Recurrent Thyroid Cancer Research Articles

Risk Adapted Strategies in the Management of Thyroid Cancer

There is a rising incidence of thyroid cancer world wide in the past four decades. Such a rise is observed most often in patients between the ages of 50-65. However, a majority of these newly discovered cancers are small, less than 2 cm in size, intrathyroidal papillary carcinomas. Understanding the tumor progression model of follicular cell derived cancers and appreciating the impact of prognostic factors allows the development of risk group stratification at initial diagnosis and after surgical treatment. Employing risk group stratification permits discretion in selection of surgical treatment, in the use of adjuvant therapies, and the subsequent follow up strategies. Molecular analysis of aggressive cancers opens a path to the use of targeted therapies in patients with iodine resistant recurrent or metastatic thyroid cancers. A great majority of thyroid cancer patients fall into the low and intermediate risk groups, and their long-term outcomes remain excellent. Therefore, in conclusion, understanding the biology of thyroid cancer and appreciation of prognostic factors and employing risk group stratification is crucial for cost effective treatment of cancer of the thyroid gland.

Better Quality and More Robust Instruments Are Needed for Patient-Reported Quality-of-Life Surveys in Thyroid Cancer Survivors

Better Quality and More Robust Instruments Are Needed for Patient-Reported Quality-of-Life Surveys in Thyroid Cancer Survivors

Extended Level IV Neck Dissection for Limited Prophylactic Clearance of Level V in Node-Positive Papillary Thyroid Carcinoma: a Homogenous Study Population.

There is near consensus that prophylactic lateral neck dissection has no role in the management of differentiated thyroid cancer, but the extent of lateral neck dissection in differentiated thyroid cancer remains controversial, especially whether level V should be addressed or not. There is lot of heterogeneity in reporting of the management of level V in papillary thyroid cancer. We at our Institute address the lateral neck positive papillary thyroid cancer with selective neck dissection involving levels II-IV, performing extended level IV dissection with inclusion of the triangular area delineated by the sternocleidomastoid muscle, the clavicle, and the perpendicular line drawn to the clavicle from the point where the horizontal line at the level of cricoid cuts the posterior border of sternocleidomastoid muscle. Retrospective analysis of the departmental data set related to thyroidectomy with lateral neck dissection from 2013 to mid-2019 for papillary thyroid cancer, was carried out. Patients with recurrent papillary thyroid cancer were excluded as were patients with involvement of level V. Data related to the demography of patients, histological diagnosis, and postoperative complications were compiled and summarized. Note was made of the incidence of ipsilateral neck recurrence and the neck level involved with recurrence noted. Data was analyzed for fifty-two patients of non-recurrent papillary thyroid cancer who had undergone total thyroidectomy and lateral neck dissection involving levels II-IV, with extended dissection at level IV. It should be noted that none of the patients had clinical involvement of level V. Only two patients had lateral neck recurrence, both the recurrences were in level III, one on the ipsilateral side and the other on the contralateral side. Recurrence in the central compartment was noted in two patients, with one of these patients also having ipsilateral level III recurrence. One of the patients had distal metastasis to the lungs. Transient paresis of the unilateral vocal cords was noted in seven patients which got resolved within 2months in all of them. Transient hypocalcemia was noted in four patients. Although our series has a small sample size with limited follow-up, it is one of the few studies in which prophylactic level V dissection has been studied in a homogenous study population of non-recurrent papillary thyroid cancer. Our study has shown that prophylactic dissection of level V may have a limited role, but further large multi-institutional studies need to be carried out to come up with a definite answer.

