ESPE Yearbook of Paediatric Endocrinology

Eur J Endocrinol. 2020; 183: 169–180. https://pubmed.ncbi.nlm.nih.gov/32449692/

This retrospective study analyzed subsequent differentiated thyroid cancer (DTC) in in a group of CCS (n=31) matched with patients affected by sporadic DTC (n=93) to compare clinical presentation and outcomes. CCS with subsequent DTC were identified by two source populations: the DCOG-LATER cohort of more than 6000 5-year CCS diagnosed with a primary tumor between 1963 and 2001, and The Netherlands Cancer Registry, for cases diagnosed after 2001. Unsurprisingly, CCS with subsequent DTC presented with smaller and more frequently bilateral tumors. DTC can probably be detected when they are smaller in CCS, because these patients receive careful long-term follow-up. On the other hand, DTC are more often bilateral in CCS because thyroid irradiation results in a diffuse toxicity.

Childhood cancer survivors (CCS), are at risk of subsequent malignancies, approximately 10% of these involve the thyroid gland. The occurrence of a differentiated thyroid cancer in CCS is predominantly related to radiotherapy; the risk increases linearly with estimated radiation dose to the thyroid gland, with a plateau at ~10–30 Gy and a decline at higher doses (1).

Two aspects of this study are noteworthy. First, one-third of CCS with subsequent DTC had been treated with chemotherapy only, which prompts reflection on the intrinsic risk due to chemotherapy. Second, subsequent DTC were detected by routine neck palpation (46.2%), self-identified mass (34.6%), or by chance (19.2%). Notably, none was diagnosed by ultrasound screening, the use of which is still debated (2-4). Admittedly, this retrospective study presents a dated cohort (1963-2015). Evidence in recent years consider ultrasound superior to palpation for thyroid cancer detection in high-risk CCS (5).

Reference: 1. Lubin JH, et al. Thyroid Cancer Following Childhood Low-Dose Radiation Exposure: A Pooled Analysis of Nine Cohorts. J Clin Endocrinol Metab. 2017 Jul 1; 102: 2575–83.2. Children’s Oncology Group (2018) Long-term follow-up guidelines for survivors of childhood, adolescent, and young adult cancer, version 5.0. www.survivorshipguidelines.org. Accessed October 20183. Gharib H, et al. (2016)American Association of Clinical Endocrinologists, American College of Endocrinology, and Associazione Medici Endocrinologi medical guidelines for clinical practice for the diagnosis and management of thyroid nodules – 2016 update. Endocr Pract 22 (Supplement 1): 1–60.4. Clement SC, et al. (2018) 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. Cancer Treat Rev 63:28–395. Hess J, et al. Ultrasound is superior to palpation for thyroid cancer detection in high-risk childhood cancer and BMT survivors. Support Care Cancer. 2020 Feb 11. doi: 10.1007/s00520-020-05340-0.