Follow-up of low-risk patients with differentiated thyroid carcinoma: a European perspective

Abstract

Objective: Because differentiated (follicular and papillary) thyroid cancer (DTC) may recur years after initial treatment, the follow-up of patients with DTC is long term. However, this population has changed, with more individuals being discovered at an earlier stage of the disease, so that previous follow-up protocols based mostly on data from high-risk patients no longer apply. We sought to develop an improved protocol for the follow-up of low-risk patients with DTC based on the findings of recent studies. Methods: We analysed recent literature on the follow-up of DTC. Results: Recent large studies have produced three important findings: (i) in patients with low-risk DTC with no evidence of disease up to the 6-to 12-month follow-up, diagnostic whole-body scan adds no information when serum thyroglobulin (Tg) is undetectable and interference from anti-Tg antibodies is absent; (ii) use of recombinant human thyroid-stimulating hormone to aid Tg measurement is effective and provides greater safety, quality-of-life and work productivity than does levothyroxine withdrawal with its attendant hypothyroidism; and (iii) ultrasonography performed by an experienced operator is the most sensitive means of detecting neck recurrences of DTC. Conclusions: We present a revised follow-up protocol for low-risk patients taking into account the above findings. This protocol should help clinicians enter a new era of monitoring characterized by greater safety, simplicity, convenience and cost savings.

Management Guidelines for Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Taskforce

“…For assessment of risk of recurrence, a three level stratification can be used. Low-risk patients have the following characteristics after initial surgery and remnant ablation: no local or distant metastases; all macroscopic tumor has been resected, there is no tumor invasion of locoregional tissues or structures, the tumor does not have aggressive histology (e.g., tall cell, insular, columnar cell carcinoma) or vascular invasion, and, if 131 I is given, there is no 131 I uptake outside the thyroid bed on the first posttreatment wholebody radioiodine scan (RxWBS) (177)(178)(179). Intermediate-risk patients have microscopic invasion of tumor into the perithyroidal soft tissues at initial surgery or tumor with aggressive histology or vascular invasion (180)(181)(182).…”

“…Serum thyroglobulin has a high degree of sensitivity and specificity to detect thyroid cancer, especially after total thyroidectomy and remnant ablation, with the highest degrees of sensitivity noted after thyroid hormone withdrawal or stimulation using recombinant human thyrotropin (rhTSH) (185). Serum thyroglobulin measurements obtained during thyroid hormone suppression of TSH may fail to identify patients with relatively small amounts of residual tumor (177,186). Conversely, even TSH-stimulated thyroglobulin measurement may fail to identify patients with clinically significant tumor, because of antithyroglobulin antibodies, or less commonly, defective or absent production and secretion of immunoreactive thyroglobulin by tumor cells (187).…”

“…Initial follow-up for low-risk patients (approximately 85% of postoperative patients) who have undergone total or neartotal thyroidectomy and 131 I remnant ablation should be based mainly on TSH-suppressed thyroglobulin and cervical ultrasound, followed by TSH-stimulated serum thyroglobulin measurements if the TSH-suppressed thyroglobulin testing is undetectable (177,186).…”

“…Disease not visualized on the DxWBS, regardless of the activity of 131 I used, may occasionally be visualized on the RxWBS images done after larger, therapeutic amounts of 131 I (186,(203)(204)(205)(206). After radioiodine ablation, subsequent DxWBS have low sensitivity and are usually not necessary in low-risk patients who are clinically free of residual tumor and have an undetectable serum thyroglobulin level during thyroid hormone suppression of serum TSH and negative cervical ultrasound (177,183,186,205,207). R46.…”

Why radioiodine remnant ablation is right for most patients with differentiated thyroid carcinoma

“…They also highlight the problem in comparing such studies in terms of outcome: in the various studies different 'staging' systems were used, in which the lowest risk stages varied widely. Therefore recent internationally acclaimed guidelines and consensus statements [3,4,21,22] at least clearly categorize patients who should not, who might, and who should receive RRA treatment according to the (pathological) extension of the disease. In a further development of staging, even RRA treatment itself may facilitate staging and further follow-up of DTC.…”