Toxicity and Quality of Life After Locoregional Radiotherapy in Patients With Thyroid Cancer

Locoregional external beam radiotherapy (EBRT) is selectively used in thyroid cancer patients to induce locoregional control. However, despite technological advances, EBRT remains associated with toxicities. We evaluated thyroid-cancer specific toxicities and long-term Quality of Life (QoL) post-EBRT.

EBRT-treated thyroid cancer patients at Universal Medical Centre Groningen (2007-2023) were retrospectively evaluated (n = 66). Acute (< 6 weeks) and late (≥ 3 months) toxicities and QLQ-H&N35 results, prospectively collected as standard patient care, were analyzed (available in 24/66). Additionally, 17/66 living patients cross-sectionally completed the QLQ-H&N43 [renewed QLQ-H&N35] and SF-36-RAND-36.

In 24/66 patients who completed questionnaires during EBRT treatment, most severe acute toxicities occurred around week 6 (91% dermatitis, 74% pain, 70% hoarseness, 65% dysphagia). Late toxicities included persisting acute toxicities and fibrosis. Six months post-treatment, only QLQ-H&N35 domains "social eating" (p = 0.031) and "dry mouth/sticky saliva" (p = 0.025) were affected, in comparison to pre-radiation. In the 10/17 patients who completed the QLQ-H&N35 6 months post-radiation and the cross-sectionally performed QLQ-H&N43, no long-term mitigation of assessed domains was identified in a longitudinal analysis. The most advanced EBRT technique was associated with better QLQ-H&N43 scores (p = 0.047).

EBRT causes acute and late toxicities in most thyroid cancer patients and may be associated with a decreased QoL. As these patients generally survive for multiple years, there is a compelling need to minimize toxicities with more refined radiation techniques, such as proton therapy.