Analysis of remote results of treatment of patients with maxillary sinus cancer

Maxillary sinus cancer is one of the most complex malignancies to treat and has an unfavorable prognosis for long-term outcomes. The purpose of the study: based on the evaluation of long-term treatment outcomes (mortality, survival) to analyze the effectiveness of treatment of patients with maxillary sinus cancer and other factors which influence the outcome, including the level of expression of molecular markers. Object and methods: Long-term results of surgical treatment of 103 patients with maxillary sinus cancer stage II-IV (T2-4N0-3M0) were evaluated, which was performed in the ENT oncology department of І.І. Mechnikov Dnipropetrovsk Regional Clinical Hospital over the period of 2011-2017. Remote follow-up of patients was conducted until 2019. Results: The effectiveness of the treatment is confirmed by the analysis of survival in the studied sample: annual survival of 87.36% (95% CI 80.94-93.78); three-years’ survival – 42.75% (95% CI 33.2-52.3); five-years’ survival – 19.76% (95% CI 12.07-27.45); median survival – 32.13 (95% CI 27.0-53.0) months. Using a regression analysis of the proportional risks by Cox, it was proved that patients with recurrences of thyroid cancer die from cancer 3.13 times more often (p=0.009) than individuals in whom cancer was not accompanied by recurrence, with increasing expression of the marker TIMP-1 per unit the risk of adverse outcomes for patients is reduced by 2.56 times (p=0.034). Conclusions: Evaluation of long-term treatment outcomes (mortality, one-, three-, and five-years’ survival) of patients with maxillary sinus cancer has proven the effectiveness of treatment and approaches to their determination.

Detailed characterization of metastatic lymph nodes improves the prediction accuracy of currently used risk stratification systems in N1 stage papillary thyroid cancer.

The characteristics of metastatic lymph nodes (MLNs) have been investigated as important predictors of recurrence and progression in papillary thyroid cancer (PTC). However, clinically applicable risk stratification systems are limited to the assessment of size and number of MLNs. This study investigated the predictive value of detailed characteristics of MLNs in combination with currently used risk stratification systems. We retrospectively characterized 2811 MLNs from 9014 harvested LNs of 286 patients with N1 PTC according to the maximum diameter of MLN (MDLN), maximum diameter of metastatic focus (MDMF), ratio of both diameters (MDMFR), lymph node ratio (LNR, number of MLNs/number of total harvested LNs), presence of extranodal extension (ENE), desmoplastic reaction (DR), cystic component, and psammoma body. Factors related to the size and number of MLNs were associated with increased risk of recurrence and progression. Extensive presence of ENE (>40%) and DR (≥50%) increased the risk of recurrence/progression. The combination of MDLN, LNR, ENE, and DR had the highest predictive value among MLN characteristics. Combination of these parameters with ATA risk stratification or 1-year response to therapy improved the predictive power for recurrence/progression from a Harrell's C-index of 0.781 to 0.936 and 0.867 to 0.960, respectively. The combination of currently used risk stratification systems with detailed characterization of MLNs may improve the predictive accuracy for recurrence/progression in N1 PTC patients.

Effectiveness of Injecting Cold 5% Dextrose into Patients with Nerve Damage Symptoms during Thyroid Radiofrequency Ablation.

BackgroundAlthough radiofrequency ablation (RFA) is a safe treatment for thyroid tumors, nerve damage is a frequent complication. A previous retrospective study suggested that an injection of cold 5% dextrose in water (5% DW) can reduce nerve damage during RFA. This study validated the efficacy of injecting cold 5% DW for management of nerve damage during RFA.MethodsBetween November 2017 and December 2018, 242 patients underwent 291 RFA sessions for treatment of benign thyroid nodules or recurrent thyroid cancers. Using a standardized technique, cold (0°C to 4°C) 5% DW was immediately injected around the damaged nerve into patients with any symptoms suggesting nerve damage. The incidence of nerve damage, the volume of 5% DW injected, symptom recovery time and the incidence of permanent nerve damage were evaluated.ResultsNineteen patients experienced nerve damage symptoms related to 21 RFA sessions, including 17 patients during 19 sessions and two patients on the day after two sessions. Patients with nerve damage symptoms detected during RFA were treated by injection of a mean 41 mL (range, 3 to 260) cold 5% DW, but the two patients who experienced symptoms the next day did not receive cold 5% DW injections. Immediate recovery was observed after 15 RFA sessions in 14 patients. No patient experienced permanent nerve damage.ConclusionInjection of cold 5% DW is effective in managing nerve damage during RFA of thyroid lesions.

