Factors affecting discharge time of well differentiated thyroid cancer patients receiving 131I therapy: Five years’ experience

Introduction: The post-surgical management of patients with differentiated thyroid cancer include ablation of remnant local and distant metastatic tissues with 131I therapy, which accentuates isolation of the patient in order to avoid unnecessary radiation exposure to the care givers, general public and the environment. The duration of isolation is subject to the reduction of exposure to the safe limit as defined by the regulatory bodies. Methods: This study presents the correlation of isolation period of the radioiodine treated patients with administered activity, surgical endeavors and the disease extent. The study was conducted on 222 patients at the Institute of Radiotherapy and Nuclear Medicine (IRNUM), Peshawar, Pakistan from 2008-2012. Results: The number of patients in the four groups on the basis of 131I administered activity were, <3.7GBq (n=7), 3.7-5.55GBq (n=182), 5.59-7.4GBq (n=30) and ˃7.4GBq (n=3), while in the four surgical groups were, total thyroidectomy (n=116), subtotal thyroidectomy (n= 73), lobectomy (n=14) and unknown (n=19). Regarding the extent of the disease, the three defined groups were thyroid remnant (n=96), locally advance disease (n=88) and distant metastatic disease (n=38). It was found that 30.63% of patients were discharged after 48 hours of 131I administration while 27.03%, 24.32%, 10.81%, 6.31%, and 0.90% patients were kept in isolation for 72, 96, 120, 144 and 168 hours, respectively. Conclusion: The isolation period of radioactive 131I treated patients is directly related to the 131I activity administered, size of the remnant, and extent of the disease.