Serum markers for recurrence in patients with differentiated thyroid cancer after combined treatment and the retreatment results

<p><span style="font-family: Times New Roman;"><strong>Purpose:</strong> to analyze in a comparative perspective certain factors influencing recurrent differentiated thyroid cancer (DTC) in patients with an increasing concentration of serum thyroglobulin (Tg) and serum antithyroglobulin antibodies (TgA) in the blood serum.</span></p><p><span style="font-family: Times New Roman;"><strong>Patients and methods.</strong> The outcomes of 31 patients with a tumor marker of recurrent DTC after more than 6 months since the first radioiodine ablation (RAI) were analyzed. A follow-up on the group of patients was realized in the form of thyroid bed ultrasonography and dynamic control of Tg and TgA in the blood serum every 3 months during the first year after the first and second RAI and every 6 months later. The group selection criteria was the identification of a DTC recidivism tumor marker, which is characterized by the increase of more than 5 ng/ml in the face of synthetic thyroid hormone analogues intake and more than 2.5 ng/ml in the face of a suppressive therapy cessation, as well as an increase in titer in Al-TG over 20 IU/ml. The given values were regarded as a relapse of the disease after 6 months after the first RAI.</span></p><p><span style="font-family: Times New Roman;"><strong>Results.</strong> In 70% of all cases a tumor spread to the regional lymph nodes was found. 21% of relapses were observed in the group of patients with a level of TSH below 50 IU/ml. In 35% of cases the ultrasonography showed the presence of thyroid tissue in the thyroid bed projection and the enlargement of lymph nodes in the neck in 5 patients (16.61%) of relapses were identified in patients with an extraorganic spread of the tumor. In 30% of cases the first RAI activity was less than 3.0 GBq. A DTC recidivism tumor marker was observed more often 65 in patients with less than 5% of the RFID tags all over the body after the initial administration of the therapeutic activity of I¹³¹.</span></p><p><span style="font-family: Times New Roman;"><strong>Conclusion.</strong> Major risk factors for the DTC recidivism tumor marker are (1) save-on surgical stage of combined treatment, (2) the spread of a tumor process on regional lymph nodes in the neck, the presence of significant thyroid balance after the operation, according to thyroid scintigraphy, (3) insufficient profundity of hypothyroidism before RAI, (4) administration of activity of I¹³¹</span><span style="font-family: Times New Roman;"> less than 3.0 GBq with the first RAI, (5) ignoring the suppressive therapy regime after</span><span style="font-family: Times New Roman;"> RAI.</span>