Re: "The De Novo Detection of Anti-Thyroglobulin Antibodies and Differentiated Thyroid Cancer Recurrence" by Yin et al.

None.

Response to Rosário and Souza Côrtes re: "The De Novo Detection of Anti-Thyroglobulin Antibodies and Differentiated Thyroid Cancer Recurrence".

Response to Rosário and Souza Côrtes re: "The De Novo Detection of Anti-Thyroglobulin Antibodies and Differentiated Thyroid Cancer Recurrence".

Disección cervical radioguiada con semillas de I125 como tratamiento de la recurrencia de cáncer papilar de tiroides

Lymph nodes are the most common place of recurrence of papillary thyroid cancer, and surgery can be considered a therapeutic option. The risks of surgery increase with every intervention. We present 3 cases of cervical non palpable thyroid cancer recurrence managed with I125 seed radioguided cervical dissection from 2017 to 2019. Two of the cases had already a thyroidectomy and central compartment lymphadenectomy performed. The seed was placed guided by US on the lesion and its position was confirmed afterwards. The target was successfully localized in 100% of cases. There was no post surgery complications. There was no evidence of recurrence with a mean follow up of 15 months. Radioguided surgery using I125 seed it is a save technique and it offers a precise localization of the non palpable thyroid cancer recurrence.

Abstract B093: Upregulated and downregulated microRNA-signatures in thyroid cancer health disparities

Abstract Filipino Americans (FA) are known to have a higher incidence, recurrence, and mortality of thyroid cancer (TC) than other Asians Americans or European Americans (EA). Understanding the molecular mechanisms that underpin the genetic defect in metabolism and their impact on thyroid cancer oncogenesis in FA are critical for addressing the health disparity. Mechanisms that link genetic defects and lifestyle factors to thyroid cancer progression have not been defined. Lifestyle and genetic variations among FA lead them to a higher risk of metabolic diseases but no study showed to elucidate the mechanism of thyroid health disparities cancer so far. Recent studies clearly demonstrate that miRNA plays an important role in carcinogenesis via targeting both oncogene and tumor suppressor gene and lifestyle changes may potentially alter miRNA signatures. Therefore, we hypothesize that miRNA expression contributes to tumor grade, prognosis, and thyroid cancer health disparities. We examined miRNA expression profiles in FA vs. EA. We analyzed miRNA-sequence (miRNA-seq) by next-generation sequencing (NGS). The pathways linked to miRNAs were analyzed by ingenuity pathway analysis (IPA) software. Correlations between disease staging to miRNA upregulation and downregulation were elucidated. Both upregulated and downregulated miRNAs were validated by quantitative real-time PCR (qPCR) using miRNA extracted from paraffin-embedded thyroid tissues. We found hundreds of upregulated and downregulated miRNA and piRNA from this study. We chose 10 miRNA down-regulated, and 10 up-regulated miRNA FA compared to EA TC patients (p<0.05). Quantitative PCR (qPCR) was done to confirm our NGS data. Differential miRNA expressions between FA vs. EA patient tumor tissues were observed with advanced staging. Evolutionarily conserved miRNA clusters, which are known to initiate malignancy, were shown to be upregulated in FATC vs. EATC. While those miRNAs are known to regulate pathways involved in cancer invasion and metastasis, they were shown to be down-regulated in FATC patients vs. EATC. The significantly top ten down-regulated/upregulated miRNA-signature suggests that it can be a diagnostic, prognostic, and predictive biomarker in TC health disparities. Citation Format: Ryan Davis, Yan C Wongworawat, Mia C Perez, Krystal Santiago, Saurav Roy, Charles Wang, Alfred A Simental, Salma Khan. Upregulated and downregulated microRNA-signatures in thyroid cancer health disparities [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr B093.

