Secular trends in the prognostic factors for papillary thyroid cancer

Extrathyroidal extension and cervical node infiltration are associated with recurrences and shorter recurrence-free survival in differentiated thyroid cancer: a cohort study

Background

Differentiated thyroid cancer has excellent overall survival. However, around 20% of patients experience recurrent diseases after a certain time of follow-up. Therefore, identification of risk factors for recurrence is necessary to adjust treatment and surveillance planning.

Methods

A retrospective study was conducted of 312 patients with differentiated thyroid cancer who received surgery with and without adjuvant treatment. Clinical and pathological risk factors were analyzed for recurrences.

Results

After median follow-up of 57 months, 109 of 312 patients (34.9%) developed recurrences. Extrathyroidal extension and positive cervical nodes were significantly associated with recurrences (OR = 2.449, 95%CI:1.260–4.760, P = 0.008 and OR = 3.511, 95%CI:1.860–6.626, P < 0.001; respectively). Lympho-vascular invasion (LVI) and tumor multifocality were also associated with increased risk of recurrence (OR = 2.577, 95%CI:1.380–4.812, P = 0.003 and OR = 1.602, 95%CI:1.001–2.495, P = 0.050; respectively). Using multivariable regression, only older age and tumor infiltration to the lymph nodes were significantly associated with recurrences (OR = 2.227, 95%CI:1.037–4.782, P = 0.040 and OR = 2.966, 95%CI:1.470–5.986, P = 0.002; respectively). In addition, T4, cervical lymph node infiltration, older age, and LVI were associated with shorter recurrence-free survival.

Conclusion

Recurrence rates in our study population are relatively high. Extrathyroidal extension, positive neck lymph node, and older age were associated with recurrence risks of well differentiated thyroid cancers.

Clinical Factors Predictive of Lymph Node Metastasis in Thyroid Cancer Patients: A Multivariate Analysis

BACKGROUND

Early-stage thyroid cancers have excellent survival. However, lymph node metastases (LNM) confer a worse prognosis and are not always known preoperatively. Therefore, investigation on the clinical and histological factors predictive of LNM in thyroid cancers was conducted to tailor the extent of surgery and radioactive iodine therapy.

STUDY DESIGN

Multivariate logistic regressions were performed based on retrospective data from thyroid cancer patients seen between 2013 and 2020 at a single institution.

RESULTS

Among 913 patients, mean age was 49.4 years, 76.5% were female, 58.3% were White, 21.2% were Black, and 27.9% had LNM. In the multivariate analyses in which the outcome was LNM, White (odds ratio [OR] 1.74, 95% CI 0.98 to 3.15, p = 0.064) and Hispanic patients (OR 2.36, 95% CI 0.97 to 5.77, p = 0.059) trended toward higher risk of LNM compared to Black patients, whereas age (OR 0.98, 95% CI 0.97 to 1.00, p = 0.008) showed protective effect. Tumor size (OR 1.04, 95% CI 1.01 to 1.07, p = 0.007), extrathyroidal extension (OR 2.46, 95% CI 1.53 to 3.97, p < 0.001), lymphovascular invasion (OR 6.30, 95% CI 3.68 to 11.14, p < 0.001), and multifocality (OR 1.47, 95% CI 1.01 to 2.12, p = 0.042) were associated with higher risk of LNM. In another model with outcome as >5 LNM, tumor size (OR 1.07, 95% CI 1.03 to 1.11, p = 0.001), age (OR 0.95, 95% CI 0.93 to 0.97, p < 0.001), extrathyroidal extension (OR 3.20, 95% CI 1.83 to 5.61, p < 0.001), and lymphovascular invasion (OR 6.82, 95% CI 3.87 to 12.17, p < 0.001) remained significant predictors.

CONCLUSION

Our analyses demonstrated and confirmed that age, tumor size, extrathyroidal extension, and lymphovascular invasion are independent predictors of significant LNM, thereby conferring higher risk of recurrence. Risk of LNM based on these patient characteristics should be considered when planning an operative approach.

Papillary Thyroid Cancer Prognosis: An Evolving Field

Simple Summary

Over the last couple of decades, the prognostic stratification systems of differentiated thyroid cancer (DTC) patients have been revised several times in an attempt to achieve a tailored clinical management reflecting the single patients’ needs. Such revisions are likely to continue in the near future, since the prognostic value of a number of promising clinicopathological features and new molecular biomarkers are being evaluated. Here, we will review the current staging systems of thyroid cancer patients and discuss the most relevant clinicopathological parameters and new molecular markers that are potentially capable of refining the prognosis.

