Secondary Thyroid Cancer Risks from External Beam Radiation Exposure Modulated by Dose, Field, Sex, Age, and Latency Period

Abstract

Introduction: Exposure to ionizing radiation is a well-established risk factor for the development of thyroid malignancies. Given the fact that the thyroid gland is a particularly radiosensitive organ and consequently vulnerable to radiotherapy in the head and neck area, our review aims to summarize the related risk factors of second primary thyroid cancer development and exposure to ionizing radiation.

Methods: A comprehensive literature search was performed in MEDLINE (PubMed), Scopus, and Cochrane Central Register of Controlled Trials (CENTRAL) databases.

Results: Dose and field of radiotherapy, age at the time of exposure, sex, and primary disease constitute the main subjects of our study, confirming the etiological connection between head and neck radiotherapy and malignant thyroid neoplasm.

Discussion: Although these risk factors contribute to the occurrence of thyroid malignancies after radiotherapy, ongoing investigation is required to define the individual effects of these factors and their combined influence on carcinogenic pathways.

Conclusion: In this review, we underscore the relevance of known risk factors, thus highlighting the importance of tailored follow-up strategies in patients undergoing radiotherapy of the head and neck area. In the era of advanced radiotherapy (RT) techniques and more effective screening tools, many questions may arise about the impact of technological advantages on the incidence of second primary thyroid malignancies.