Serum Thyroglobulin Antibodies Switching from Negative to Positive Does Not Necessarily Indicate Structural Thyroid Cancer Recurrence

Serum Thyroglobulin Antibodies Switching from Negative to Positive Does Not Necessarily Indicate Structural Thyroid Cancer Recurrence

The Adoption of Ultrasound-guided Radiofrequency Ablation of Thyroid Nodules in the United States.

The Adoption of Ultrasound-guided Radiofrequency Ablation of Thyroid Nodules in the United States.

MON-436 Cribriform-morular Variant of Papillary Thyroid Carcinoma: A Case Report

Background:Cribriform - morular variant is a rare variant of papillary cancer with 1–2 % prevalence. There are no established guidelines to screen for thyroid cancer in patients with APC gene mutations and FAP. We present a case of a young female with APC gene mutation and thyroid cancer.Case:Female, 25 years-old, without anemia, underwent colonoscopy at age 22 and multiple polyps were seen. One polyp showed intramucosal carcinoma with high-grade dysplasia. She was diagnosed with FAP. She was found to have APC gene mutation on genetic analysis. No family history of FAP was reported.Chest and abdominal CT showed multiple thyroid nodules.Thyroid ultrasound showed 3 nodules. The largest is in the mid R lobe, measuring 1 cm, and is isoechoic to hypoechoic, containing some small central cystic areas. The nodules in the left lobe measure 0.6 and 0.7 cm.FNA of the right thyroid nodule showed follicular neoplasm. Afirma was suspicious.She underwent total thyroidectomy.Pathology report showed multifocal tumor in both right (0.8 cm) and left lobe (0.5 cm). Histologic type was Papillary carcinoma, cribriform - morular variant. All surgical margins were negative. No angio-lymphatic invasion or extra thyroidal extension was identified.Pathologic stage classification was m pT1a pN0 pM0.Patient did not receive RAI ablation.Patient doing well and no further recurrence of thyroid cancer is noted.Discussion:Patients with FAP have a greatly increased risk for colorectal cancer and also have an elevated risk for other cancers including thyroid cancer (1%-2% compared to 1% in general population). According to ACG guidelines of 2015, annual thyroid screening by ultrasound should be recommended to individuals affected with FAP. Additionally, thyroid cancer found in unscreened patients with FAP was more advanced as compared to patients screened for cancer requiring less aggressive approaches. On ultrasonography, most nodules had benign-looking features (well-defined, hypoechoic, oval to round shapes without calcification), but some nodules had capsular invasion and larger height: width shape. In preoperative FNA, they were diagnosed as CMV-PTC/PTC but could also present as follicular neoplasm or PTC-follicular variant. Compared to conventional PTC, CMV-PTC had a lower frequency of lymph node metastases at presentation (12%) and distant metastases (3%) as well as lower recurrence rates (8.5%) and patient mortality rates (2%). Physical exam and clinical history is not sufficient to screen for cancer.In patients with APC gene mutations and FAP, there should be high suspicion for diagnosing thyroid cancer as the nodules are usually benign looking and small in size. As noted in the case, nodules were found incidentally, and tumor size was small with benign looking nodules. Additionally, screening should be focused more on young females below the age of 35 because of the high prevalence of cancer.

MON-507 A Descriptive Study of Clinical and Surgical Characteristics of Patients with Thyroid Cancer: A 10-Year Retrospective Study from UAE

