Radiotherapy-Induced Thyroid Dysfunction in Cancer Patients

Radiotherapy-induced thyroid dysfunction is a common and clinically significant late effect in patients receiving radiation for head and neck, breast and lymphoid malignancies. Injury to thyroid follicular cells and vascular damage within the gland can lead to a spectrum of dysfunction, from transient subclinical hyperthyroidism to overt hypothyroidism. Incidence varies widely—recent estimates suggest up to 40–50% of patients may develop hypothyroidism within two years of treatment—reflecting differences in radiation technique, dose distribution and follow-up intensity. Key risk factors include higher mean thyroid dose, small pretreatment thyroid volume, and the volume of thyroid receiving moderate to high radiation doses. Modern radiotherapy planning and normal tissue complication probability modelling aim to personalise dose constraints to preserve thyroid function, while emerging predictive algorithms promise to refine surveillance and early intervention strategies. Global efforts now focus on integrating dosimetric thresholds into treatment planning and on multidisciplinary follow-up to mitigate long-term endocrine sequelae.

Research from Nature Portfolio

Recent studies have harnessed machine learning to stratify patients by risk of thyroid dysfunction after radiotherapy. One analysis applied decision trees, support vector machines and random forest algorithms to data from head and neck cancer cohorts. Five key predictors—patient age, pretreatment thyroid volume, mean thyroid dose, V50 and V60—emerged consistently across models. Older age and larger thyroid volume correlated with lower risk, whereas higher average dose and greater volumetric exposure at 50 Gy and 60 Gy increased the likelihood of hypothyroidism. The random forest model achieved the highest predictive accuracy (82.4%) and an area under the receiver operating characteristic curve of 0.827, underscoring the potential of ensemble learning to guide individualised monitoring and prophylactic treatment planning.

Radiotherapy-Induced Thyroid Dysfunction in Cancer Patients publication trend

The graph below shows the total number of articles in radiotherapy-induced thyroid dysfunction in cancer patients across all publications each year (not limited to Nature Index journals).

Technical terms

Intensity-modulated radiotherapy (IMRT): A radiotherapy technique that modulates beam intensity to conform the dose to the target while sparing adjacent normal tissues.

Dose-volume histogram (DVH): A graphical representation showing the percentage of an organ or volume receiving at least a specified radiation dose.

Vxx: The percentage volume of the thyroid gland receiving at least xx Gy of radiation.

VSxx: The absolute volume of thyroid spared from receiving at least xx Gy of radiation.

Random forest: A machine learning ensemble method that constructs multiple decision trees to improve predictive performance and robustness.

References

1. Evaluating the influence of anti-PD-1 immunotherapy combined with IMRT on thyroid dysfunction in nasopharyngeal carcinoma. Frontiers in Immunology (2025).
2. Hypothyroidism following Radiotherapy for Head and Neck Cancer: A Systematic Review of the Literature and Opportunities to Improve the Therapeutic Ratio. Cancers (2023).
3. Using machine learning algorithm to analyse the hypothyroidism complications caused by radiotherapy in patients with head and neck cancer. Scientific Reports (2023).
4. Thyroid dose‐volume thresholds for the risk of radiation‐related hypothyroidism in nasopharyngeal carcinoma treated with intensity‐modulated radiotherapy—A single‐institution study. Cancer Medicine (2019).