Clinical Study On The Clinicopathological Features And Treatment Strategies Of Thyroid Cancer

Purpose.The institutional database of the Thyroid Surgery Division in China-Japan Union Hospital of Jilin University was queried to audit time trend patterns in thyroid cancer(TC)management between 2008 and 2017.Methods.Retrospective longitudinal analysis.The analysis included 15,000 patients underwent primary surgery with TCs and complete information for this study.Clinicopathological features and treatment strategies were analyzed.Frequencies and multivariate tests were used to detect correlations.Logistic regression models and multiple linear regression models were used to investigate the risk factors for lymph node metastasis.Results.(1)Ten-year trends of gender and age From 2008 to 2017,trends for treated TC patients(i.e.,number of TC patients / number of surgical patients with various thyroid diseases)significantly increased per year and reached peak(> 90%)in the past three years.A total of 11,805 patients were female(78.7%),with a male to female ratio of 1: 3.69.By comparing the age distribution of patients each year,the proportion of young patients in different diagnostic years was higher than that of children,middle-aged and elderly group,reaching 59.7% in 2014.(2)Ten-year trends of histopathology Papillary was the most common histological subtype(n=14,916,99%),and the median MTD was 0.6(0.01-6.5)cm.The most common location of TC was the right side(n=5,731,38.2%),followed by the left lobe(n=5,012,33.4%),bilaterally(n=4,100,27.3%),and the isthmus(n=153,1.0%).Patients with multifocality accounted for 40.4% and the incidence of extrathyroidal extension(ETE)was 13.5%.95.9% of TC patients were in TNM stage I,and 58.9% were in the low risk group.Incidence of ETE increased from 2.6% to 19.3% over time.TC multifocality increased from 26.4% to 43.1%.There were no significant changes in the remaining pathological features.The overall incidence of lymph node metastasis(LNM)was 42.2%,central LNM(CLNM)was 24.7%,and lateral LNM(lateral LNM)was 17.5%.Comparing the clinicopathological features,we found that male,increased tumor size,multifocality,and thyroiditis increased the risk of stage N1 b disease(P < 0.05).Sex,multifocality,capsular infiltration,and tumor size were associated with the size of the metastatic LNs(P < 0.05).Sex,capsular infiltration,and nodular goiter were associated with the lymph node radio(LNR)(P < 0.05).Female sex,tumor located in inferior lobe,andmaximal tumor diameter(MTD)< 1cm,and nodular goiter were independent predictors for skip metastases(P < 0.05).(3)Trends in the treatment of TC Trends in the extent of thyroidectomy.In total,most patients underwent TT(n=7,844,52.3%),followed by lobectomy + isthmusectomy(n=4,249,28.3%),near-total thyroidectomy(n=2,527,16.8%),subtotal thyroidectomy(n=320,2%),and nodulectomy(n=64,0.4%).Before 2012 Chinese guidelines published(from 2008 to 2012),the most common surgery was near-total thyroidectomy(n=2,045,60.3%),followed by TT(n=989,29.1%),lobectomy + isthmusectomy(n=232,6.8%),subtotal thyroidectomy(n=90,2.6%).After 2012 Chinese guidelines published(from 2013 to 2015),the rate of near-total thyroidectomy decreased to 6.4%,while the rate of TT increased to 67.9%,the rate of lobectomy + isthmusectomy increased to 24.7%.Since 2015 ATA guidelines published(from 2016 to 2017),the rate of near-total thyroidectomy decreased to 1.5%,the rate of TT decreased to 48.6%,and the rate of lobectomy + isthmusectomy increased to 46.2%.Trends in LNDs.Lymph node dissections(LNDs)can be divided into five groups as follows,thyroidectomy without LND,central LND(CLND),CLND and lateral LND(LLND),and only LLND without CLND.Before 2012 Chinese guidelines published(from 2008 to 2012),the most common surgery was CLND + LLND(n=2,420,71.3%),followed by CLND(n=532,15.7%),thyroidectomy without LND(n=243,7.2%),LLND without CLND(n=198,5.8%).After 2012 Chinese guidelines published(from 2013 to 2015),the rate of CLND increased to 58.7%,while the rate of CLND + LLND decreased to 40.6%,the rate of thyroidectomy without LND and LLND without CLND had dropped to close to 0.Since 2015 ATA guidelines published(from 2016 to 2017),the rate of CLND increased to 86.4%,however,the rate of CLND + LLND decreased to 13.3%.Trend in RAI.Of the 10,273 adults(>18 years)who underwent near-total or total thyroidectomy,2,870(27.6%)patients received RAI.The RAI therapy feature showed a stable trend in 2008-2012(range from 5.5% to 12%),and increased from 12.3% in 2012 to 41.3% in 2015 while decreased to 32.4% in 2017.Trends of the percentage of patients undergoing RAI therapy in different risk groups were as follows: The percentage of RAI therapy in the low-risk group was low,ranging from 2.6 to 13.2%.RAI therapy in the intermediate-risk group increased from 6.6% in 2008 to 26% in 2011,remained stable in 2011-2012,increased to 68% in 2015,and decreased to 52.0% in 2017.RAI therapy in the high-risk group showed an overall increasing trend during the period 2008-2015 and decreased until 2017(71.2%).Conclusion.1.In summary,a threefold increase of thyroid operations for TC throughout the study period.The possible reasons are as followed.First,the incidence of TC has been steadily increasing in the past three decades in many countries and regions worldwide.Second,the rate of thyroid cancer screening in China showed a significant increase.Finally,the introduction of FNA in our center also resulted in the above growth of TC.2.In our center,TC was most common in female youth(19-44 years).Stage I and low-risk patients of PTCs were prevalent throughout the 10-year period.3.The LN characteristics of stage N1 a and N1 b disease were associated with significantly different features.Male sex,tumor size,multifocality,and capsular infiltration were independent risk factors with significant odds ratios.4.Female sex,advanced age,inferior lobe of the thyroid,and MTD < 1cm were positively associated with the incidence of skip metastases,while capsular infiltration was negatively associated with skip metastases in multivariate analysis.5.The surgical management of TC patients has undergone continuous changes over the past 10 years.This change seems to be associated with a change in the surgical approach regarding what constitutes adequate TC guideline adherence.Additionally,we found that the treatment strategy in our institution was adjusted according to the features of the contralateral lobe of cancer foci,which reflects the standardization and specificity of TC treatment.Our findings also indicate that evidence-based,multidisciplinary guidelines that address issues of clinical controversy can effectively accelerate changes in clinical practice and reduce overtreatment in TC care.