Presumed Pathogenic Germ Line and Somatic Variants in African American Thyroid Cancer

Background: African American (AA) thyroid cancer patients have worse prognoses than European Americans (EA), which has been attributed to both health care disparities and possible genetic differences. We investigated the impact of both germ line and somatic variants on clinical outcome in a cohort of AA nonmedullary thyroid cancer (NMTC) patients who had received therapeutic intervention from cancer centers. Methods: Whole-exome sequencing was performed on DNA from available blood/normal tissues (N = 37) and paired tumor samples (N = 32) collected from 37 and 29 AA NMTC patients, respectively. Variants with Combined Annotation Depletion Dependent (CADD) score of ≥20 and VarSome Clinical classification of likely pathogenic or pathogenic were classified as presumed pathogenic germ line or somatic variants (PPGVs/PPSVs). PPGVs/PPSVs in cancer-related genes and PPGVs in cardiovascular risk genes were further investigated, and PPGVs/PPSVs associated with African (AFR) ancestry were identified. Results: Among 17 PPGVs identified in 16 cancer predisposition or known cancer-related genes, only WRN was previously known to associate with NMTC predisposition. Among PPSVs, BRAFV600E was most the prevalent and detected in 12 of the 29 (41%) tumors. Examining PPGVs/PPSVs among three patients who died from NMTC, one patient who died from papillary thyroid carcinoma/anaplastic thyroid carcinoma (PTC/ATC) led us to speculate that the PPGV ERCC4R799W may have increased the risk of PPSV TP53R273H acquisition. Among PPGVs identified in 18 cardiovascular risk genes, PPGVs in SC5NA, GYG1, CBS, CFTR, and SI are known to have causal and pathogenic implications in cardiovascular disease. Conclusion: In this cohort, most AA-NMTC patients exhibit favorable outcomes after therapeutic intervention given at cancer centers, suggesting that health care disparity is the major contributor for worse prognoses among AA-NMTC patients. Nevertheless, the clinical impact of PPGVs that might facilitate the acquisition of TP53 tumor mutations, and/or PPGVs that predispose individuals to adverse cardiovascular events, which could be exacerbated by therapy-induced cardiotoxicity, needs to be further explored. Integrated analysis of PPGV/PPSV profiles among NMTC patients with different stages of disease may help to identify NMTC patients who require close monitoring or proactive intervention.

Ultrasound Features and Performance of Afirma Gene Sequencing Classifier in Cytologically Indeterminate Thyroid Nodules

Background

Cytologically indeterminate thyroid nodules (ITN) pose a management challenge. Here we analyze if adding ultrasound characteristics to Afirma Genome Sequence Classifier (GSC) results increases GSC diagnostic performance.

Methods

We retrospectively analyzed 237 GSC-tested Bethesda III/IV ITNs between July 2017 and December 2019 and classified them by American Thyroid Association (ATA) and the Thyroid Imaging Reporting and Data System (TIRADS) of the American College of Radiology.

Results

The benign call rate was higher in Bethesda III ITNs with TIRADS <5 vs TIRADS 5 (89% vs 68%. P = .015). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of GSC in ATA high-risk Bethesda III ITNs vs lower were 100% vs 80% (P = 1), 89.5% vs 91.5% (P = .67), 66.7% vs 25% (P = .13), and 100% vs 99.2% (P = 1), respectively, and for TIRADS 5 vs <5 were 100% vs 80% (P = 1), 88.2% vs 91.4% (P = .65), 71.4% vs 23.5% (P = .06), and 100% vs 99.3% (P = 1). The sensitivity, specificity, PPV, and NPV of GSC in high-risk ATA Bethesda IV ITNs vs lower were 66.7% vs 100% (P = .42), 83.3% vs 85.7% (P = 1), 66.7% vs 64.3% (P = 1), and 83.3% vs 100% (P = .3), respectively, and for TIRADS 5 vs <5 were 66.7% vs 90% (P = .42), 88.9% vs 83.8% (P = 1), 66.7% vs 60% (P = 1), and 88.9% vs 96.9% (P = .39).

Conclusion

Sensitivity, specificity, NPV, and PPV of GSC were not significantly different in ATA high-risk and TIRADS 5 ITNs compared to ATA < high-risk and TIRADS 1-4 ITNs.