Abstract

Over the last few years, a great advance has been made in the comprehension of the molecular pathogenesis underlying thyroid cancer progression, particularly for the papillary thyroid cancer (PTC), which represents the most common thyroid malignancy. Putative cancer driver mutations have been identified in more than 98% of PTC, and a new PTC classification into molecular subtypes has been proposed in order to resolve clinical uncertainties still present in the clinical management of patients. Additionally, the prognostic stratification systems have been profoundly modified over the last decade, with a view to refine patients’ staging and being able to choose a clinical approach tailored on single patient’s needs. Here, we will briefly discuss the recent changes in the clinical management of thyroid nodules, and review the current staging systems of thyroid cancer patients by analyzing promising clinicopathological features (i.e., gender, thyroid auto-immunity, multifocality, PTC histological variants, and vascular invasion) as well as new molecular markers (i.e., BRAF/TERT promoter mutations, miRNAs, and components of the plasminogen activating system) potentially capable of ameliorating the prognosis of PTC patients.

Male sex is not an independent risk factor for recurrence of differentiated thyroid cancer: a propensity score-matching study

Male patients have a significantly higher prevalence of advanced-stage thyroid cancer. However, sex differences in the risk of differentiated thyroid carcinoma (DTC) recurrence have not been fully elucidated. Therefore, the present study aimed to investigate male sex as a prognostic factor for DTC. We assessed 5566 patients with DTC who underwent thyroid surgery between January 2009 and December 2015 at Seoul St. Mary’s Hospital (Seoul, Korea). Clinicopathological characteristics and long-term oncologic outcomes between female and male patients with DTC were compared using propensity score matching to reduce selection bias. The mean follow-up duration was 99.9 ± 18.7 months. The recurrence rate was significantly higher in male patients than female patients before matching (3.3% vs. 2.2%, p = 0.030), and there was no significant difference in recurrence rates between the matched groups after matching (3.0% vs. 2.5%, p = 0.591). Based on Kaplan–Meier analysis, the two groups did not significantly differ in disease-free survival after matching. Multivariate analysis revealed that male sex was not an independent prognostic factor of DTC recurrence. Male sex did not have a significant effect on DTC recurrence. Further studies with larger cohorts are required to validate the findings of this study.

Trends in Pediatric Thyroid Cancer Incidence, Treatment, and Clinical Course in Korea During 2004-2016: A Nationwide Population-Based Study

Background: The incidence of thyroid cancer has increased worldwide. We investigated nationwide trends in the incidence and treatment course of pediatric thyroid cancer in South Korea. Methods: Using the National Health Information Database, we analyzed 1580 patients (324 males) <20 years of age diagnosed with thyroid cancer during 2004-2016 in South Korea. The annual percentage change (APC) in the age-standardized incidence rate (ASR) was calculated by joinpoint regression analysis. The initial treatment modality was categorized as either surgery only or surgery with radioactive-iodine treatment (surgery+RAIT), and we defined new treatment events as reoperations or additional RAITs among 1464 patients followed up for ≥12 months. Results: During 2004-2016, the mean ASR per 100,000 person-years increased from 0.6 [confidence interval; CI 0.5-0.8] to 0.9 [CI 0.8-1.1], with a mean APC of 4.0% [CI 1.8-6.2]. The ASRs (APCs) among 0-9-, 10-14-, 15-17-, and 18-19-year olds were 0.07 (9.9% [CI 0.08-20.7]), 0.6 (4.6% [CI 0.2-9.2]), 2.2 (3.9 [CI 1.7-6.0]), and 4.2 (3.5% [CI 0.9-6.2]), respectively. The lobectomy and lymph-node-dissection rates increased (from 18.5% to 33.6%, p = 0.0014; and from 29.6% to 84.5%, p < 0.001; respectively), but the RAIT rate decreased (67.9-39.7%, p < 0.001) during the study period. During a median 6.3-year follow-up, two patients died. New treatment events occurred in 56 (10.7%) of patients in the initial surgery-only group (n = 523). In the initial surgery+RAIT group (n = 941), 316 patients received two or more RAITs within 2 years, and 80 (12.8%) of the remaining 625 patients underwent new treatment events. In the surgery+RAIT subgroup, the event-free survival rate was lower in 0-14-year olds than in 18-19-year olds (hazard ratio 2.5 [CI 1.4-4.4]). Conclusions: The pediatric thyroid cancer incidence increased from 2004 to 2012 in South Korea. The lobectomy and lymph-node-dissection rates increased, but the RAIT rate decreased. The higher risk for new treatment events in patients younger than 15 years requiring initial RAIT may be linked to advanced stage at diagnosis, and it needs to be further evaluated.