Introduction: Thyroid cancer is the sixth most common type of cancer in the UAE. It has been observed that the incidence of thyroid cancer has been steadily increasing worldwide. However, limited studies about thyroid cancer has been reported from the Arab gulf region.Objective: The objective of this study was to describe the clinical and surgical characteristics of patients with thyroid cancer in the UAE population.Methods: Retrospective analysis was performed on all adult patients attending thyroid cancer clinic at Sheikh Khalifa Medical City (SKMC) in Abu Dhabi, UAE over ten years from 2008 to 2018. All patients with a confirmed histological diagnosis of thyroid cancer who had surgical intervention with long-term follow up data on cancer outcome have been included. Categorical variable analysis and descriptive analysis were used to identify factors associated with increased risk of developing thyroid cancer.Results: Total number of 203 patients with confirmed diagnosis of thyroid cancer were included. Most of the patients were female (72.9 %, n=148). Mean age at the time of diagnosis was 40±13 years. Papillary thyroid carcinoma was the most common thyroid cancer observed (95.6%, n=194) followed by follicular thyroid carcinoma (2%), medullary thyroid carcinoma (1.5%) and mixed medullary-papillary (0.9%). Classical variant and follicular variant of papillary thyroid carcinoma were the two most commonly observed histological subtypes of thyroid cancer with prevalence of 54.7 % and 21.7 % respectively. 91.1% (n=185) of patients had total thyroidectomy and 8.9%(n=18) had hemithyroidectomy. Female gender has been observed to be associated with higher prevalence of thyroid cancer (OR 2.78, 95% CI 1.18–4.50, p=0.001). Smoking status did not show any significant association with developing thyroid cancer. Recurrent thyroid cancer was observed in 9.4%(n=19). Most of recurrence happened as local metastasis 89.5%(n=17). The mean time of recurrence was 24 months (range, 7–64 months).Conclusions: Our data demonstrate that in the UAE population, papillary thyroid cancer is the most common type of thyroid cancer. Female gender is observed to be associated with higher risk of thyroid cancer. Recurrence rate of thyroid cancer noted to be 9.4%. Further studies are required to investigate factors associated with recurrence and cancer free survival rates.

MON-448 Detection of Thyroid Cancer Recurrence in Patients with Positive Thyroglobulin Antibody Receiving Immunoglobulin Therapy

Introduction: Differentiated thyroid cancers such as papillary and follicular thyroid cancer make up more than 90% of all thyroid cancers. The presence of thyroglobulin autoantibodies makes interpretation of the thyroglobulin level unreliable, as it could be falsely low or falsely high. Studies have shown that rising thyroglobulin antibody levels, could be used to monitor for disease recurrence in patients with negative thyroglobulin and imaging studies. However, there are challenges in detecting recurrence in patients with normal thyroglobulin level and thyroid imaging studies, who are on lifelong immunoglobulin therapy and who have increasing thyroglobulin antibody levels.Clinical case: A 63 yr old female was found to have an incidental left thyroid nodule at age 48yrs from a carotid ultrasound. She underwent US guided FNA of the thyroid nodule and was found to have papillary thyroid cancer. She had total thyroidectomy a month later, with removal of a 1.4cm primary, with no evidence of extrathyroidal extension, clear margins and no evidence of lymphovascular invasion – Stage T1bN0M0. There was left level 6 neck dissection with no carcinoma identified in the 2 lymph nodes removed. She received 105.3 mCi radioactive iodine (RAI) and whole body thyroid scan done 7 days later revealed, increased uptake involving the thyroid bed likely residual thyroid tissue. Activity was noted inferolateral to the right thyroid bed which most likely represents a lymph node. There was no evidence of distant metastasis.She was commenced on levothyroxine post operatively. Her other past medical history is significant for idiopathic urticaria and angioedema, immune deficiency disorder with low IgG and IgM and asthma. She was commenced on monthly IV immunoglobulins 5yrs post RAI therapy, due to recurrent sinusitis, rhinitis and chronic diarrhea. She was later transitioned to weekly SQ immune globulin – Hizentra which she is on till date.Over the past 15 years, serial neck ultrasounds post radioiodine ablation have been negative for recurrence. Her TSH ranged 14.91 to 0.04 (ref 0.27-4.2 uiu/ml) and thyroglobulin (Tg) titer remains <0.1 (ref <0.1). Her thyroglobulin antibody titers have trended up from <0.2 (ref <2.0) 5yrs post RAI therapy to 49 (ref <4 iu/ml)) on her most recent test this year. She is currently undergoing further work up to rule out recurrence of her cancer. In our review of the literature we found one report that showed use of Liquid Chromatography–Mass Spectrometry (LC-MS) was able to differentiate thyroid cancer recurrence in an individual with positive antithyroglobulin antibody receiving immunoglobulin therapy.Conclusion: In patients with negative Tg levels, but elevated thyroglobulin antibody while receiving immune globulin therapy, thyroglobulin antibody levels may not be a reliable indicator of thyroid cancer recurrence. Measurement of Tg levels using a LC-MS may provide some clarity.

