Scintigraphic evaluation of long-term salivary function after bilateral whole parotid gland irradiation in radiotherapy for head and neck tumour

• Published in: Oral oncology Vol. 34; no. 2; pp. 140 - 146
• Main Authors: Kaneko, M., Shirato, H., Nishioka, T., Ohmori, K., Takinami, S., Arimoto, T., Kagei, K., Miyasaka, K., Nakamura, M.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.03.1998; Elsevier
• Subjects: Acute Disease; Adolescent; Adult; Aged; Biological and medical sciences; Carcinoma, Squamous Cell - radiotherapy; Chronic Disease; Chronic xerostomia; Dose-Response Relationship, Radiation; Ent. Stomatology; Female; Follow-Up Studies; Head and Neck Neoplasms - radiotherapy; Humans; Investigative techniques, diagnostic techniques (general aspects); Late recovery; Male; Medical sciences; Middle Aged; Parotid Gland - diagnostic imaging; Parotid Gland - radiation effects; Prognosis; Radionuclide Imaging; Radionuclide investigations; Radiotherapy - adverse effects; RI sialography; Salivary function; Subacute xerostomia; Xerostomia - diagnostic imaging; Xerostomia - etiology; Late recovery; Salivary function; Chronic xerostomia; Subacute xerostomia; RI sialography; Radionuclide study; Human; Squamous cell carcinoma; Radiodiagnosis; Sialography; Secretion; Bilateral; Exploration; Salivary gland; Malignant tumor; Scintigraphy; Radiotherapy; Long term; Head and neck; Medical imagery; ENT disease; Bibliographic review
• ISSN: 1368-8375; 1879-0593
• DOI: 10.1016/S1368-8375(97)00087-0

In 25 patients with head and neck tumour, in whom bilateral whole parotid glands were totally included in the irradiation volume, parotid gland function was estimated and compared with that of 58 non-irradiated parotid glands in 29 patients, by symptomatic grading and radioisotope (RI) sialography. Sequential follow-up by RI sialography has suggested that if the total dose to the parotid gland is less than 52 Gy or if the time-dose fractionation (TDF) value is less than 80, then partial recovery of salivary function can be expected 1 or 2 years after irradiation, even if patients show severe xerostomia during the first 6 months. Long-term recovery rarely occurs in parotid glands which have been irradiated at doses exceeding 55 Gy or with TDF values of 88 or higher. The 50% complication probability ( ed 50) was less than 33 Gy for subacute xerostomia during the first 6 months and 52.5 Gy for chronic xerostomia after 12 months, respectively. Although a prospective study will be required for confirmation, differences between the dose-response curves of xerostomia at subacute and chronic phases suggest a basis in different biological mechanisms.