Radiation-induced parotid gland changes in oral cancer patients: correlation between parotid volume and saliva production.
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 cm(3) (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.
Teshima
Keiko
K
Department of Oral and Maxillofacial Surgery, Kumamoto University Hospital, Kumamoto, Japan.
Murakami
Ryuji
R
Tomitaka
Etsuji
E
Nomura
Tomoko
T
Toya
Ryo
R
Hiraki
Akimitsu
A
Nakayama
Hideki
H
Hirai
Toshinori
T
Shinohara
Masanori
M
Oya
Natsuo
N
Yamashita
Yasuyuki
Y
D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000532:radiotherapy*; D009929:Organ Size; D010306:Parotid Gland / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects*; D012189:Retrospective Studies; D012463:Saliva / Q000378:metabolism*