Investigation of risk factors that define recurrence in patients with differential thyroid cancer

Thyroid cancers constitute 2%of all cancer cases and differentiated thyroid cancer originating from follicular epithelial cells make up 85%of all thyroid cancer cases. Our study aims to investigate the factors that affect the thyroid cancer recurrence in individuals with differentiated thyroid cancer. This study was carried out through retrospective review of 393 differentiated thyroid cancer cases that were diagnosed with thyroid cancer at the Endocrinology Department of Başkent University Faculty of Medicine between January 2000 and December 2010 and followed-up for more than 6 months. The age at the time of diagnosis, sex, maximum tumor size, presence of lymph node invasion, multicentricity, multinodularity, presence of capsule invasion, histological subtype, presence of histological thyroiditis, surgical type, levothyroxine withdrawal in whole body iodine scan or RhTSH usage status, the number of cases that were recommended PET scan during their follow-ups, postoperative thyroglobulin and antithyroglobulin values, thyroglobulin and antithyroglobulin values in the TSH>30 uIU/ml period at the scan 6-12 months later, thyroglobulin and antithyroglobulin values in the TSH suppressed period 6-12 months after the radioactive iodine treatment, duration of follow-up, and recurrence status were recorded from hospital records and patient files, and recurrence and overall survival were determined. There was recurrence in 82(20.9%) of the patients. Histopathological analysis indicated papillary carcinoma in 362 (92.1%) cases, follicular carcinoma in 31 (7.9%) cases. In the assessment in accordance with the AJCC-2002 staging system, 328 (83.5%) of the total 393 cases had Stage I, 32(8.1%) had Stage II, 27 (6.9%) had Stage III, and 6 (1.5%) had Stage IVA disease. 324 of our cases were female, and 69 were male. In the patients who had initial pathological lymphadenopathy, the increase in the risk of recurrence was increased 2.76 times compared to the cases without pathological lymphadenopathy (p<0.001). The cases with capsule invasion had 2.01 times increased risk of recurrence (p=0.002). In the evaluation of tumor sizes of the 393 cases according to their histopathologies, the average tumor diameter in the 82 cases in which recurrence took place was 2.04±1.63 cm, and the average tumor diameter in the 311 cases without recurrence was 1.45±1.21, according to these results, a 1cm increase in the tumor diameter caused a 25%increase in the risk of recurrence (p<0.001). 280 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). There was a significant association between postoperative thyroglobulin (preRAI) value being ≥2 ng/ml and recurrance (p=0.003), examined with kaplan meiers analysis and survival analysis there was a decrease in survey in cases with thyroglobulin ≥2 ng/ml (p=0.004). There was a significant association between thyroglobulin with stimulated TSH (in the 6-12 months following RAI treatment and before WBIS) value ≥2 ng/ml and recurrence (p<0.001); disease free survival analysis was carried out with kaplan meiers and the survival time in cases with thyroglobulin ≥ 2 ng/ml was found to be significantly decreased (p<0.001). There was a significant association between the thyroglobulin with Suppressed TSH (in the follow up between the 6-12 months following the first WBIS) value ≥0.3 ng/ml and recurrence (p<0.001), kaplan meiers survival analysis was performed for disease free survival and decrease in survey was found in cases with thyroglobuline ≥0.3 ng/ml (p<0.001). Serum thyroglobulin values ≥ 5.6 ng/ml in early postoperative period was found to increase the risk of recurrence 2.38 times (p=0.002). When the thyroglobulin of the patients with postoperative antithyroglobulin positivity was excluded from the statistics of this study, the patients in the TSH ≥30 uIU/ml period with serum thyroglobulin (stimulated thyroglobulin) values ≥0.285 ng/ml had 3.087 times increased likelihood of recurrence (p<0.001). As a result, in this study; increase in tumor diameter, male sex, initial lymph node metastasis, stage III and higher stage, presence of capsule invasion, increase in the nodule size that was initially measured with ultrasonography, multinodularity, lymph node dissection along with total thyroidectomy, postoperative thyroglobulin value higher than ≥2 ng/ml and cut-off value for serum postoperative thyroglobulin higher than ≥ 5.6 ng/ml, thyroglobulin value in the TSH supressed period higher than ≥ 0.3 ng/ml, thyroglobulin value in the TSH stimulated period higher than ≥2 ng/ml and cut-off value for serum thyroglobulin value in the TSH stimulated period higher than ≥0.285 ng/ml were found to increase recurrence risk as prognostic risk factors. We recommend that these factors are kept under consideration in patient follow-up.