KEY POINTS
- This prospective cross-sectional study enrolled 95 head and neck cancer survivors in remission after curative radiotherapy; 90 had complete dosimetry for NTCP modeling. Median interval from treatment to assessment was 24.5 months, and 62.2% had oropharyngeal primaries.
- Patients completed a 22-item Scleroderma Skin Patient-Reported Outcome questionnaire adapted to neck fibrosis. Symptom burden was classified as mild in 64.4%, moderate in 20.0%, and severe in 15.6%.
- SSPRO showed moderate-to-strong relationships with established EORTC quality-of-life instruments and was designed to capture fibrosis-specific problems that conventional head and neck questionnaires may underestimate.
- In patients without previous neck surgery, increasing dose to skin, sternocleidomastoid muscle, and subcutaneous tissue was associated with worse fibrosis-related patient-reported outcomes.
- Prior neck surgery substantially complicated the dose–response relationship. Surgically treated patients reported greater fibrosis burden, making radiation-specific NTCP estimation substantially less robust in this subgroup.
- The investigators generated exploratory Lyman–Kutcher–Burman models and candidate dose constraints for these previously unmodeled neck tissues and showed through replanning examples that dose reduction could be technically feasible.
- The proposed thresholds were derived within a single institution and have not undergone external or prospective validation; they should therefore not yet be treated as routine planning constraints.
CLINICAL TAKEAWAY
Neck fibrosis may be amenable to the same patient-reported, dose–response planning approach already used for xerostomia and dysphagia. The proposed constraints are not ready for routine optimization, particularly after neck surgery, but they provide a concrete framework for prospective fibrosis-sparing trials.