Thyroid cancer, recent advances in diagnosis and therapy

Over the past several decades, the approach to the diagnosis and management of patients with follicular cell-derived thyroid cancer has evolved based on improved classification of patients better matching clinical outcomes, as well as advances in imaging, laboratory, molecular technologies and knowledge. While thyroid surgery, radioactive iodine therapy and TSH suppression remain the mainstays of treatment, this expansion of knowledge has enabled de-escalation of therapy for individuals diagnosed with low-risk well-differentiated thyroid cancer; better definition of treatment choices for patients with more aggressive disease; and improved ability to optimize treatments for patients with persistent and/or progressive disease. Most recently, the advancement of knowledge regarding the molecular aspects of thyroid cancer has improved thyroid cancer diagnosis and has enabled individualized therapeutic options for selected patients with the most aggressive forms of the disease. Guidelines from multiple societies across the world reflect these changes, which focus on taking a more individualized approach to clinical management. In this review, we discuss the current more personalized approach to patients with follicular cell-derived thyroid cancer and point toward areas of future research still needed in the field.

Features of Cytologically Indeterminate Molecularly Benign Nodules Treated With Surgery

BACKGROUND

Most cytologically indeterminate thyroid nodules (ITNs) with benign molecular testing are not surgically removed. The data on clinical outcomes of these nodules are limited.

METHODS

We retrospectively analyzed all ITNs where molecular testing was performed either with the Afirma gene expression classifier or Afirma gene sequencing classifier between 2011 and 2018 at a single institution.

RESULTS

Thirty-eight out of 289 molecularly benign ITNs were ultimately resected. The most common reason for surgery was compressive symptoms (39%). In multivariable modeling, patients aged <40 years, nodules ≥3 cm, presence of an Afirma suspicious nodule other than the index nodule, and compressive symptoms were associated with higher surgery rates with hazard ratios for surgery of 3.5 (P < 0.001), 3.2 (P < 0.001), 16.8 (P < 0.001), and 7.31 (P < 0.001), respectively. Of resected nodules, 5 were malignant. False-negative rate (FNR) was 1.7%, presuming all unresected nodules were truly benign and 13.2% restricting analysis to resected cases. The FNR was significantly higher in nodules with a high-risk sonographic appearance for cancer (American Thyroid Association high-risk classification and American College of Radiology Thyroid Imaging Reporting and Data Systems score of 5) compared with nodules with all other sonographic categories (11.8% vs 1.1%; P = 0.03 and 11.1% vs 1.1%; P = 0.02, respectively).

CONCLUSIONS

Younger age, larger nodule size, presence of an Afirma suspicious nodule other than the index nodule, and compressive symptoms were associated with a higher rate of surgery. The FNR of benign Afirma was significantly higher in nodules with high-risk sonographic features.

MON-530 Local Lymph Node Metastasis Is Less Common in RAS- Mutated Thyroid Cancer Compared to BRAFV600E- Mutated Thyroid Cancer

Introduction: Somatic mutations of RAS- and BRAFV600E- are the most common driver mutation in thyroid cancer (TC) and in the majority of cases, these are mutually exclusive^1,2. Clinical characteristics of TC with either RAS or BRAFV600E mutation is not systemically studied.

Methods: This is a retrospective study at the Ohio State University (OSU) from 1/2000 to 12/2018. Data were extracted from OSU Endocrine Neoplasia Repository (ENR). Medullary thyroid cancer was excluded. The treating physician determined patient management. Statistical analysis was performed with the chi-square test for categorical values and Mann-Whitney U test for continuous unpaired values. Two-sided P values of less than 0.05 were considered statistically significant.

Results: Out of 320 patients, 152 patients had a positive mutational profile. Of these, 128 patients had a BRAFV600E mutation and 14 had a RAS mutation. Details of RAS mutation were as follows; NRASQ61K (n=2), NRASQ61R (n=1), HRASQ61R (n=1), HRASQ61K (n=1), NRAS without further details (n=9). Local lymph node metastasis was significantly less in RAS mutated cancer (58% vs 16%, p<0.05). Lymph node metastasis was limited to N1a in all RAS group, whereas 38% of BRAFV600E had N1b status. The number of positive lymph nodes were significantly fewer in the RAS group (mean 0.42 vs. 9.1, p=0.003). None of the patients in RAS group developed subsequent local neck recurrence, whereas 19% of BRAFV600E group developed a recurrence (p=0.05). Bone metastasis was more common in RAS compared to BRAFV600E group (21% vs 6%, p=0.04) but there were no differences in other distant metastases. Presence of extrathyroidal extension was significantly higher in BRAFV600E compared to RAS group (58 % vs 8%; p=0.04). Classic variant papillary thyroid cancer was the most common histologic diagnosis with both mutations, however, follicular-variant papillary thyroid cancer was more common in RAS than BRAFV600E group (29% vs 8%, p=0.04) and follicular thyroid cancer was only seen in the RAS group (25% vs 0%, p<0.05). There was no difference in gender, age at diagnosis, disease status after initial therapy, RAI treatment, RAI dosage, and mortality between the groups.

