Defining physician acceptance of radiosensitivity testing for guiding therapeutic interventions in head and neck cancer: A Delphi consensus study

Background: Radiosensitivity biomarkers hold promise for personalized radiotherapy but their clinical maturity and acceptability remain uncertain in head and neck cancer (HNC). This study assessed expert consensus on the potential integration of radiosensitivity testing and Normal Tissue Complication Probability (NTCP) modeling to inform therapeutic and supportive decisions. Material and methods: A Delphi consensus survey was conducted among HNC specialists to evaluate perceptions of clinical applicability, validation requirements, and integration of radiosensitivity testing to guide therapeutic interventions, including test-guided treatment modifications and combination with NTCP models. Results: A clear distinction emerged between supportive-care interventions and radiosensitivity test-guided treatment adaptations. Experts agreed that the current level of maturity of radiosensitivity biomarkers and NTCP modeling does not support major changes to primary treatment decisions outside clinical trials. Ten statements reached consensus, including IMRT as standard, individualized nutritional follow-up, and post-treatment surveillance as routine practice; one reached rejection. Partial agreement was observed for radiosensitivity testing in complex cases and for proton referral in high-risk patients, while preventive gastrostomy showed no consensus. Supportive-care measures were consistently considered acceptable in routine practice, whereas biomarker-guided treatment adaptations were mainly supported within clinical trials. External validation confirmed high concordance for supportive-care items and moderate support for trial-based biomarker-guided strategies. Conclusions: Experts considered radiosensitivity testing and NTCP modeling as promising yet not ready for routine therapeutic decision-making. Supportive-care interventions are widely accepted in routine HNC practice, whereas radiosensitivity test-guided treatment adaptations remain investigational and should currently be evaluated within clinical trials.