Endocrine Abstracts

Thyroid cancers constitute 2% of all cancer cases most of which are differentiated. Tumor size, lymph node metastases and thyroglobulin levels (Tg) in the follow-up period are among the major factors responsible for recurrence. In this study, we aimed to review our series of differentiated thyroid cancers and establish the risks of recurrence.

This study was carried out through a retrospective analysis of 393 differentiated thyroid cancer cases that were diagnosed in our department between January 2000 and December 2010. The demographic characteristics of the study group are seen in Table 1.

In the patients who had initial pathological lymphadenopathy, the recurrence risk was 2.76 times compared to the cases without pathological lymphadenopathy (P<0.001). The recurrence rate of male cases is 21 (30.4%). The cases with capsule invasion had 2.01 times increased risk of recurrence (P=0.002). The average tumor diameter in the 82 cases which relapsed was 2.04±1.63 cm, and the average tumor diameter in the 311 cases under remission was 1.45±1.21. A 1 cm increase in the tumor diameter increased the recurrence risk by 25% (P<0.001). Two hundred and eighty of the cases (71.2%) were multinodular, 108 of them 38.6% were multifocal, and multinodularity increased risk of recurrence 1.93 times (P=0.021). A postoperative Tg (pre-radioactive iodine (RAI) ablation therapy) value ≥2 ng/ml increased the recurrence risk and mortality significantly (P=0.003, P=0.04 respectively). Stimulated Tg values ≥2 ng/ml 6–12 months following RAI treatment increased the risk of recurrence (P<0.001). Disease-free survival was also significantly shorter in this group (P<0.001). A suppressed Tg value ≥0.3 ng/ml in the 6–12 months period following the first whole-body scan was associated with relapse (P<0.001). Serum Tg ≥ 5.6 ng/ml in early postoperative period increased the risk of recurrence 2.38 times (P=0.002). Excluding postoperative anti-Tg (+) cases, stimulated Tg values >0.285 ng/ml had 3.087 times increased likelihood of recurrence (P<0.001).

In our study, we established that tumor diameter, male sex, lymph node metastasis, stage III and higher stage, presence of capsule invasion, increase in the nodule size that was initially measured with ultrasonography, postoperative Tg values higher than ≥2 ng/ml, suppressed Tg higher than ≥0.3 ng/ml, stimulated Tg ≥2 ng/ml, stimulated serum Tg ≥0.285 ng/ml in anti-Tg(−) cases, serum Tg ≥5.6 ng/ml in the postoperative scan increased the recurrence risk. We recommend that these factors are kept under consideration in patient follow-up.