Conclusion: Thyroid cancer associated with a RAS-mutation has less tendency to metastasize locally and has a higher incidence of bone metastasis compared to thyroid cancer with BRAFV600E-mutation. Individualized clinical follow up may be indicated depends on their mutational profile.

References:

1. Cancer Genome Atlas Research N. Integrated genomic characterization of papillary thyroid carcinoma. Cell. 2014;159(3):676-690.

2. Nikiforova MN, Lynch RA, Biddinger PW, et al. RAS point mutations and PAX8-PPAR gamma rearrangement in thyroid tumors: evidence for distinct molecular pathways in thyroid follicular carcinoma. J Clin Endocrinol Metab. 2003;88(5):2318-2326.

Vandetanib-induced Phototoxic Drug Eruption Treated with Polypodium Leucotomos Extract: A Case Report and Review of the Literature

Vandetanib is a tyrosine kinase inhibitor approved by the United States Food and Drug Administration for the treatment of metastatic medullary thyroid cancer. It has been linked to a variety of dermatologic reactions, including photosensitivity. We describe the case of a 55-year-old man who developed a severe, painful, erythematous, bullous eruption in sun-exposed areas one month after the initiation of vandetanib. The eruption was initially refractory to treatment with steroids and did not resolve with strict sun avoidance, but finally cleared after a few weeks of oral supplementation with Polypodium leucotomos (P. leucotomos) extract. P. leucotomos is an extract derived from a tropical fern, with antioxidant effects that mitigate ultraviolet-induced cutaneous erythema via inflammatory interference and the promotion of other cytotoxic responses. This case illustrates the potential for P. leucotomos to be used as a safe and effective photoprotective agent for refractory phototoxic reactions. Further randomized, controlled trials are needed to better understand the mechanism of action and photoprotective properties of P. leucotomos in the treatment of tyrosine kinase-induced phototoxicity and other dermatoses.

Afirma Gene Sequencing Classifier Compared with Gene Expression Classifier in Indeterminate Thyroid Nodules

Background: The Afirma Gene Expression Classifier (GEC) has been used to further characterize cytologically indeterminate (cyto-I) thyroid nodules into either benign or suspicious categories. However, its relatively low positive predictive value (PPV) limited its use as a classifier for patients with suspicious results. The Afirma Gene Sequencing Classifier (GSC) was developed to improve PPV while maintaining a high negative predictive value (NPV), yet real-world assessment of its performance is lacking. Methods: We analyzed all patients who had cyto-I nodules and molecular testing with either GEC or GSC between 2011 and 2018 at a single academic medical center. Clinical information was obtained for 343 GEC-tested nodules and 164 GSC-tested nodules. Results: The GSC had a statistically significant higher benign call rate (76.2% vs. 48.1%, p < 0.001), PPV (60.0% vs. 33.3%, p = 0.01), and specificity (94.3% vs. 61.4%, p < 0.001) than the GEC. Improvement was statistically significant in both Bethesda III and Bethesda IV nodules. In particular, the benign call rate of GSC was significantly higher in nodules with Hürthle cell changes (88.8% vs. 25.7%, p < 0.01). The rate of surgical intervention in the indeterminate nodule cohort has decreased by 66.4% since switching to the GSC; 52.5% of indeterminate nodules went to surgery while using the GEC compared with 17.6% with the GSC (p < 0.001). This reduction was statistically significant in nodules with Bethesda III diagnoses, demonstrating a 70.9% decrease (GEC 51.3% vs. GSC 14.9%, p < 0.001), and in nodules with Bethesda IV cytology, a 39.2% decrease was noted (GEC 54.8% vs. GSC 33.3%, p = 0.003). Conclusions: Data from a single academic tertiary center show an improved specificity and PPV while maintaining high sensitivity and NPV for GSC compared with GEC. A statistically significant increase in benign call rates was observed in GSC compared with GEC, likely indicating fewer false positive results. After implementation of GSC, surgical interventions have been reduced by 68%.

