Clinical Features of Pediatric Papillary Thyroid Cancer Patients in Southern China

Objectives: ackground Thyroid cancer is rare in children and adolescents. Compared with thyroid cancer in adults, it exhibits differences in pathophysiology, clinical features, and outcomes. So we should pay more attention to the study of pediatric thyroid cancer especially of PTC (papillary carcinoma) which accounts for more than 90% of pediatric thyroid cancer to manage a unique treatment guidelines. Methods We retrospectively investigated 80 pediatric PTC patients (20 males and 60 females) who were under 22 when they were treated from 2012 to 2017 (mean age = 16.4±4.1 years) in our institute, only 78 of them had accepted our follow-ups (follow-up = 2.0±1.2 years). 4.2 ± 7.2months(range,0.5-59.4 months)after surgery, all the patients performed ¹³¹I remnant ablation treatment using 134.0 ± 40.7mci(range,30-200mci)of ¹³¹I. Result There are 12 patients(15.0%)diagnosed as PTC subtypes. Only 2 patient did not find cervical lymph nodes metastasis nor distant metastasis, while 78 patients(97.5%) were with cervical lymph nodes metastasis and 15 patients(18.75%)with lung metastasis. Only 62 patients measured thyroglobulin (TG) and TG antibodies before the first ¹³¹I remnant ablation treatment on the same day as the ¹³¹I ablation treatment. TG antibodies are positive in 21 patients and negative in 41 patients. Among them which TG antibodies are negative, TG is < 2μg/l in 6 patients(14.63%), and ≥10μg/l in 29 patients(70.73%). In the rest 6 patients the TG levels are more than or equal to 2μg/l but less than 10μg/l(14.63%). In addition, 3 patients just measured TG antibodies which are negative. The number of iodine treatment courses was about 1.9 ±1.0 times(range,1-5times),and the cumulative ¹³¹I activity was about 295.2 ± 187.4mci(range,40-826mci). In the 78 patients, only 14 patients(17.95%) of them have achieved Excellent response, 6 patients(7.69%) of them are Biochemical incomplete response, 49 patients(62.82%) of them are Structural incomplete response, 9 patients(11.54%) of them are Indeterminate response according to 2015 American Thyroid Association Management Guidelines. No patient died during follow-up. Patients with lung metastases are more likely to be biochemical incomplete response (P=0.022) or structural incomplete response (P=0.031). The larger the metastatic foci of cervical lymph nodes, the more likely the patients to be structural incomplete response(P=0.049).There is no significant correlation between the maximum diameter of metastatic cervical lymph nodes and the incidence of structural incomplete response(P>0.05). Conclusions This study describes the clinical features and short-term prognosis of pediatric PTC patients in southern China. Compared with adult PTC, subtypes may be more common in pediatric PTC patients. Cervical lymph node metastasis and lung metastasis are more common in them, too. The short-term prognosis is not as good as expected. Pulmonary metastasis and large metastatic foci of cervical lymph nodes are important poor prognostic factors for pediatric PTC.