Individualized treatment of differentiated thyroid cancer: The value of surgery in combination with radioiodine imaging and therapy – A German position paper from Surgery and Nuclear Medicine

Abstract

A consensus statement about indications for post-surgical radioiodine therapy (RIT) in differentiated thyroid cancer patients (DTC) was recently published by the European Thyroid Association (ETA) 1. This publication discusses indications for RIT on the basis of an individual risk assessment. Many of the conclusions of this consensus statement are well founded and accepted across the disciplines involved. However, especially from the perspective of nuclear medicine, as the discipline responsible for indicating and executing RIT, some of the recommendations may require further clarification with regard to their compatibility with established best practice and national standards of care. Assessment of the indications for RIT is strongly dependent on the weighing up of benefits and risks. On the basis of longstanding clinical experience in nuclear medicine, RIT represents a highly specific precision medicine procedure of proven efficacy with a favorable side-effect profile. This distinguishes RIT significantly from other adjuvant oncological therapies and has resulted in the establishment of this procedure as a usually well-tolerated, standard safety measure. With regard to its favorable risk/benefit ratio, this procedure should not be unnecessarily restricted, in the interest of offering reassurance to the patients. Both patients’ interests and regional/national differences need to be taken into account. We would therefore like to comment on the recent consensus from the perspective of authors and to provide recommendations based on the respective published data.

Application of the American Thyroid Association Risk Assessment in Patients with Differentiated Thyroid Carcinoma in a German Population

“…The fact that even patients with a low risk can show persistent disease, even if they are few, should be kept in mind. This is an important aspect to consider in everyday clinical practice and should be carefully taken into account, especially with regard to the currently discussed indication for radioiodine therapy [ 15 , 16 ]. A recent German position paper by nuclear medicine physicians and endocrine surgeons, written by Schmidt et al, summarizes areas of disagreement based on a literature review in comparison with the ATA [ 15 ].…”

“…This is an important aspect to consider in everyday clinical practice and should be carefully taken into account, especially with regard to the currently discussed indication for radioiodine therapy [ 15 , 16 ]. A recent German position paper by nuclear medicine physicians and endocrine surgeons, written by Schmidt et al, summarizes areas of disagreement based on a literature review in comparison with the ATA [ 15 ]. The ATA and the ETA are cautious about RAI in low-risk patients and see the indication for it only in individual exceptional cases.…”

“…Accounting for the well-known high incidence of lymph node metastases, adjuvant therapy, as opposed to remnant ablation, is therefore traditionally pursued in Germany. This is why patients usually receive activities that are considered to be therapeutically appropriate [ 15 , 16 , 18 ]. Tuttle et al emphasize in their joint statement by the ATA, EANM, SNMMI and ETA that a clear distinction should be made between a remnant ablation and an adjuvant therapy concept, specifically that the latter is heavily influenced by local conditions [ 19 ].…”

Initial results of the INSPIRE clinical trial—investigating radiation dosimetry for differentiated thyroid cancer patients

“…The decision to treat with RAI following thyroidectomy and the level of activity to administer should be based on the riskbenefit ratio. The benefit of RAI therapy, especially for low-risk differentiated thyroid cancer (DTC) patients, remains controversial (3)(4)(5). Leboulleux et al showed in a prospective, randomised, phase 3 trial (ESTIMABL2) of patients with low-risk DTC [T1(m) N0 M0] that surveillance is non-inferior to RAI therapy for event-free survival at 3 years (6).…”

SNMMI/EANM practice guideline vs. ETA Consensus Statement: differences and similarities in approaching differentiated thyroid cancer management—the EANM perspective

“…[2]. In addition, not long ago, a German position paper from surgery and nuclear medicine was published in reaction to the ETA Consensus Statement with a very different perspective, similar to the newly published SNMMI/EANM guideline [3]. Overall, despite the use of the widely accepted riskadapted therapy, its interpretation and relative approaches to DTC management, and in particular to the clinical use of radioactive iodine, still differ significantly in European countries [4].…”