Background
Retrospective single-institution study (University of Virginia). Head and neck carcinoma of unknown primary (CUP) treated with IMRT to a comprehensive mucosal + bilateral neck target. Tested whether comprehensive IMRT achieves high locoregional control while reducing long-term toxicity (esp. xerostomia) vs conventional RT.
Interventions and follow up
Treatment: IMRT covering bilateral neck and putative mucosal sites for unknown-primary head and neck SCC
Primary endpoint: Mucosal emergence, regional control, toxicity
mFollow up: NR
Primary endpoint: Mucosal emergence, regional control, toxicity
mFollow up: NR
Results
Locoregional control: High with comprehensive IMRT-based bilateral mucosal RT (quantitative figures NR in source)
Parotid sparing: Meaningful vs conventional whole-mucosal RT (WART), with lower grade 2+ xerostomia
Nodal control: Excellent with IMRT
Parotid sparing: Meaningful vs conventional whole-mucosal RT (WART), with lower grade 2+ xerostomia
Nodal control: Excellent with IMRT
Adverse events
Acute: Mucositis and dysphagia during treatment
Late: Xerostomia significantly reduced vs conventional RT via parotid sparing; dysphagia and aspiration remained concerns
Late: Xerostomia significantly reduced vs conventional RT via parotid sparing; dysphagia and aspiration remained concerns
Conclusions
IMRT for head and neck CUP maintains high locoregional control while reducing late xerostomia vs conventional whole-mucosal RT, by sparing at least one parotid gland through optimized dose distribution.
Key Limitations
Single-institution retrospective; small sample; follow-up not specified; comprehensive mucosal irradiation vs neck-only volumes debated; selection bias and absence of randomized comparison.
Clinical Context
Supports IMRT for head and neck CUP to reduce xerostomia while maintaining control. Optimal target volume (comprehensive mucosa + bilateral neck vs more limited ipsilateral approaches) remains debated, particularly with HPV/EBV-directed primary-site investigation now standard.