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[Effect of parotid sparing intensity modulated radiation therapy on salivary composition, flow and dry mouth prevention].

PURPOSE
To investigate the changes of salivary composition, flow and dry mouth in patients with head and neck squamous cell carcinoma after parotid sparing modulated radiation therapy.


METHODS
One hundred and one patients with head and neck squamous cell carcinoma who received radiotherapy in Qingyang People's Hospital from May 2016 to November 2018 were selected and divided into intensity modulated radiation group(n=54) and conventional radiation group(n=47) according to different treatment methods. The clinicopathological parameters, parotid uptake index, salivary composition, dry mouth, oropharyngeal symptoms and grading were compared between the two groups. The data were analyzed with SPSS 20.0 software package.


RESULTS
The tumor site, TNM stage and differentiation had no significant difference between the two groups(P>0.05). The concentration of total protein, secretory IgA, calcium and phosphorus in saliva of patients in intensity modulated radiation therapy group were significantly higher than those in conventional radiation group(P<0.05). The parotid uptake index, secretion index and salivary flow velocity were significantly decreased in both groups(P<0.05), and were significantly lower in the conventional radiation group than in the intensity modulated radiation group(P<0.05). Dry mouth condition in intensity modulated radiation group was significantly better than that in conventional radiation group(P<0.05). After treatment, the ratio of pharyngalgia and dysphagia patients in the intensity modulated radiation group was significantly lower than that in the conventional radiation group(P<0.05). The degree of oropharyngeal grading in the intensity modulated radiation therapy group was significantly better than that in the conventional radiation group(P<0.05).


CONCLUSIONS
The application of parotid sparing retention modulated radiation therapy has little effect on salivary composition, flow rate and dry mouth, and has obvious protective effect on parotid secretion.