Measurements of Bone Health after Thyroid-Stimulating Suppression Therapy in Postmenopausal Women with Differentiated Thyroid Carcinoma: Bone Mineral Density versus the Trabecular Bone Score

Background: Thyroid-stimulating hormone (TSH) suppression therapy is an important treatment modality for differentiated thyroid carcinoma (DTC), but it increases fracture risk. The aim of this study was to evaluate changes in bone mineral density (BMD) and trabecular bone score (TBS) in postmenopausal DTC patients receiving TSH suppression therapy. Methods: A total of 410 postmenopausal DTC patients who underwent thyroidectomy and had at least two dual-energy X-ray absorptiometry measurements, including a preoperative measurement, were included. Patients who had osteoporosis medication for more than 1 year were classified as ‘patients with osteoporosis’. Results: In patients without osteoporosis, the change in %BMD was similar between TSH suppression (−) and (+) groups, while the decrease in %TBS was significantly greater in the TSH suppression (+) group than that of the TSH suppression (−) group. The relative risk of vertebral fracture was decreased by TBS changes but not by BMD changes. In patients with osteoporosis, both BMD and TBS showed significant increases in the TSH suppression (−) group but not in TSH suppression (+) group. At year 4, TBS was significantly lower in the TSH suppression (+) group than that in the TSH suppression (−) group, while BMD showed no difference between groups. Conclusions: TBS may better reflect bone health than BMD in postmenopausal DTC patients with TSH suppression therapy.

The new T3b category has clinical significance? SEER-based study

OBJECTIVE

As per the eighth edition of the American Joint Committee on Cancer (AJCC) staging system for differentiated thyroid carcinoma (DTC), minimal extrathyroidal extension (mETE) has been removed. Instead, gross ETE (gETE) invading only strap muscles has been designated as a new T3b category. Our objective was to investigate the impact of the T3b category on survival in order to establish its prognostic value in DTC.

DESIGN

In this retrospective study, we included patients who had undergone thyroidectomy between 2004 and 2012. Data from the Surveillance, Epidemiology and End Results (SEER) database were examined.

METHODS

We used the Kaplan-Meier method and log-rank test to analyse overall survival (OS) and cancer-specific survival (CSS). The effect of potential predictors associated with survival were estimated using the Cox regression model. To minimize selection bias, propensity-score matching (PSM) was performed.

RESULTS

A total of 63 315 patients were included in our study. During the average follow-up duration of nearly 78 months, significant differences were observed in cancer-specific survival among patients with no ETE, mETE, gETE invading only strap muscles (T3b) and gETE invading perithyroidal structures other than strap muscles (T4) (P < .05). In univariable and multivariate analysis, both mETE and T3b exhibited significant poorer CSS compared with no ETE. After adjusting for patient features with PSM, it was confirmed that T3b was associated with worse CSS compared with no ETE and mETE.

CONCLUSIONS

Both mETE and gETE are independent factors for DTC, implying that the new T3b category is worthy of reference for medical workers. Furthermore, mETE was significantly associated with poorer outcome. Our conclusion may provide support for the modification of the TNM staging system in the future.

The binary presence or absence of lymph node metastasis or extrathyroidal extension is not associated with survival in papillary thyroid cancers: Implications for staging systems

BACKGROUND

The characteristics of diagnosed papillary thyroid cancer (PTC) have changed over time with the increasing trend of early diagnosis, and the survival impact of conventional prognostic factors such as lymph node metastasis (LNM) and extrathyroidal extension (ETE) is controversial. We investigated PTC prognostic factors for overall survival (OS) and disease specific survival (DSS), focusing on LNM, ETE, and their implications for PTC staging systems.

