Balancing the benefits and harms of thyroid cancer surveillance in survivors of Childhood, adolescent and young adult cancer: Recommendations from the international Late Effects of Childhood Cancer Guideline Harmonization Group in collaboration with the PanCareSurFup Consortium

Highlights

• We developed recommendations for DTC surveillance in CAYAC survivors.

• At-risk survivors should be counseled about options for DTC surveillance.

• It is recommended to use palpation or ultrasonography as a screening modality.

• Consultation with a thyroid specialist is recommended for survivors with a thyroid nodule.

Abstract

Radiation exposure to the thyroid gland during treatment of childhood, adolescent and young adult cancer (CAYAC) may cause differentiated thyroid cancer (DTC). Surveillance recommendations for DTC vary considerably, causing uncertainty about optimum screening practices. The International Late Effects of Childhood Cancer Guideline Harmonization Group, in collaboration with the PanCareSurFup Consortium, developed consensus recommendations for thyroid cancer surveillance in CAYAC survivors. These recommendations were developed by an international multidisciplinary panel that included 33 experts in relevant medical specialties who used a consistent and transparent process. Recommendations were graded according to the strength of underlying evidence and potential benefit gained by early detection and appropriate management. Of the two available surveillance strategies, thyroid ultrasound and neck palpation, neither was shown to be superior. Consequently, a decision aid was formulated to guide the health care provider in counseling the survivor. The recommendations highlight the need for shared decision making regarding whether to undergo surveillance for DTC and in the choice of surveillance modality.

Introduction

Childhood, adolescent and young adult (CAYAC) survivors are at risk for developing subsequent malignancies [1], [2], [3], [4], [5], [6], [7], of which approximately 10% involve the thyroid gland [7]. The occurrence of differentiated thyroid carcinoma (DTC) is predominantly attributable to radiation therapy that directly or incidentally involves the thyroid gland [8], [9], [10]. Among CAYAC survivors who received radiation exposure to the thyroid gland, standard incidence ratios of DTC range from 5- to 69-fold depending on radiation dose [8]. Consequently, periodic surveillance of CAYAC survivors at increased risk of developing DTC has been advocated [11], [12], [13]. However, since most DTC have a favourable prognosis [14], there is debate regarding both the necessity of routine surveillance and the optimal modality for screening. Surveillance for late effects can expose survivors to unnecessary harms if it results in overdiagnosis or false positive test results, both of which can result in avoidable distress. For this reason, some deem that recommending health screening is unethical unless all possible harms as documented by the best available evidence are considered in the context of potential benefits [15]. To guide the clinical care of CAYAC survivors at increased risk for DTC, the International Late Effects of Childhood Cancer Guideline Harmonization Group (IGHG) appointed an expert panel to examine and summarize all available evidence regarding the risk factors for DTC and the benefits, risks, and harms of different strategies for screening for occult DTC. Herein, we present recommendations for surveillance of CAYAC survivors at risk for DTC that were formulated following evaluation of this evidence.