Radiotherapy in well-differentiated thyroid cancer: is it underutilized?

Recurrent Differentiated Thyroid Cancer: The Current Treatment Options

Differentiated thyroid carcinomas (DTC) have an excellent prognosis, but this is sometimes overshadowed by tumor recurrences following initial treatment (approximately 15% of cases during follow-up), due to unrecognized disease extent at initial diagnosis or a more aggressive tumor biology, which are the usual risk factors. The possible sites of recurrence are local, regional, or distant. Local and regional recurrences can usually be successfully managed with surgery and radioiodine therapy, as are some isolated distant recurrences, such as bone metastases. If these treatments are not possible, other therapeutic options such as external beam radiation therapy or systemic treatments should be considered. Major advances in systemic treatments have led to improved progression-free survival in patients previously considered for palliative treatments; among these treatments, the most promising results have been achieved with tyrosine kinase inhibitors (TKI). This review attempts to give a comprehensive overview of the current treatment options suited for recurrences and the new treatments that are available in cases where salvage surgery is not possible or in cases resistant to radioiodine.

Nutrition in Advanced Thyroid Cancer Patients

In the last decade, multikinase inhibitors (MKIs) have changed the paradigm of treatment of advanced and progressive thyroid cancer. Compared with the traditional treatment with chemotherapy and radiotherapy, these new drugs have shown a good efficacy in controlling the neoplastic disease, and also a different toxicity profile compared to traditional chemotherapy, milder but still present and involving mainly the nutritional profile. Weight loss, nausea, anorexia, stomatitis, diarrhea may be associated with malnutrition and cancer-related cachexia. The latter is characteristic of the advanced cancer stage and may be present before starting MKIs, or may develop afterwards. Adverse events with nutritional impact may cause a significant impairment of quality of life, often requiring dose reduction and sometimes drug discontinuation, but with a lower efficacy on the neoplastic disease. The aim of this paper was to discuss the role of nutritional therapy in advanced thyroid cancer and the importance of prevention, early recognition and careful management of malnutrition and cachexia during systemic therapy with MKIs.

Radioiodine Refractory Follicular Thyroid Cancer and Surgery for Cervical Relapse

Compared to its more common counterpart papillary thyroid cancer (PTC), follicular thyroid cancer (FTC) has a less favorable outcome, due to its higher incidence of distant metastases and advanced stages at diagnosis. Despite radioiodine (RAI) avidity, metastatic FTC often progresses after radioiodine treatment (RAIT). We aimed at evaluating the indications and outcomes of surgery for cervical relapse of radioiodine refractory FTC. Patients receiving RAIT between 2005 and 2015 at the University Hospital of Cologne, Germany, were screened. Patients with FTC were identified. Demographics, clinic-pathologic characteristics, treatment, and outcome of patients diagnosed with RAI refractory FTC, who underwent cervical surgery in the course of disease, were analyzed. FTC accounted for 8.8% of all thyroid carcinomas undergoing RAIT. In 35.2% of FTC patients, disease persisted or recurred despite a cumulative mean RAI activity of 18.7 GBq ± 11.6 (follow-up 83.5 ± 56.7 months). Distant metastases were diagnosed in 75% of these patients, as bone (57.6%), lung (54.6%), and liver metastases (12.1%). Cervical relapse occurred in 63.6% of these patients and was treated in 57.1% with surgery with, and without, external beam radiation therapy (EBRT). Despite surgery and EBRT, in 75% of patients, cervical relapse recurred again. In conclusion, surgery for cervical radioiodine refractory FTC relapse is often performed in metastatic setting. With and without EBRT, cure is rare, although metastases can appear radioiodine avid. Early biological marker and systemic treatments for these patients are still needed.

[Efficacy and tolerance of salvage curative radiotherapy for patients with cervical relapse of differentiated thyroid carcinoma]

PURPOSE

Radiation therapy is often the last resource treatment for cervical relapse in iodine refractory differentiated thyroid cancer. We present locoregional control data in patients with cervical relapse treated with curative intent radiation therapy with or without concomitant carboplatin.

MATERIAL AND METHODS

This monocentric retrospective study gathered data on patients with differentiated thyroid carcinoma - vesicular or papillary - in relapse after thyroidectomy who received a curative intent cervical radiation therapy. Locoregional progression free survival (LRPFS), progression free survival (PFS), overall survival (OS) were gathered as well as acute and chronic adverse events assessed with the CTCAE v4.