METHODS

We assessed prognostic factors for OS and DSS in a nationwide sample of Korean PTC patients (N = 5192, median follow-up 121 months) using Cox regression. The binary presence or absence of LNM and ETE, as well as other measures of LNM and ETE, were examined for their survival impact. We also evaluated the relative performance of PTC staging systems before and after revising the staging criteria for LNM and ETE.

RESULTS

The binary presence of LNM or ETE was not a prognostic factor for OS or DSS, nor were other various measures of LNM. However, the extent of ETE as none, microscopic, or gross independently influenced survival (OS hazard ratio for gross vs. none: 3.28, 95% confidence interval (CI) 1.97-5.46; DSS hazard ratio for gross vs. none: 3.75, 95% CI 1.59-8.81). The performance of PTC staging systems improved when the extent of ETE and/or location of LNM were used as staging components.

CONCLUSION

The extent of ETE and/or location of LNM may be better survival indicators than their binary presence or absence, and we propose staging criteria revisions to pertinent staging systems to better reflect the contemporary PTC population.

Current trends in the features of male thyroid cancer: Retrospective evaluation of their prognostic value

This study aimed to compare the clinicopathologic characteristics and oncologic outcomes of papillary thyroid cancer (PTC) patients according to sex. Then, we validated prognostic variables to determine whether sex is a significant prognostic factor for PTC.Between January 2007 and December 2010, 1232 men and 7276 women PTC patients underwent surgery. The patient characteristics and 5-year oncologic outcomes were compared. The stepwise Cox proportional hazards model determined the significance of survival variables.Men PTC patients had more lymph node (LN) metastases than women, both in the total (P < .0001) and hemithyroidectomy (P < .0001) patients. Men and women showed similar 5-year recurrence-free survivals, both in total (P = .815) and hemithyroidectomy (P = .148) patients. The tumor size and the number of positive central nodes were associated with tumor recurrence, but not sex.Sex was not an independent prognostic factor for tumor recurrence. Multicenter clinical studies with long-term follow-ups are needed to validate these results.

Star-Shaped Intense Uptake of ¹³¹I on Whole Body Scans Can Reflect Good Therapeutic Effects of Low-Dose Radioactive Iodine Treatment of 1.1 GBq

BACKGROUND

After initial radioactive iodine (RAI) treatment in differentiated thyroid cancer patients, we sometimes observe a star-shaped region of intense uptake of ¹³¹I on whole body scans (WBSs), called a 'star artifact.' We evaluated the clinical implications of star artifacts on the success rate of remnant ablation and long-term prognosis.

METHODS

Total 636 patients who received ¹³¹I dose of 1.1 GBq for the initial RAI therapy and who did not show distant metastasis at the time of diagnosis were retrospectively evaluated. A negative second WBS was used for evaluating the ablation efficacy of the RAI therapy. Among them, 235 patients (36.9%) showed a star artifact on their first WBS.

RESULTS

In patients with first stimulated thyroglobulin (sTg) levels ≤2 ng/mL, patients with star artifacts had a higher rate of negative second WBS compared with those without star artifacts (77.8% vs. 63.9%, P=0.044), and showed significantly higher recurrence-free survival (P=0.043) during the median 8.0 years (range, 1.0 to 10.0) of follow-up. The 5- and 10-year recurrence rates (5YRR, 10YRR) were also significantly lower in patients with star artifacts compared with those without (0% vs. 4.9%, respectively, P=0.006 for 5YRR; 0% vs. 6.4%, respectively, P=0.005 for 10YRR). However, ablation success rate or recurrence-free survival was not different among patients whose first sTg levels >2 ng/mL regardless of star artifacts.

CONCLUSION

Therefore, star artifacts at initial RAI therapy imply a good ablation efficacy or a favorable long-term prognosis in patients with sTg levels ≤2 ng/mL.

Prognostic significance of gross extrathyroidal extension invading only strap muscles in differentiated thyroid carcinoma

Background

In the eighth edition of the AJCC staging system for differentiated thyroid carcinoma (DTC), minimal extrathyroidal extension (ETE) is no longer a determinant of T3 category. Instead, gross ETE invading only strap muscles has been designated as a new T3b category. The long-term prognosis of patients with DTC and gross ETE invading only strap muscles was investigated.

Methods

This was a retrospective analysis of patients who underwent thyroidectomy between 1996 and 2005. Differences in cancer-specific and recurrence-free survival according to extent of ETE were assessed.

