At the time of radiation therapy for head and neck tumors, not only the major salivary glands but also many salivary glands are included in irradiation field. Consequently xerostomia are manifested in many of patients by degrees and oligosialia or asialia is objectively recognized. After the interstitial radiation therapy with or without external radiation therapy for the treatment of cancer of tongue and floor of the mouth, patients complain pain and/or swelling in submandibular region as often seen in the sialolithiasis.
Sialographic changes of the major salivery glands after radiation therapy were analysed.
Twenty six patients undergone radiation therapy for head and neck cancers were put into this study. Seven had carcinoma of oropharynx, six had carcinoma of tongue, three had carcinoma of nasopharynx, three had carcioma of salivery glands and seven has other malignant tumors.
The contrast medium used is 76% Urographin.
Sialographic findings were investigated concerning two major salivary glands: submandibular and parotid gland.
Submandibular glands: Stricture of Warton's duct was the main early findings after interstitial radiation therapy. Rupture of Warton's duct and/or atrophic change of submandibular gland often observed with time.
Parotid glands: No remarkable sialoglaphic change was detected in any time after external radiation therapy of 4000 rad (40Gy). Stricture of Stensen's duct was the most predominant findings at 6 months later since the completion of external radiation therapy of 6000 rad (60Gy), and the findings further progressed with time. After the completion of external radiation therapy of 8000 rad (80Gy), rupture of Stensen's duct and atrophic change of parotid gland were observed.
As survival rate of head and neck cancers was increased by radiation therapy, various side effects were also recongnized. Careful consideration must be needed on the treatment planning so as to minimize the late damages.