RESULTS

Thirty-nine patients were consecutively included between 2005 and 2019. The median follow-up was 36.6months. Fifteen patients (38%) had a locoregional relapse, locoregional control at 2years was 66.7%. The median LRPFS was 48months [32.9-not reached] and the median overall survival 49months [38.8-not reached]. In multivariate analysis, initial incomplete resection was associated with poorer OS (HR: 24.39 [3.57-166.78], P=0.00113) and LRPFS (HR: 33.91 [4.46-257.61], P=0.00066), extra nodal spread was associated with poorer LRPFS (HR: 13.45 [1.81-99,76], P=0.011). ECOG performance status was associated with OS (HR: 5.11 [1.57-16.66], P=0.00688). Carboplatin association with radiation therapy was not associated with improved survivals (OS: P=0.34, LRPFS: P=0.84). The rate of acute grade 3 toxicities was 14%.

CONCLUSION

Salvage cervical radiation therapy was associated with a locoregional control of 66.7% at 2years with a reasonable toxicity rate. Carboplatin association with radiation therapy did not improve locoregional control nor overall survival in comparison with radiotherapy alone.

Treatment of Unresectable Differentiated Thyroid Carcinoma With Upfront External Radiotherapy and Salvage Surgery: A STROBE-Compliant Retrospective Cohort Study

INTRODUCTION

In patients with unresectable Differentiated thyroid cancer (DTC), the use of external beam radiation therapy (EBRT), leads mostly to palliation. Our aim is to define the role of upfront EBRT, followed or not by salvage surgery, on Progression-free survival (PFS) or Overall survival (OS) in patients with DTC.

METHODS

This is a cohort study of patients with initially unresectable DTC who received EBRT. Cohort A received EBRT followed by rescue surgery and cohort B, EBRT only. The Kaplan-Meier method and Cox model were employed for survival analysis.

RESULTS

Thirty-three patients were included; 69.6% females and 30.3% males. Mean age was 60.6 and mean tumor diameter was 10.4 cm; 17 and 16 patients were included in cohorts A and B, respectively. Belonging to cohort A (Hazard ratio [HR] 0.177, 95% CI 0.05-0.7) and use of intensity modulated radiotherapy (HR 0.177, 95% CI 0.03-1.08) were associated to better PFS, while high-risk histopathology (HR 6.6, 95% CI 0.9-50) and EBRT dose (HR 1.05, 95% CI 1.01-1.08) were independently associated with lower PFS. Patients from cohort A (HR 0.061, 95% CI 0.01-0.3) had improved OS, while high-risk histopathology (HR 5.7, 95% CI 1.1-28.6) and EBRT dose (HR 1.05, 95% CI 1.01-1.09) were independently associated to worse OS.

CONCLUSION

EBRT, and when feasible, salvage surgery, should be an integral part of the therapeutic strategy in initially unresectable DTC.

2019 European Thyroid Association Guidelines for the Treatment and Follow-Up of Advanced Radioiodine-Refractory Thyroid Cancer

The vast majority of thyroid cancers of follicular origin (TC) have a very favourable outcome, but 5-10% of cases will develop metastatic disease. Around 60-70% of this subset, hence less than 5% of all patients with TC, will become radioiodine refractory (RAI-R), with a significant negative impact on prognosis and a mean life expectancy of 3-5 years. Since no European expert consensus or guidance for this challenging condition is currently available, a task force of TC experts was nominated by the European Thyroid Association (ETA) to prepare this document based on the principles of clinical evidence. The task force started to work in September 2018 and after several revision rounds, prepared a list of recommendations to support the treatment and follow-up of patients with advanced TC. Criteria for advanced RAI-R TC were proposed, and the most appropriate diagnostic tools and the local, systemic and palliative treatments are described. Systemic therapy with multikinase inhibitors is fully discussed, including recommendations on how to start it and at which dosage, on the duration of treatment, and on the management of side effects. The appropriate relationship between the specialist and the patient/family as well as ethical issues are covered. Based on the available studies and on personal experience, the experts provided 39 recommendations aimed to improve the management of advanced RAI-R TCs. Above all of them is the indication to treat and follow these patients in a specialized setting which allows the interaction between several specialists in a multidisciplinary team.