Results

A total of 3174 patients with DTC were included. No significant differences were observed in 10-year cancer-specific survival among patients with no ETE (98·6 per cent), microscopic ETE (98·3 per cent) and gross ETE invading only strap muscles (98·9 per cent) (P = 0·375). The 10-year recurrence-free survival rate for patients with gross ETE invading only strap muscles (89·2 per cent) was shorter than that for patients with no ETE (93·7 per cent; P = 0·016), but similar to that of patients with microscopic ETE (90·3 per cent). In univariable analysis, patients with gross ETE invading only strap muscles had a significantly higher risk of recurrence than those with no ETE (hazard ratio (HR) 1·67, 95 per cent c.i. 1·10 to 2·55; P = 0·017). In multivariable analysis, gross ETE invading only strap muscles was not an independent predictor of recurrence (HR 1·09, 0·71 to 1·69; P = 0·685).

Conclusion

Although gross ETE invading only strap muscles may provide prognostic information about long-term recurrence, it does not affect mortality. The actual impact of gross ETE invading only strap muscles will be important in revising the staging system in the future.

Clinical Characteristics of Subtypes of Follicular Variant Papillary Thyroid Carcinoma

BACKGROUND

Among follicular variant papillary thyroid carcinomas (FVPTCs), the noninvasive encapsulated subtype has an excellent prognosis. For this reason, reclassification of noninvasive encapsulated FVPTC (EFVPTC) as a new entity called "noninvasive follicular thyroid neoplasm with papillary-like nuclear features" (NIFTP) has been proposed, but controversy remains. To characterize noninvasive EFVPTC in an Asian population, the clinicopathologic features of each FVPTC subtype were compared in a Korean population.

METHODS

FVPTC patients (n = 142) who underwent thyroidectomy between 2009 and 2014, and whose tumor size was >1 cm, were included in the study. The surgical pathology of each patient was reevaluated by two independent expert pathologists.

RESULTS

The percentages of noninvasive and invasive EFVPTC and infiltrative FVPTC (IFVPTC) in the study were 30%, 31%, and 39%, respectively. There was no difference in preoperative cytological diagnosis or the extent of surgery between noninvasive and invasive EFVPTC. However, the proportion of Bethesda category IV was lower in IFVPTC (16%) than in noninvasive and invasive EFVPTC (35% and 36%, respectively). Therefore, thyroid lobectomy was more common in noninvasive or invasive EFVPTC (54% or 48%, respectively) than in IFVPTC (16%). Noninvasive EFVPTC showed lower multiplicity, extrathyroidal extension, and BRAF^V600E mutation frequency (three cases; 8%) than did invasive EFVPTC, but other pathological characteristics were similar. However, IFVPTC showed significant differences in tumor size, extrathyroidal extension, lymph node metastasis, Tumor Node Metastasis stage, and American Thyroid Association high-risk category compared with noninvasive and invasive EFVPTC. In the noninvasive EFVPTC group, there were six (14%) cases with multifocality and three (7%) cases with lymph node metastasis. However, only two cases with multifocality and one case with lymph node metastasis originated from noninvasive FVPTC, while the other cases were from coexisting conventional PTCs.

CONCLUSIONS

Noninvasive EFVPTC has favorable pathological features, but lymph node metastasis or BRAF^V600E mutations were observed in some patients. Therefore, in order for the distinction between noninvasive EFVPTC and invasive EFVPTC to have more clinical significance, the criteria for NIFTP need to be more strictly revised.

Changes in the clinicopathological characteristics and genetic alterations of follicular thyroid cancer

OBJECTIVE

Changes in the clinicopathological characteristics and genetic alterations of follicular thyroid cancer (FTC) over time have not been reported. Moreover, the prognostic effects of RAS and TERT promoter mutations in FTC have not been clearly elucidated. We investigated changes in the clinicopathological characteristics of patients with FTC over four decades, as well as the clinical significance of genetic mutations of FTC.

DESIGN AND METHODS

This retrospective study included 690 patients with FTC who underwent thyroidectomy between 1973 and 2015 at the Seoul National University Hospital. In 134 samples, genetic tests for N/H/KRAS and TERT promoter mutations and PAX8/PPARγ rearrangement were performed.

