Clinical Analysis Of Papillary Thyroid Carcinoma In Children And Adolescents

Research background and purposeThyroid cancer（TC）is a rare disease of children and adolescents,accounting for about 1.4%of all childhood malignant tumors,but it ranks first among endocrine malignant tumors in children and adolescents.In recent years,with the increase of its incidence,there are more attention has been paid on thyroid cancer of children and adolescents gradually.There are mainly included papillary thyroid carcinoma（PTC）,follicular thyroid carcinoma（FTC）,medullary thyroid carcinoma（MTC）and anaplastic thyroid carcinoma（anaplastic thyroid carcinoma,ATC）of thyroid cancers in children and adolescents.Among the four dominant pathological types of thyroid carcinoma,papillary thyroid carcinoma is the most frequent one,accounting for more than 90%,and the next is follicular thyroid carcinoma,medullary thyroid carcinoma and anaplastic thyroid carcinoma are extremely rare.Children and adolescents are not a reduced version of adults,and their clinicopathological features,disease course,management strategies,and prognosis are quite different from adults.At present,there is no domestic guideline about the specific treatment methods for children and adolescents with thyroid cancer,and the treatment methods recommended by relevant foreign guidelines are relatively general.The treatment strategies,including whether to perform postoperative I¹³¹ treatment and its dose,and the choice of cervical lymph node dissection,which are directly calculated with reference to adult data.It is unclear whether prepubertal patients（<10-15 years old）have a greater tumor burden,and whether children and adolescents are at greater risk of papillary thyroid carcinoma disease recurrence,the 2015 American Thyroid Association（ATA）guidelines recommended treating"prepubertal"studies with"pubertal/post-pubertal"patients to learn more about the potential impact of pubertal development on disease incidence and biology.To sum up,given that the incidence of papillary thyroid carcinoma of children and adolescents is much lower than that in adults,there is a lack of relevant evidence to guide their individualized clinical diagnosis and treatment.The existing guidelines that can guide their treatment are mostly derived from adult-related guidelines in a brief way.This study retrospectively analyzed the clinical data and follow-up data of children and adolescents with PTC in a single center in the past 15 years,explored the clinical characteristics,treated metastasis,prognosis and other characteristics of children and adolescents with PTC,and evaluated the clinical characteristics and long-term prognosis of children and adolescents with PTC before and after adolescence according to age groups.Materials and Methods:A retrospective study was performed on patients with papillary thyroid carcinoma aged≤19 years who completed initial surgical treatment at the Head and Neck Surgery Center of Sichuan Cancer Hospital from September 2006 to August 2020.Their demographic information,tumor characteristics information was obtained by reviewing medical records,and their follow-up information were obtained by telephone follow-up or by reviewing outpatient visits.According to the consensus of Chinese expert on thyroid nodules and differentiated thyroid cancer,children were defined by the age of 14as the standard for pre-puberty,and they were divided into two groups:the<14-year-old group and the≥14-year-old group.SPSS software was used to analyze their demographics,characteristics,clinicopathological findings of tumors,surgical methods,and prognostic outcomes.Result:1.A total of 84 patients with PTC were enrolled in this analysis.The age ranged from 6 to 19 years,with a mean age of 15.8±3.5 years old at diagnosis of PTC,Twenty-one（25%）were males and 63（75%）were females;mean age at menarche of female patients was 12.6±1.0 years old;mean age of maternal at given birth was 25.6±4.0 years old;twenty-nine（34.5%）were thyroid cancer combined with Hashimoto thyroiditis;Patients were divided into two groups according to age:≤12（19ceses）and>12 years old（65ceses）.The extrathyroidal extension rate was 64.3%,the cervical lymph node metastasis rate was 85.7%,the central neck lymph node metastasis rate was 84.5%,the lateral neck lymph node metastasis rate was 67.9%,and the distant metastasis rate was6%;Total thyroidectomy was performed in 50 patients and 34 without total thyroidectomy.The incidence of postoperative hypocalcemia was 42.9%,of which 2patients showed permanent hypoparathyroidism,and the recurrent laryngeal nerve injury rate was 12.3%;Eighty-four patients were followed up for 8-182 months,respectively,with a median follow-up time of 127 months.A total of 9 patients were lost to follow-up,with a lost follow-up rate of 89.3%,and 14 patients（16.7%）had recurrence or disease progress.The recurrence rate was higher in the<14 year old group than in the>14 year old group after non-total thyroidectomy（57.1%vs7.4%,p=0.01）.As of the last follow-up time,except for 9 patients who were lost to follow-up,all patients were alive,and the 5-year progression-free survival（PFS）rates were 89.3%.2.Compared with the≥14y group,The rate of patients with second or more children in birth order was higher,(52.6%2^nd+vs 25.9%2^nd+,p=0.032),and the rate of lateral neck lymph node metastasis was also higher（94.7%vs 60%,p=0.032）.The male-to-female ratio（7:12 vs 14:51,p=0.175）,age of menarche of female patients（12.3±1.0 vs 12.7±1.0,p=0.464）,maternal age at given birth（27.7±5.9 vs25.0±3.2,p=0.099）,primary symptom（p=0.099）,tumor size（2.8±1.8cm vs 2.5±1.4cm,p=0.517）,mutifocality（42.1%vs 32.3%,p=0.584）,lung metastasis（6.0%vs 4.6%,p=0.316）,extrathyroidal extension（p=0.714）,distribution of pathological types（p=0.081）were all no significant difference.During the follow-up period,except 9patients who were lost to follow-up,all patients in the two groups survived.After the first treatment,6 patients（31.6%）in the<14years group had recurrence or disease progress,and 8 patients（12.3%）in the≥14years group had recurrence or disease progress.However,there was no significant difference in the rate of progression-free survival（PFS）between the two groups.There was also no significant difference in PFS according to surgical treatment,extrathyroidal extension,lymph node metastasis and I¹³¹ treatment.Conclusion:A total of 84 children and adolescents with PTC aged≤19 years were included in this study for analysis.It was discovered that they had the characteristics of large primary tumor diameter,multifocal growth,advanced aggressiveness,high lymph node metastasis rate and relatively good prognosis.Compared with patients aged≥14 years,patients aged<14 years had a higher rate of lateral cervical lymph node metastasis and higher birth order,but there was no significant difference in PFS between the two groups.After non-total thyroidectomy,the recurrence rate of children<14 years old was higher（57.1%vs 7.4%,p=0.01）,suggesting total thyroidectomy for younger children.Whether or not total thyroidectomy,lateral cervical lymph node metastasis,extrathyroidal extension and postoperative I¹³¹ treatment did not affect the PFS of children and adolescents.