Nasolacrimal Duct Obstruction Secondary to Radioactive Iodine-131 Therapy for Differentiated Thyroid Cancer

Abstract

Deterministic effects of medical exposure to ionising radiation can be associated with both the effectiveness of treatment and adverse drug reactions to it. The latter may drastically deteriorate the quality of life of a patient after radionuclide therapy. In addition, the regulations of the Russian Federation require indicating the effective dose of radiation as a measure of damage (risk), but the presence of a deterministic effect in individual organs and tissues complicates monitoring and recording patient exposure doses. The aim of the study was to investigate the effect of radiopharmaceuticals containing 131 I on the development of secondary nasolacrimal duct obstruction (NLDO). Materials and methods : the study of secondary NLDO predictors analysed medical history data, post-therapy head-and-neck scintigrams, and methods to prepare patients for treatment. It involved sodium iodide, 131 I, formulated as a solution (marketing authorisation number: FS-002065) by the FSUE Federal Center of Nuclear Medicine Projects Design and Development of the FMBA of Russia. Results : the authors unambiguously localised the lacrimal ducts in post-therapy 131 I scintigrams of the head and neck and quantified 131 I uptake ratios for the lacrimal duct area. Also, they identified a set of NLDO predictors: the age of a patient, the administered activity, the administration of recombinant human thyroid-stimulating hormone, the 131 I uptake ratio, etc. The article describes a method for identifying the groups at risk of NLDO following radioiodine therapy for differentiated thyroid cancer. Conclusions : secondary NLDO is a deterministic effect of 131 I exposure. The authors have developed a new method for predicting secondary NLDO by a combination of the patient’s individual parameters and treatment plan; the identified predictors help to personalise radioiodine therapy. The authors suggest the following: to include information on secondary NLDO as a complication of therapy to the SmPC section on undesirable effects; to develop approaches to secondary NLDO prevention; and to improve the algorithms for reporting adverse events in case of delayed manifestation and those for following patients up in the medical organisations having administered the radiopharmaceutical or in other medical organisations being applied to for medical care afterwards.