The influence of biological sex on thyroid cancer treatment risk assessment

• Background: Researchers are often reluctant towards using females in studies, especially when radiopharmaceuticals and hormonally dependent diseases are concerned. Simultaneously, women are more prone to thyroid-related diseases such as Grave’s disease and Hashimoto’s thyroiditis, with a 7-10 times higher incidence than in men. The thyroid gland synthesizes iodine-containing hormones, which are needed for several cellular processes in the body. I-131 is routinely used in thyroid cancer treatment, and I-131-containing pharmaceuticals are used for treatment of patients with some neuroendocrine tumor types. This study was performed to evaluate possible differences between sexes in tissue uptake of I-131 in mice. Methods: 35 male and 35 female mice (C57BL/6N, n=5/group) were intravenously injected with I-131 at 8 am, and animals were killed 1 h to 7 d after injection. Tissue samples were collected, weighed, and measured to determine I-131 activity concentration. Results: The results indicate differences in I-131 uptake between males and females, especially in the salivary glands and kidneys. In the majority of the tissues and observed time points, statistical significant differences were found. The decrease of activity concentration in thyroid after 18 h was slower for females (statistical significant), though the obtained maximum uptake was similar. Conclusion: The I-131 uptake differs between males and females, which would result in different absorbed doses from exposure to the same amount of I-131. The difference in magnitude is tissue-dependent. The results suggest biological sex to be treated as a variable in dose calculations and risk assessments when treating cancer patients with radiopharmaceuticals containing I-131.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Radiologi och bildbehandling (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Radiology, Nuclear Medicine and Medical Imaging (hsv//eng)

Nyckelord

Biodistribution

sex difference

I-131

thyroid

C57BL

mice

dosimetry

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vet (ämneskategori)

kon (ämneskategori)