Introduction: Radioactive iodine is the effective therapy in thyroid cancer. The aim of this study is to evaluate the serum tumor markers in patients under the therapy with radioactive iodine 131.
Material and Methods: A 45 cases of female patients aged 16-60 years with thyroid cancer surgery referred to the nuclear medicine department of Nemazi hospital for (iodine treatment after surgery) were selected. The selection was on the basis of interviewing and information of patients is consent forms. Only patients with thyroid cancer and referred for the first time without any other diseases were chosen for this study. The selected patients were prescribed a dose of 150 mCi of I-131. From each patient, 4 mL of chelated serum for serological studies on tumor markers and 2 mL of oxalated serum for spectrophotometry studies on cell death were used in three stages. The first stage before the iodine therapy, the second stage, after 48 hours, and the third stage, 30 days after radioiodine therapy were studied and the results were evaluated by the one-way repeated measures ANOVA test.
Results: According to the results of dependent paired T-Test, AFP, in the periods before, 48 hours and 1 month after radioiodine therapy, respectively were 3.46 ± 1.21 and 3.74 ± 1.37 and 3.76 ± 1.25 (p <0.0005). About CA 19-9 in the periods before, 48 hours and one month after radioiodine therapy, the results were 9.30 ± 6.32, 9.95 ± 6.92 (p = 0.040) and 11.26 ± 7.49 (p <0.0005) respectively. About CEA, the results were 1.60 ± 0.60, 1.47 ± 0.55 and 2.23 ± 0.69 (p <0.0005), respectively. In the case of tumor marker CA 15-3 results were 15.53 ± 6.48 and 1.60 ± 0.60 and 15.68 ± 6.52 (p = 0.014), respectively and in the case of ALP, results were 124.22 ± 5 and 122.2 ± 6 and 116.7 ± 7 (p <0.0005), respectively.
Conclusion: According to the same studies and the acquired results, it can be concluded that the tumor markers CEA and CA19-9 are more acceptable and sustainable for monitoring the malignancy and progressive disease in patients with thyroid cancer. The decreasing ALP is normal and transient. The increase of AFP and CA15-3 is not even statistically reliable. It is recommended that the period of iodine therapy and falsely elevated tumor markers can be informed to the doctor, during the gastrointestinal studies in patients with thyroid cancer, in order to prevent wrong decisions on the treatment process.