Analysis Of Risk Factors Of Bone Metastases From Differentiated Thyroid Cancer And The Effect Of ¹³¹Ⅰ Therapy For Its Locoregional Progression-Free Survival

Part 1 Analysis of Risk Factors of Bone Metastases from Differentiated Thyroid CancerObjectivesTo understand the risk factors for the occurrence of bone metastases in differentiated thyroid cancer(DTC),so as to target the management of patients with high risk factors,to identify and treat bone metastases as early as possible,and to improve the prognosis of patients.Materials and MethodsA retrospective analysis was performed on patients with DTC who were treated with 131Ⅰ treatment for the first time in the Department of Nuclear Medicine from January 2014 to December 2016.It was analyzed from three aspects:demographic characteristics,clinical data and pathological data.IBM SPSS Statistics 20.0 statistical software was used for analysis.The classified variables are described by frequency(percentage),and the continuous numerical variables are described by means and standard deviation.According to the situation,Pearson chi-square test,corrected chisquare test and Fisher exact probability method were used to compare whether there were differences among the factors,and then factors with statistical differences were included in binary logistic regression analysis.Bilateral tails P<0.05 was statistically significant.ResultsA total of 1451 patients were included in this study,including 27 cases(1.9%)in bone metastases group and 1422 cases(98.1%)in non-bone metastases group.Univariate analysis showed that age at diagnosis of DTC(P<0.001),sex(P<0.042),presence or absence of non-bone distant metastases(P<0.001),presence or absence of neck lymph node dissection(P<0.001),pathological types of primary tumour(P<0.001),maximum diameter of primary focus(P<0.001),presence or absence of vascular invasion or tumor thrombus(P<0.001),and presence or absence of cervical lymph node metastases(P=0.014)were statistically different in the occurrence of bone metastases.Binary logistic regression analysis showed that follicular variant of papillary thyroid carcinoma(P=0.033,OR=6.460,95%CI1.166-35.784),non-papillary carcinoma(follicular carcinoma or combined with papillary carcinoma)(P<0.001,OR=82.169,95%CI 9.260-729.154),and distant metastases to non-bone(P=0.002,OR=14.307,95%CI 2.725-75.128)were independent risk factors for bone metastases in patients with DTC.ConclusionIn this study,the incidence of bone metastases from DTC was 1.9%.Follicular variant of papillary thyroid carcinoma,non-papillary carcinoma(follicular carcinoma or combined with papillary carcinoma),and non-bone distant metastases are independent risk factors for bone metastases in DTC patients,which reminds clinicians to pay special attention to patients with follicular variant of papillary thyroid carcinoma or non-papillary carcinoma during the routine treatment and follow-up management,and to be alert to the occurrence of bone metastases while treating existing non-bone distant metastatic lesions,so as to detect,diagnose,and treat bone metastases as early as possible,extending the life expectancy of patients and improving the quality of life.Part 2 Analysis of the Effect of 131Ⅰ Therapy for Locoregional Progression-Free Survival of Bone Metastases from Differentiated Thyroid CancerObjectivesAnalyzing the control of 131Ⅰ therapy on the locoregional progression-free survival(LPFS)of bone metastatic lesions in differentiated thyroid cancer(DTC)to determine the factors affecting its eficacy and assist clinicians to formulate appropriate treatment strategies.Materials and MethodsThe medical records of 91 patients with DTC bone metastases treated by 131Ⅰ in the Department of Nuclear Medicine from January 1,2006 to December 31,2017 were reviewed.Two patients who surgically removed all the bone lesions prior to 131Ⅰ treatment and could not be analyzed for LPFS after 131Ⅰ therapy were excluded,and 89 patients were eventually enrolled.It was analyzed from three aspects:demographic characteristics,pathological data and features related to bone metastases.The LPFS survival curve of bone metastases after 131Ⅰ treatment was drawn by Kaplan-Meier method,and the median follow-up time of all patients was calculated by reverse Kaplan-Meier method.In univariate analysis,log-rank test was used to compare the differences of LPFS among groups.Cox proportional hazard regression model was used for multivariate analysis.Bilateral tails P<0.05 was statistically significant.ResultsMost of the 89 patients were female(61.8%).The main pathological type of the primary focus was follicular carcinoma(49.4%).The type of bone destruction of bone metastases in 39 patients(43.8%)was osteolytic,and 21 patients(23.6%)had both osteolytic and osteogenic changes.Most of the patients(79.8%)had bone metastatic lesions.There were 457 bone metastatic lesions,and the most common sites were pelvis(18.8%),ribs(18.6%)and thoracic vertebrae(16.8%).36 people(40.4%)had skeletal related events(SREs).The median follow-up time of all patients was 47 months(95%CI 36.220-57.780).The median follow-up time of patients with no locoregional progression was 43 months,and the longest follow-up time was 109 months(9.1 years).The median LPFS time of bone metastases after 131Ⅰ treatment was 49 months(95%CI 31.166-66.834),and the 3-and 5-year LPFS were 55.9%and 41.3%,respectively.Logrank analysis showed that bone metastasis as the first symptom or not at the diagnosis of thyroid cancer(P<0.001),presence or absence of other treatments before initial 131Ⅰ treatment for bone metastases(P<0.026),presence or absence of SREs before initial 131Ⅰ treatment for bone metastases(P<0.001),degree of 131Ⅰ uptake(P<0.001),bone mineral density changes(structural changes)(P<0.001),bone metastases with or without soft tissue masses(P<0.001)were associated with LPFS of bone metastases after 131Ⅰtreatment.Cox regression analysis showed that structural changes was an independent risk factor for LPFS in DTC bone metastases(P=0.005,HR=18.875,HR 95%CI2.439-146.056).ConclusionIn this study,patients with DTC bone metastases had a higher incidence of SREs(40.4%),reminding clinicians of the need to strengthen evaluation for early detection and treatment of the SREs.The median LPFS time of bone metastatic lesions after 131Ⅰ treatment was 49 months,and the 3-and 5-year LPFS were 55.9%and 41.3%,respectively.Bone metastasis as the first symptom at diagnosis of DTC,other treatments prior to 131Ⅰ treatment,SREs before 131Ⅰ treatment,uptake of 131Ⅰ in partial bone metastatic lesions,soft tissue masses were associated with poor LPFS of bone metastatic lesions after 131Ⅰ treatment,but they were not independent influencing factors.Bone mineral density changes(structural changes)can independently predict the poor prognosis of LPFS in bone metastases after 131Ⅰ treatment.Patients with no structural lesions but positive 131Ⅰ uptake should be actively treated with 131Ⅰ to prolong the LPFS of bone lesions and improve the prognosis.