The De Novo Detection of Anti-Thyroglobulin Antibodies and Differentiated Thyroid Cancer Recurrence.

Background: The prevalence and clinical significance of de novo detection of anti-thyroglobulin antibodies (TgAbs) during the follow-up of patients with differentiated thyroid cancer (DTC) is unknown. Methods: We utilized the National Thyroid Cancer Treatment Cooperative Study registry (1987-2012). Patients registered after 1996 (n = 3318) were analyzed. We identified 1545 subjects who had available TgAb status (TgAb cohort) between years 1996 and 2012, of whom 1325 were TgAb negative at first postoperative follow-up testing. From this initial TgAb-negative group, we excluded 513 patients: 423 patients who had less than 3 years of follow-up and/or fewer than three follow-up visits, 86 patients with persistent disease after initial treatment, and 4 patients with data entry errors. The remaining 812 patients were included for analysis, comprising the TgAb persistently negative group (defined as TgAb negative for at least 3 consecutive follow-up visits and at least 3 years of follow-up) (n = 772) and the de novo TgAb-positive group in whom TgAbs became detectable (n = 40). We then assessed whether de novo appearance of TgAb was associated with DTC structural recurrence by using the Kaplan-Meier method. Results: The de novo detection of TgAb occurred in 5% of DTC patients. Recurrence of DTC in the TgAb persistently negative group compared with the de novo TgAb-positive group did not differ significantly (9.6% vs. 15.0%, p = 0.23). Baseline characteristics, histology, history of radiation exposure, staging, and median duration of follow-up were similar between the two groups. Interestingly, in all six patients who suffered a recurrence in the de novo TgAb-positive group, the TgAbs were negative at the time of recurrence detection and became positive at a median of 2.1 (0.7-8.7) years after the structural recurrence. Conclusions: Utilizing a large North American DTC registry, we found the prevalence of de novo TgAb detection to be 5% among initially TgAb-negative patients. We did not find a statistically significant association between de novo TgAb development and DTC structural recurrence. Larger prospective studies are required to confirm these findings and further assess the significance of de novo TgAb detection in the follow-up of DTC.

Abstract #799784: Development of Thyroid Associated Orbitopathy After Thyroidectomy for Recurrent Papillary Thyroid Cancer

Abstract #799784: Development of Thyroid Associated Orbitopathy After Thyroidectomy for Recurrent Papillary Thyroid Cancer

Localización con semillas radioactivas 125I (RSL) en cirugía de metástasis cervical de cáncer de tiroides

IntroductionThe aim of this work is the evaluation of usefulness of radioactive seed localization (RSL) for the detection of cervical recurrence of thyroid cancer in order to improve the surgical outcome. Material and methodTen patients with thyroid cancer and lymph node involvement (4 naive and 6 with cervical recurrence) evidenced by ultrasound, cytology/Tg-FNAB (reoperated group) were selected for this procedure. A 125I seed was placed in the metastatic lesion using a needle guided by ultrasound. During surgery, a handheld gamma probe/portable gammacamera were used for lesion localization and excision. After removing the target tissue, it was verified that the seed was included in the excised tissue. Surgical intervention duration, lesion location, seed activity, thyroglobulin level, effective radiation dose, complications and the degree of surgical resection were analyzed. ResultsAll the marked nodes were positive in histology. The mean duration of the ultrasound procedure was 11.4±3.4minutes. Seed was kept inside the patient, in average, during 4days (1-7) and the average surgical time was 44.7±29.1minutes. We found 21 metastatic specimens with an average diameter 13.9±6.3mm. The mean activity of the implanted seed was 71.27±21.6MBq (42.8-105) In the reoperated group, thyroglobulin level was 2.08±1.56ng/dl and decreased after surgery to 0.13±0.12ng/dl, P<.01. Only one case of transient hypoparathyroidism was found in the total group. ConclusionsThe introduction of RSL in our unit has shown benefits for the patient and medical team, being a safe and effective procedure that also improves surgical programming.