RESULTS

The age at diagnosis has increased (P < 0.001) in recent decades and extrathyroidal extension of the tumor has become less common (P = 0.033). Other clinicopathological characteristics and prognosis of FTC have not significantly changed. The prevalence of RAS mutations decreased (P = 0.042) over time, whereas that of TERT promoter mutations remained stable. RAS mutations were associated with distant metastasis and persistent disease, and TERT promoter mutations were associated with distant metastasis, advanced TNM stage, recurrence and disease-specific mortality. FTC patients with coexistent RAS and TERT promoter mutations showed a higher recurrence risk than those with only one mutation.

CONCLUSIONS

The age at diagnosis of FTC and the frequency of extrathyroidal extension have changed over four decades. Moreover, the prevalence of RAS mutations decreased. RAS and TERT promoter mutations may be associated with poor clinical outcomes in FTC, especially when the two mutations coexist.

Heterogeneous Prognoses for pT3 Papillary Thyroid Carcinomas and Impact of Delayed Risk Stratification

BACKGROUND

Papillary thyroid carcinomas (PTC) in the pT3 category constitute a heterogeneous group of tumors with a variable risk of recurrence. The objectives of this study were (i) to estimate disease-free survival (DFS) and identify prognostic factors associated with recurrence in a cohort of pT3 PTC, and (ii) to evaluate the concept of delayed risk stratification in a cohort of pT3 tumors.

METHODS

A total of 560 patients with pT3 PTC, treated and followed at the authors' institution, were studied. They were divided into three groups: group 1, pT3 ≤10 mm; group 2, pT3 >10 mm with extrathyroidal invasion (ETI); and group 3, pT3 due to a tumor size >4 cm. DFS was estimated using the Kaplan-Meier method, and associated prognostic features were studied in univariate and multivariate Cox model-based analyses in each group. Then, DFS was studied for each group according to the six- to eight-month status (remission or not).

RESULTS

DFS at 10 years was 75% for the entire cohort and was 89%, 67%, and 82% in groups 1, 2, and 3, respectively (p < 0.0001). Multivariate analysis identified three factors significantly associated with reduced DFS: lymph node (LN) involvement, male sex, and group 2 (>1 cm with ETI). A trend toward a worse prognosis in patients with pT3 N0/Nx PTC >10 mm with ETI was found in comparison with the other pT3 N0/Nx patients. When the six- to eight-month checkup was normal, the DFS at 10 years increased to 98%, 96%, and 91% in groups 1-3, respectively. Furthermore, in this case, initial LN involvement no longer seemed to affect the prognosis in those groups.

CONCLUSION

PTC ≤10 mm with ETI and large tumors >4 cm without ETI both have a low-recurrence risk when there are no adverse associated prognostic features such as LN involvement. LN involvement, especially in the lateral compartment (N1b), is a strong prognostic factor of recurrence in pT3 PTC. Delayed risk stratification can be applied in pT3 PTC patients. Those cured at the first checkup, including those with limited LN involvement, have excellent outcomes, which should prompt clinicians to adapt subsequent management accordingly.

Anaplastic Thyroid Cancer in Sicily: The Role of Environmental Characteristics

BACKGROUND

Anaplastic thyroid cancer (ATC) is a rare but extremely aggressive cancer of the thyroid, contributing up to 30-40% of thyroid cancer-specific mortality. We analyzed ATC characteristics and survival rates in Sicily to evaluate the possible influence of environmental factors. With this aim, data regarding ATC incidences in urban/rural and industrial, iodine-deficient, and volcanic vs control areas were compared in Sicily as well as ATC data from Sicily and USA.

METHODS

Using the Sicilian Register of Thyroid Cancer (SRTC) database incidence, age, gender, tumor size and histotype, extrathyroidal extension, stage, and coexistence with pre-existing differentiated thyroid cancer (DTC) were evaluated in different areas of Sicily and also compared with Surveillance Epidemiology and End Results data in USA.

RESULTS

Forty-three ATCs were identified in Sicily in the period 2002-2009. In our series only age <70 years at diagnosis (p = 0.01), coexistence with DTC (p = 0.027) and tumor size ≤6 cm (p = 0.012) were significant factors for increased survival at univariate analysis (only age at multivariate analysis). No difference in ATC incidence was found in urban vs rural areas and in iodine-deficient and industrial vs control areas. By contrast, in the volcanic area of Sicily, where DTC incidence is doubled relative to the rest of the island, also ATC incidence was increased. ATC data in Sicily were similar to those reported in the same period in the USA where overall survival rate at 6 and 12 months, however, was smaller.

