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December 13, 1976

Thyroid Supplements and Breast Cancer

Author Affiliations

Loyola University Stritch School of Medicine Chicago

JAMA. 1976;236(24):2743. doi:10.1001/jama.1976.03270250013004

To the Editor.—  The article of Drs Kapdi and Wolfe and subsequent reporting in the media seems, to us, to represent an incorrect review and analysis of what is already documented with respect to thyroid disease and the incidence of breast cancer in man. Contrary to what was concluded, namely, that thyroid therapy is associated with a higher incidence of breast cancer, we believe it should be concluded that there is a higher incidence of breast cancer in women with preexisting and frequently inadequately treated hypothyroidism or thyroiditis.Several published reports now suggest that failure to adequately treat hypothyroidism, goiters, or thyroiditis with thyroxin leads to enhanced development of breast cancer in susceptible persons.1-5 There are, for example, confirmed reports of an increased incidence of breast cancer in hypothyroid patients1 and in patients with Hashimoto thyroiditis,2 and a greater incidence of elevated thyroidstimulating hormone (TSH) levels, an indication