BRAFV600E Mutation is Associated with an Increased Risk of Papillary Thyroid Cancer Recurrence.

Papillary thyroid carcinoma is the most common endocrine malignancy and one of the most common cancers worldwide. However, the optimal timing and frequency of surveillance to assess for recurrence remain undetermined. As the incidence of thyroid cancer continues to rise worldwide, identifying risk factors for recurrence and investigating intervals and durations of surveillance are paramount to adapt treatment and follow-up plans to high-risk individuals and to reduce interventions for low-risk patients. Our dataset included an unselected cohort of papillary thyroid carcinoma (PTC) patients who underwent a total thyroidectomy (or unilateral then completion thyroidectomy) at a single institution from 2000 to 2007. BRAF genotyping was performed on available specimens by a validated PCR-based assay. Pathologic structural recurrence was the primary outcome. We performed univariate and multivariable analyses to identify predictors of cancer recurrence. In total, 599 patients underwent complete resection of the thyroid gland for PTC. The cohort was young (mean age 45.0years), predominately female (n = 462, 76.9%), and median follow-up was 10.3years (IQR 5.4-12.2). Recurrence occurred more commonly in the BRAFV600E group (18.6 vs. 9.9%, p = 0.02). BRAF independently predicted PTC recurrence (HR 2.81, p = 0.006). BRAF mutation is an independent predictor of papillary thyroid carcinoma long-term recurrence. Understanding molecular characteristics of individual thyroid cancers may help risk-stratify patients and direct them toward more appropriate initial care and long-term surveillance strategies.

Distinguishing Recurrent Thyroid Cancer from Residual Nonmalignant Thyroid Tissue Using Multiphasic Multidetector CT

During thyroidectomy incomplete resection of the thyroid gland may occur. This complicates the imaging surveillance of these patients as residual thyroid needs to be distinguished from local recurrence. Therefore, the purpose of this study was to determine if multiphasic multi-detector computed tomography (4D-MDCT) can differentiate residual nonmalignant thyroid tissue and recurrent thyroid carcinoma after thyroidectomy. In this retrospective study, Hounsfield unit values on multiphasic multidetector CT in precontrast, arterial (25 seconds), venous (55 seconds), and delayed (85 seconds) phases were compared in 29 lesions of recurrent thyroid cancer, 29 with normal thyroid, and 29 with diseased thyroid (thyroiditis/multinodular thyroid). The comparison of Hounsfield unit values among lesion types by phase was performed using ANOVA. The performance of Hounsfield unit values to predict recurrence was evaluated by logistic regression and receiver operating characteristic analysis. All 3 tissue types had near-parallel enhancement characteristics, with a wash-in-washout pattern. Statistically different Hounsfield unit density was noted between the recurrence (lowest Hounsfield unit), diseased (intermediate Hounsfield unit), and normal (highest Hounsfield unit) thyroid groups throughout all 4 phases (P < .001 for each group and in each phase). Dichotomized recurrence-versus-diseased/normal thyroid tissue with univariate logistic regression analysis demonstrated that the area under the receiver operating characteristic curve for differentiating benign from malignant thyroid for the various phases of enhancement was greatest in the precontrast phase at 0.983 (95% CI, 0.954-1), with a cutoff value of ≤62 (sensitivity/specificity, 0.966/0.983) followed by the arterial phase. Recurrent thyroid carcinoma can be distinguished from residual nonmalignant thyroid tissue using multiphasic multidetector CT with high accuracy. The maximum information for discrimination is in the precontrast images, then the arterial phase. An optimal clinical protocol could be built from any number of phases but should include a precontrast phase.