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Japanese Journal of Clinical Oncology

Year: 2010  |  Volume: 40  |  Issue: 1  |  Page No.: 42 - 46

Radiation-induced Parotid Gland Changes in Oral Cancer Patients: Correlation Between Parotid Volume and Saliva Production

K Teshima, R Murakami, E Tomitaka, T Nomura, R Toya, A Hiraki, H Nakayama, T Hirai, M Shinohara, N Oya and Y. Yamashita

Abstract

Objective

To evaluate whether saliva production reflects the parotid volume during the course of radiation therapy (RT) in patients with head-and-neck cancer.

Methods

Twenty patients with advanced oral squamous cell carcinomas, who were treated with preoperative chemo-RT, underwent morphological assessment with CT or MRI and functional assessment with the Saxon test. For the Saxon test, saliva production was measured by weighing a gauze pad before and 2 min after chewing without swallowing; the low-normal value is 2 g. Saliva production and parotid volumes before and 2 weeks after RT were compared with the paired t-test, the Spearman rank correlation test and the Fisher exact test.

Results

After 30 Gy irradiation, mean saliva production was decreased from 4.2 to 1.0 g (P < 0.01); the reduction in saliva production ranged from 1.7 to 5.4 g (mean 3.2 g). The mean parotid volume was decreased from 68.2 to 47.9 cm3 (P < 0.01); the post-RT:pre-RT parotid volume ratio ranged from 54% to 85% (mean 71%). Although the initial parotid `volume was correlated with initial saliva production (r = 0.47, P = 0.04), no significant correlation was noted after RT (r = 0.08, P = 0.71), and there were considerable individual variations. The parotid volume ratio was inversely correlated with the saliva-reduction amount (r = – 0.79, P < 0.01).

Conclusions

There was a correlation between decreased parotid gland volume and decreased saliva production in patients with head-and-neck cancer undergoing RT. Parotid volume reduction may predict parotid gland function.

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