Risk Haplotypes Uniquely Associated with Radioiodine-Refractory Thyroid Cancer Patients of High African Ancestry

BACKGROUND

Thyroid cancer patients with radioiodine-refractory (RAI-R) disease, resulting from insufficient RAI delivery and/or RAI resistance, have increased mortality and limited treatment options. To date, studies have largely focused on tumor mutations associated with different stages of disease, which could provide prognostic value for RAI-R disease. It was hypothesized that germline variants contributing to intrinsic differences in iodine metabolism, tumor microenvironment, and/or immune surveillance are associated with RAI-R disease.

METHODS

Whole-genome genotyping data analysis was performed on 1145 Caucasian (CAU) patients, 244 of whom were RAI-R, and 55 African American (AA) patients, nine of whom were RAI-R. Germline-variant association studies were conducted using candidate genes involved in iodine metabolism or DNA-damage repair, as well as genome-wide association analysis. Initial data indicated several notable variants in a small number of patients (n = 7), who were later determined to be AA patients of >80% African ancestry (n = 37). This led to the study focusing on germline single nucleotide polymorphisms uniquely associated with RAI-R AA patients. Sanger sequencing was performed to validate risk alleles and identify the incidence of the common somatic mutations BRAF^V600E, NRAS^Q61R, and HRAS^Q61R in AA patients whose primary tumor samples were available (28/55).

RESULTS

TG, BRCA1, and NSMCE2 haplotypes were identified as being uniquely associated with RAI-R AA patients of >80% African ancestry. All patients with the TG haplotype (n = 4) had a biochemical incomplete response to RAI therapy. Patients with the NSMCE2 haplotype (n = 4) were diagnosed at a young age (13, 17, 17, and 26 years old) with distant metastatic disease at initial diagnosis. The BRCA1 haplotype co-occurred in three out of four patients with the NSMCE2 haplotype. The incidence of BRAF^V600E appears lower in papillary thyroid carcinomas from AA patients of >80% African ancestry (3/14; 21%) than in AA patients of <80% African ancestry (6/9; 67%), albeit only just approaching statistical significance (p = 0.077). The tumors available from three RAI-R AA patients were negative for BRAF^V600E, NRAS^Q61R, and HRAS^Q61R.

CONCLUSIONS

The identification of candidate RAI-R risk haplotypes may allow early stratification of clinical manifestations of RAI-R disease followed by early intervention and personalized treatment strategies. Functional annotation of candidate RAI-R risk haplotypes may provide insights into the mechanisms underlying RAI-R disease.

Long-Term Efficacy of Lymph Node Reoperation for Persistent Papillary Thyroid Cancer: 13-Year Follow-Up

BACKGROUND

Current recommendations for persistent or recurrent locoregional papillary thyroid cancer (PTC) include consideration of surgical resection versus active surveillance. The purpose of this study is to determine long-term outcomes after surgical resection of recurrent or persistent metastatic PTC in cervical lymph nodes after failure of initial surgery and radioactive iodine therapy using newer validated clinical outcomes measures.

METHODS

Outcomes of 70 patients who underwent cervical lymphadenectomy (n = 110) from 1999 to 2013 for recurrent or persistent locoregional PTC metastases were reviewed. Measures included biochemical remission (BCR) based on Tg levels, American Thyroid Association classifications for response to treatment [biochemical incomplete response (BIR), structural incomplete response (SIR), indeterminate response (IR), and excellent response (ER)], need for reoperation, surgical complications, disease progression, and death.

RESULTS

The median follow-up was 13.1 years, with only two additional reoperations since 2010, one of which had no metastasis on pathology with the other developing anaplastic thyroid cancer in background PTC. ER was achieved in 31 (44%) patients, all of whom remained in ER at time of last follow-up (median 14.1 years). There were no structural recurrences in patients with persistent BIR or IR after reoperation. Patients with SIR had stable disease, except for one who died due to anaplastic thyroid cancer.

