elevated serum Tg levels and negative 131I whole body scans.Patients and methods.For the impact assessment of two-week LID on radioiodine tissue avidity, radioiodine scans before and after LID were compared. Sixteen patients with serum Tg > 2 μg/L, negative Tg-antibodies, and negative radioiodine scans underwent two-week LID before the 131I administration. Fourteen patients underwent diagnostic scanning and two patients received radioiodine therapy. Iodine concentration in the morning urine specimens were measured in each patient, a day before and 15th day after starting LID.ResultsFollowing self-managed LID, patients were able to significantly reduce their iodine body content by 50% (range 28–65%, p<0,001). 13 patients (82%) accomplished mild iodine deficiency (50-99 μg/L) and one patient (6%) achieved targeted moderate iodine deficient state (<50 μg/L). All diagnostic post-LID scans were negative. Both post-therapy 131I scans showed radioiodine accumulation outside of normal 131I distribution (neck region and diffuse hepatic uptake). This study demonstrated that two-week LID is effective way to decrease total body iodine content, although without a visible effect on post-LID diagnostic 131I scans.ConclusionsA more stringent dietary protocol and longer iodine restriction period are probably needed to achieve targeted moderate iodine deficiency in patients preparing for 131I administration. This might result in higher radioiodine avidity of thyroid remnant/metastases.

Stimulated Serum Thyroglobulin Level at the Time of First Dose of Radioactive Iodine Therapy Is the Most Predictive Factor for Therapeutic Failure in Patients With Papillary Thyroid Carcinoma

“…Some studies revealed the association between a low iodine diet and ablation therapy. Choi et al showed that 24-h urine iodine excretion was significantly lowered after a stringent low iodine diet in Korean patients with thyroid cancer [28], and Dobrenic et al reported that a more stringent low iodine diet might result in higher radioiodine avidity in patients undergoing I-131 ablation therapy [29]. Maurice et al showed the percentage of patients with successful ablation was significantly high in the low iodine diet group compared with the normal diet group [30].…”

Effectiveness of L-thyroxine treatment on TSH suppression during pregnancy in patients with a history of thyroid carcinoma after total thyroidectomy and radioiodine ablation

“…There are very limited data in the literature about the changes of TSH and thyroid hormones during pregnancy in patients with a history of thyroid carcinoma. To our knowledge, these studies included only a small number of patients 8 , 12 – 15 with the largest study group of 18 such cases reported by Loh et al . 8 There are scarce data about the optimal increase of L-thyroxine dose during pregnancy in the patients with thyroid carcinoma after total thyroidectomy and radioiodine ablation of thyroid remnant.…”

Low Iodine Diet for Postoperative Patients with Thyroid Cancer in Vietnam

“…However, all of them suggested restriction of all kinds of seafood, milk and dairy products, instant food or commercial products (dressing, packaged rice…) [5,[14][15][16][17]. In this article, most of the guidelines on low iodine diet were updated by Korean researches from 2012 to 2016 [14,15] and the newest guideline from United Kingdom (2018) [18].…”