Randomized controlled trial of semi-individualized 3D-printed tissue retraction devices vs. standard shielding splints in head and neck cancer treated with intensity-modulated and particle radiotherapy (GUARD).

BACKGROUND AND PURPOSE: This randomized controlled trial evaluated whether tissue-retraction devices (TRDs) lessen severe radiation-induced oral mucositis (RIOM) versus standard flexible intraoral shielding splints (IOS) in patients receiving intensity-modulated radiotherapy (IMRT), carbon-ion RT, or combined-modality RT for head-and-neck cancer (HNC). Although TRDs may spare normal tissue, randomized evidence with an active control under contemporary RT techniques remains scarce.

MATERIALS AND

METHODS

HNC patients requiring RT at University Hospital Heidelberg (2020-2023) were randomized 1:1 to receive a semi-individualized, 3D-printed TRD or standard IOS. The primary outcome was severe RIOM (RTOG/CTCAE grade ≥3) at RT completion, assessed by video endoscopy in a predefined region adjacent/opposite to the clinical target volume. Secondary endpoints included acute and late toxicities, patient-reported outcomes (PROs), and dosimetric comparisons of organs at risk, including the tongue and palate.

RESULTS

Of 34 randomized patients, 29 were evaluable (225 regions assessed). TRD significantly reduced the rate of RIOM grade ≥3 with 0/13 TRD vs. 9/16 IOS patients affected (p < 0.001). Grade 1-2 RIOM occurred in 7 (54 %) TRD vs. 2 (12 %) IOS. Among patients with tumors above the oral cavity, TRD significantly reduced tongue mean dose (median Dmean: 16.71 Gy [IQR: 2.41-20.71] vs. 29.26 Gy [IQR: 21.56-42.52]; p = 0.034). PROs trended toward less oral pain and swallowing difficulty with TRD.

CONCLUSION

TRD reduced severe RIOM in displaced normal tissues while improving tongue and palate dosimetry. Findings support TRD integration into clinical practice, though larger trials are needed to assess long-term patient-reported benefits and large-scale implementation.

TRIAL REGISTRATION: NCT04454697.