A study of thyroid function in cancer cachexia.

The mechanisms responsible for cancer cachexia have not yet been clarified. To further investigate the role played by the hypothalamic-pituitary-thyroid axis in cancer cachexia, we evaluated serum levels of T3, FT3, T4, FT4, TSH and TBG in a group of 26 cancer patients, 14 of whom showed cachexia, whereas the other 12 had a body weight within the normal range despite their advanced diseases. As controls, 58 healthy subjects and 11 patients with benign weight loss were included in the study. Low levels of both T3 and FT3 were observed in all patients with benign weight loss and in 9/12 advanced cancer patients who had no cancer cachexia. On the contrary, only 4/14 cachectic cancer patients presented decreased values of T3 and FT3. Moreover, the mean serum levels of T3 and FT3 in cachectic oncologic patients were significantly higher than those seen both in non-cachectic cancer patients and in patients with benign weight loss. Since T3 is the biologically active thyroid hormone, the lack of a decrease in its production might play a role in the pathogenesis of cancer cachexia.