PURPOSE: The aim of this study was to clinically validate a multivariable normal tissue complication probability (NTCP) model for grade 2-4 swallowing dysfunction at 6months after radiotherapy or chemoradiation (SWALM6) in @entity135 @entity1 treated with swallowing sparing intensity modulated radiotherapy (SW-IMRT) and to test if SW-IMRT resulted in a reduction of the prevalence of SWALM6. MATERIALS AND METHODS: The primary endpoint was SWALM6. For all 186 @entity1 , a standard IMRT (parotid sparing) and a SW-IMRT plan (additional constraints for swallowing organs at risk) was created. The difference in NTCP for SWALM6 (  NTCPSWALM6=NTCPstandard-NTCPSW-IMRT) was calculated. @entity1 were treated with SW-IMRT. The external validation of the NTCP model was analyzed by comparing performance measures. RESULTS: The mean   NTCPSWALM6 was 4.9% (range 0.01-17.3%), with a significant lower mean predicted NTCPSW-IMRT of 22.6% (95% CI 20.2-24.9%), compared to NTCPstandard of 27.5% (95% CI 24.9-29.9%) (p<0.001). There was a perfect correspondence of NTCPSW-IMRT with the observed prevalence of SWALM6 (22.6%). The overall model performance, discrimination and 'goodness of fit' were good. CONCLUSION: We externally validated the multivariable NTCP model for SWALM6 in SW-IMRT treated @entity1 , showing reduced swallowing dysfunction by reducing the dose parameters included in this NTCP model.

Swallowing sparing intensity modulated radiotherapy (SW-IMRT) in XXXX : Clinical validation according to the model-based approach.

@entity1 :: ('9606', 'Species') :: ['patients', 'Patients'] @entity135 :: ('MESH:D006258', 'Disease') :: ['head and neck cancer']
@entity135 :: (MESH:D006258,Disease) :: ['head and neck cancer']