CONCLUSION

The similar ATC data observed in Sicily and USA (having different genetic background and lifestyle) and the increased ATC incidence in the volcanic area of Sicily paralleling the increased incidence of papillary thyroid cancer are compatible with the possibility that casual additional mutations, more frequent in a background of increased cell replication like DCT, are the major causes of ATC rather than genetic background and/or direct environmental influences.

Postoperative biochemical remission of serum calcitonin is the best predictive factor for recurrence-free survival of medullary thyroid cancer: a large-scale retrospective analysis over 30 years

CONTEXT

The increase in thyroid screening in the general population may lead to earlier detection of medullary thyroid carcinoma (MTC).

OBJECTIVE

We aimed to evaluate secular trends in clinicopathological characteristics and long-term prognosis of MTC and its prognostic factors.

DESIGN

This was a retrospective analysis from 1982 to 2012.

PATIENTS

Three hundred and thirty-one patients with MTC were included and grouped based on the year of diagnosis (1982-2000, 2001-2005, 2006-2010 and 2011-2012).

MEASUREMENTS

These included recurrence and mortality as well as biochemical remission (BCR) of serum calcitonin.

RESULTS

Mean tumour size (from 2·5 cm to 1·7 cm, P < 0·001) and percentage of extrathyroidal extension (from 52·0% to 26·0%, P = 0·026) decreased. The percentage of patients achieving BCR within six postoperative months (po-BCR) increased with time (from 39·6% to 76·1%, P < 0·001). The 5-year overall recurrence rate significantly decreased in 2006-2012 compared to 1982-2005 (10% vs 18%, respectively, P = 0·031), although the 5-year survival rate did not improve (92% vs 92%, P = 0·929). Failure to achieve po-BCR was the strongest predictive factor associated with recurrence (hazard ratio [HR] = 58·04, 95% CI 7·14-472·11; P < 0·001). Male gender (HR = 3·18, 95% CI 1·18-8·56; P = 0·022), tumour size >2 cm (HR = 18·33, 95% CI 2·35-143·06; P = 0·006) and distant metastasis (HR = 4·00, 95% CI 1·31-12·21; P = 0·015) were significant prognostic factors for mortality.

CONCLUSIONS

Clinicopathological characteristics and recurrence of MTC improved with time. Po-BCR was the best predictive factor for recurrence-free survival.

Prognostic effects of TERT promoter mutations are enhanced by coexistence with BRAF or RAS mutations and strengthen the risk prediction by the ATA or TNM staging system in differentiated thyroid cancer patients

BACKGROUND

Recent reports suggest that mutations in the promoter of the gene encoding telomerase reverse transcriptase (TERT) affect thyroid cancer outcomes.

METHODS

In all, 551 patients with differentiated thyroid cancer (DTC) enrolled in this study. The median follow-up duration was 4.8 years (interquartile range, 3.4-10.6 years).

RESULTS

TERT promoter mutations were detected in 25 DTCs (4.5%): 2.8% in neither BRAF-mutated nor RAS-mutated tumors, 4.8% in BRAF-mutated tumors, and 11.3% in RAS-mutated tumors. Moreover, they were frequently observed in American Thyroid Association (ATA) high-risk and TNM stage III/IV groups (9.1% and 12.9%, respectively). The coexistence of BRAF or RAS with TERT promoter mutations increased aggressive clinicopathologic features, recurrence (hazard ratio [HR] for BRAF, 4.64; 95% confidence interval [CI], 1.42-15.18; HR for RAS, 5.36; 95% CI, 1.20-24.02), and mortality (HR for BRAF, 15.13; 95% CI, 1.55-148.23; HR for RAS, 14.75; 95% CI, 1.30-167.00), even after adjustments for the age at diagnosis and sex, although the significance was lost after additional adjustments for pathologic characteristics. Furthermore, TERT promoter mutations significantly increased the risk of both recurrence and mortality in the ATA high-risk (HR for recurrence, 5.79; 95% CI, 2.07-16.18; HR for mortality, 16.16; 95% CI, 2.10-124.15) and TNM stage III/IV groups (HR for recurrence, 3.60; 95% CI, 1.19-10.85; HR for mortality, 9.06; 95% CI, 2.09-39.26).

