This study aimed to assess the prevalence and risk factors associated with late xerostomia and hyposalivation in head and neck cancer (HNC) patients after radiotherapy (RT).

An observational, multicentric cross-sectional study was conducted on 260 HNC patients attending various radiation centers for follow up 1-year post-treatment. Clinical assessments included the Subjective Dry Mouth Score (SXI), Clinical Oral Dryness Score (CODS), and Unstimulated Salivary Flow Rate (UWS).

Xerostomia was reported by 78% of patients, with higher severity in those over 50 years (Mean ± SD: 13.53 ± 1.09). Women showed lower salivary flow (UWS: r = 0.556, p < 0.0001) and higher xerostomia scores (SXI: r = 0.337, CODS: r = 0.359) than men. Tumor site correlated strongly with xerostomia (SXI: r = 0.894, p < 0.001), with oral cavity tumors showing more severe effects than nasopharyngeal tumors. Higher RT dose and fraction were negatively associated with UWS (r = -0.537, p < 0.0001) and positively correlated with SXI (r = 0.293) and CODS (r = 0.405, p < 0.0001). The regression models showed that xerostomia severity is significantly predicted by advanced tumor stage, female gender, older age, and higher radiation dose exposure.

The study reveals a high prevalence of xerostomia and hyposalivation among HNC survivors. Increased xerostomia severity and decreased salivary flow were significantly associated with advanced tumor stage, higher radiation doses, and concurrent chemoradiotherapy.

Understanding risk factors can guide early interventions and personalized management to enhance long-term oral health outcomes.