Background: Dysphagia is a distressing symptom during and after radiotherapy treatment in head and neck cancer (HNC) patients. The objective of this prospective study was to investigate whether swallowing sparing intensity modulated radiotherapy (SW-IMRT) reduces the occurrence of swallowing dysfunction compared to the standard IMRT (ST-IMRT).
Methods: We randomized, planned, and treated patients with HNC who needed whole neck irradiation using the simultaneous integrated boost (SIB) IMRT technique. Doses of 70, 60, and 54 Gy (over 33 daily fractions) were prescribed to the primary tumor, high-risk and low-risk regions, respectively. The postoperative cases received 60 and 54 Gy (over 30 daily fractions) to the high-risk planning target volume (PTV) and low-risk PTV. We contoured organs at risk related to swallowing dysfunction (SWOARs) in all cases. In the ST-IMRT group, parotids only were spared. In the SW-IMRT group, parotids and SWOARs outside the high-risk PTV were spared. Assessment of dysphagia included clinical and instrumental evaluation.
Results: One hundred forty-six patients ended their radiotherapy treatment. Dose distribution showed comparable PTV coverage and no difference in parotid glands sparing between the two groups. SWOARs dose reduction with SW-IMRT differs according to tumor location and its overlap with SWOARs. Using different assessment methods, SW-IMRT was associated with a lower occurrence of dysphagia up to one year after treatment. There was no difference between the two groups regarding acute dysphagia (p = 0.262), overall survival (p = 0.811), and disease-free survival (p = 0.876).
Conclusion: SW-IMRT is significantly better than ST-IMRT regarding a physician-rated and objective assessment of swallowing dysfunction at short- and long-term post-treatment follow-up.
Keywords: Head and neck cancer; ST-IMRT; SW-IMRT; SWOARs; dysphagia.