The Metabolic Profile Post a Dosimetry-Guided I-131 Therapy in Patients with Metastatic Differentiated Thyroid Cancer

Program: Abstracts - Orals, Poster Previews, and Posters
Session: SAT 270-310-Thyroid Neoplasia (posters)
Saturday, April 2, 2016: 1:15 PM-3:15 PM
Exhibit/Poster Hall (BCEC)

Poster Board SAT 304
Athanasios Bikas*1, Afroditi Boulougoura2, Faryal Mirza3, Shivangi Vachhani4, Leonard Wartofsky5, Douglas Van Nostrand5 and Kenneth Burman5
1Medstar Health Research Institute/ Washington Hospital Center, Washington, DC, 2MedStar Washington Hospital Center, Chevy Chase, MD, 3MedStar Washington Hospital Center, 4Georgetown University Hospital, Alexandria, VA, 5MedStar Washington Hospital Center, Washington, DC
Introduction: Dosimetry is used to determine the maximum tolerated activity (MTA) of I-131 for the treatment of metastatic differentiated thyroid cancer. It is well established that I-131 therapy can result in hematopoietic toxicity, but whether I-131 has an effect on the metabolic profile of patients has not been examined.

Objective: To evaluate whether dosimetry-guided I-131 treatment affects the liver and renal function of patients with differentiated thyroid cancer.

Methods: A retrospective analysis was performed on 50 patients with differentiated thyroid cancer who had a dosimetry-guided I-131 therapy. Paired t-tests were used for the analysis of the differences in the averages of all constituents of Complete Metabolic Profile (CMP) that were documented at baseline, 1, 6, and 12 months post-131I therapy.

Results: The 50 patients with differentiated thyroid cancer that were included in the study had a mean age of 54±17.2 years. 72% (36/50) had papillary, and 28% (14/50) had follicular thyroid cancer. The mean dosimetry-guided dosage of I-131 that they received was 293.1±97.3 mCi. The Blood Urea Nitrogen was minimally elevated at all time points (15.7±5.3 at 1 month, 15.4± 4.8 at 6 months, and 15.1±4.6 at 12 months post-I-131) when compared to baseline (14.84±6.2), but no statistically significant differences were documented (p values 0.41, 0.79 and 0.89 respectively). Likewise, the serum creatinine was not affected by I-131 administration ( p values 0.09, 0.08 and 0.25 at 1, 6 , and 12 month respectively). We also examined the liver function in this cohort of patients. Both transaminases (AST and ALT) did not demonstrate statistically significant differences when we compared the values at 1, 6 and 12 months to the baseline values. Alkaline phosphatase was not altered by the administration of I-131 (p values of 0.81, 0.94 and 0.55 respectively). No clinically significant electrolyte abnormalities were noticed to be caused by I-131. Finally, when we compared patients that were prepared with recombinant human TSH (rhTSH) (N=31) to patients that were prepared with thyroid hormone withdrawal (THW) (N=19) for their dosimetry-guided I-131, no difference was found in any of the parameters examined.

Conclusion: This study evaluated the effects of dosimetry-guided (high activity) I-131 treatment on the CMP of patients with differentiated thyroid cancer at multiple time points over the first year post-I-131. The results indicate that I-131 does not adversely affect the liver and renal function of these patients. Finally, the method of preparation for I-131 therapy did not affect the metabolic profile in the examined cohort of patients.

Nothing to Disclose: AB, AB, FM, SV, LW, DV, KB

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