CONCLUSIONS

The coexistence of BRAF or RAS mutations enhanced the prognostic effects of TERT promoter mutations. Furthermore, TERT promoter mutations strengthened the predictions of mortality and recurrence by the ATA and TNM staging systems, particularly for high-risk patients with DTC. Cancer 2016;122:1370-1379. © 2016 American Cancer Society.

Increased Risk of Leukemia After Radioactive Iodine Therapy in Patients with Thyroid Cancer: A Nationwide, Population-Based Study in Korea

BACKGROUND

The use of radioactive iodine therapy (RAIT) is increasing in thyroid cancer management. The association between RAIT at high doses and leukemia is well known, but studies of this association in a large population are lacking. This study aims to investigate the association between RAIT and leukemia in the context of current practice.

METHODS

Retrospective analysis of a 542,845 person-year (PY) follow-up of thyroid cancer patients was conducted using the Korean National Health Insurance claims database between January 2008 and December 2013. Patients were categorized according to RAIT dose (no RAI; low dose, ≤30 mCi; moderate dose, 31-100 mCi; high dose, 101-150 mCi; and very high dose, >150 mCi).

RESULTS

Among 211,360 thyroid cancer patients, 72 (0.03%) patients developed leukemia during follow-up (median 877 days). The cumulative incidence of leukemia per 10(5) person-year (PY) was 9.8 in the no RAI [95% confidence interval (CI) 6.4-14.4]; 6.1 [CI 1.7-15.7] in the low-dose; 8.6 [CI 3.2-18.7] in the moderate-dose; 29.5 [CI 18.3-45.1] in the high-dose; and 20.9 [CI 11.7-34.4] in the very high-dose groups. The hazard ratios were elevated significantly in the high- and very high-dose groups (HR 3.1 and 2.1, respectively, p<0.001) when compared with the no RAI group.

CONCLUSIONS

RAIT exceeding 100 mCi was strongly associated with the development of leukemia in a nationwide, population-based study, while lower RAIT doses were not. Considering the favorable survival of patients with thyroid cancer and the potential harm of RAIT, physicians need to consider the pros and cons of RAIT when using this treatment option.

Pediatric patients with multifocal papillary thyroid cancer have higher recurrence rates than adult patients: a retrospective analysis of a large pediatric thyroid cancer cohort over 33 years

CONTEXT

Large-sample studies with long-term follow-up data are limited for pediatric patients with thyroid cancer.

OBJECTIVE

Secular changes in clinicopathological characteristics and outcomes in pediatric patients with thyroid cancer were investigated and compared with those of adults.

DESIGN AND PATIENTS

A retrospective review of 150 pediatric patients with thyroid cancer managed between 1980 and 2013 was conducted. The long-term outcomes of 124 patients followed up for 12 months or longer were evaluated. Predictors of recurrence-free survival (RFS) in pediatric patients with papillary thyroid cancer (ped-PTC group) were compared with those of 3071 adult patients.

RESULTS

The proportion of small tumors (<1 cm) increased from 9.0% before 2010 to 36.8% after 2010 (P < .001); however, neither pathological presentations such as multifocality, extrathyroidal extension (ETE), lymph node (LN) metastasis, or lung metastasis nor the RFS rate changed over time. The 5- and 10-year recurrence rates were 14.5% and 34.4% in pediatric patients, respectively. In respective analyses of the ped-PTC group and patients of all ages with papillary thyroid cancer (all ages group), the rates of ETE, LN metastasis, and lung metastasis were higher with younger age (all P for trend <.05). RFS was lower in the pediatric than the adult patients aged 20-54 years (P < .005) and was comparable with that of older patients (≥ 55 y). Only tumor multifocality and size predicted recurrence in the ped-PTC group (P < .05), whereas LN metastasis and ETE also predicted recurrence in the all-ages group (P < .01). Among patients in the all-ages group with multifocal tumors, pediatric patients had the lowest RFS (P < .05).

CONCLUSIONS

The pathological characteristics and recurrence rates of pediatric thyroid cancer have not changed over 33 years. Although younger patients present with more advanced disease, multifocality rather than age at diagnosis predicted recurrence. Recurrence was higher in pediatric than adult patients with multifocal papillary thyroid cancer.