Effect of selenium supplementation for protection of salivary glands from iodine-131 radiation damage in patients with differentiated thyroid cancer.
OBJECTIVE
In the current study, we examined whether selenium supplementation during iodine-131 (131I) treatment had a radio-protective effect on salivary glands.


METHODS
Sixteen patients with differentiated thyroid cancer were prospectively enrolled in the study. Patients after total thyroidectomy, before131I treatment, were divided into two groups; 8 patients in the selenium group and 8 patients in the control group. Patients in the selenium group received 300νg of selenium orally for 10 days, from 3 days before to 6 days after131I treatment. The control group received a placebo over the same period. To assess salivary gland function, salivary gland scintigraphy was performed before and 6 months after131I treatment. Serum amylase and whole blood selenium levels were measured before and 2 days and 6 months after131I treatment. Using salivary gland scintigraphy, maximum uptake ratio (MUR), maximum secretion percentage (MSP), and ejection fraction (EF) of each salivary gland were calculated.


RESULTS
Baseline clinical characteristics, baseline amylase and selenium levels, and parameters of baseline salivary gland scintigraphy were not significantly different between selenium and control groups (P>0.05). On a blood test performed 2 days after131I treatment, the selenium group showed a significantly higher whole blood selenium level (P=0.008) and significantly lower serum amylase level (P=0.009) than the control group. On follow-up salivary gland scintigraphy, the control group showed significantly decreased, MUR of the bilateral parotid and left submandibular glands, MSP of the bilateral parotid and submandibular glands, and EF of the left submandibular glands (P<0.05), while the selenium group only had a significant decrease in MSP of the right submandibular gland and EF of the left submandibular gland (P<0.05).


CONCLUSIONS
Selenium supplementation during131I treatment was effective to reduce salivary glands damage by131I radiation in patients with differentiated thyroid cancer.
Catholic Kwandong University International St. Mary's Hospital, 25, Simgok-ro 100 beon-gil, Seo-gu, Incheon, 404-834, Korea. jwlee223@ish.or.kr.
Haiyoung
H
Son
Sang Mi
SM
Lee
Ra Gyoung
RG
Yoon
Hakmin
H
Lee
Ilkyun
I
Lee
Soon
S
Kim
Woong Youn
WY
Chung
Jeong Won
JW
Lee
D000284:Administration, Oral; D000328:Adult; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000009:adverse effects* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D011832:Radiation Injuries / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control*; D011837:Radiation-Protective Agents / Q000008:administration & dosage; D019275:Radiopharmaceuticals / Q000009:adverse effects / Q000627:therapeutic use; D012643:Selenium / Q000008:administration & dosage*; D012793:Sialadenitis / Q000209:etiology* / Q000517:prevention & control*; D016037:Single-Blind Method; D013964:Thyroid Neoplasms / Q000150:complications / Q000532:radiotherapy*; D016896:Treatment Outcome
D007457:Iodine Radioisotopes; D011837:Radiation-Protective Agents; D019275:Radiopharmaceuticals; D012643:Selenium