Thyroid depression following splenic irradiation in lymphoma patients.

Abstract

SUMMARYIrradiation of lymphomatous tissue may be followed by inactivation of TSH leading to depressed thyroid uptake tests. Three patients with malignant lymphomas with enlarged spleens were given radioactive iodine thyroid uptake tests before and during splenic irradiation. A significant depression of their thyroid uptakes was observed. Two patients with a myeloproliferative form of polycythaemia were given irradiation to enlarged spleens without significant depression of their thyroid uptakes.It was concluded that radiotherapy caused breakdown of lymphomatous tissue in the spleens, leading to increased inactivation of TSH. A similar depression of thyroid uptakes was reported previously following irradiation of peripheral lymphadenopathy.In contrast, epigastric irradiation in lymphoma patients elevated their thyroid uptakes, in some cases to above‐average levels. It is suggested that a separate direct effect of radiation on the autonomic nervous system was able to cancel out the anti‐TSH effect of breaking down lymphomas. Evidence for an effect on the autonomic nervous system was shown by a decrease in night sweats and antidepressant trends in patients having neck irradiation. Two patients with lymphomas and depressive psychosis had sustained remissions of their mental symptoms following irradiation to the lower neck.