CONCLUSIONS

Patients who achieved ER after reoperation had no need for further treatment. Patients with persistent detectable Tg levels after reoperation rarely developed structural recurrence. ATA outcomes can be safely used to guide treatment decisions over a decade after reoperation for PTC.

Heterogeneity in Positive Predictive Value of RAS Mutations in Cytologically Indeterminate Thyroid Nodules

BACKGROUND

RAS mutations are common in the available mutational analysis of cytologically indeterminate (Cyto-I) thyroid nodules. However, their reported positive predictive value (PPV) for cancer is widely variable. The reason for this variability is unknown, and it causes clinical management uncertainty. A systematic review was performed, evaluating the PPV for cancer in RAS mutation positive Cyto-I nodules, and variables that might affect residual heterogeneity across the different studies were considered.

METHODS

PubMed was searched through February 22, 2017, including studies that evaluated at least one type of RAS mutation in Cyto-I nodules, including any (or all) of the Bethesda III/IV/V categories or their equivalents and where the histological diagnosis was available. The PPV residual heterogeneity was investigated after accounting for Bethesda classification, blindedness of the histopathologist to the RAS mutational status, Bethesda category-specific cancer prevalence for each study, and which RAS genes and codons were tested. This was studied using five meta-regression models fit to different sets of Bethesda classification categories: Bethesda III, IV, or V (III/IV/V); Bethesda III or IV (III/IV); Bethesda III only; Bethesda IV only; and Bethesda V only.

RESULTS

Of 1831 studies, 23 were eligible for data inclusion. Wide ranges of PPV were found at 0-100%, 28-100%, and 0-100% in Bethesda III, IV, and V, respectively. Residual heterogeneity remained moderately high for PPV after accounting for the above moderators for Bethesda III/IV/V (21 studies; I² = 59.5%) and Bethesda III/IV (19 studies; I² = 66.0%), with significant Cochran's Q-test for residual heterogeneity (p < 0.001). Among individual Bethesda categories, residual heterogeneity was: Bethesda III (eight studies; I² = 89.0%), IV (12 studies; I² = 53.5%), and V (10 studies; I² = 34.4%), with significant Cochran's Q-test for Bethesda III (p < 0.001) and IV (p = 0.04).

CONCLUSION

The PPV of RAS mutations in Bethesda III and IV categories is quite heterogeneous across different studies, creating low confidence in the accuracy of a single estimate of PPV. Clinicians must appreciate this wide variability when managing a RAS-mutated Cyto-I nodule. Future studies should seek to resolve this unexplained variability.

Endocrine dysfunction following immune checkpoint inhibitor therapy

PURPOSE OF REVIEW

Immune checkpoint inhibitors (ICI) represent an important milestone in the modern era of antineoplastic therapy and have ushered optimism amongst oncologists and patients alike. These agents, however, are associated with significant potential toxicities, the importance of which cannot be overstated. The clinical presentation, diagnosis, and management strategies of immune-related endocrinopathies associated with ICI use are described in this case-based review.

RECENT FINDINGS

An increasing number of ICI have shown promise in the management of various malignancies in the recent years. These include cytotoxic T lymphocyte antigen-4 inhibitors, programmed cell death 1 (PD-1) antibodies, and PD-ligand 1 (PD-L1) antibodies. Several endocrinopathies, including hypophysitis, thyroid dysfunction, hyperglycemia, and primary adrenal insufficiency, have been associated with the use of these agents. Toxicities may range from mild transient laboratory abnormalities to potentially life-threatening ones, warranting immediate therapeutic intervention. Combination ICI therapies may be associated with a greater risk of endocrine dysfunction when compared with monotherapy. The clinical presentation and laboratory assessment of these patients often pose a diagnostic challenge as they may be confused by the symptoms related to their underlying malignancy or potential associated acute illnesses.

SUMMARY

ICI use is associated with serious endocrinopathies that may have a nonspecific initial presentation. A constant eye for these symptoms and a systematic approach to diagnosis are essential for prompt initiation of therapy and prevention of significant complications.

Anti-thyroglobulin antibodies do not significantly increase the risk of finding iodine avid metastases on post-radioactive iodine ablation scan in low-risk thyroid cancer patients

OBJECTIVE

Post-operative thyroglobulin (Tg) levels can predict the likelihood of residual cancer, including distant metastases, thereby influencing postsurgical treatment strategies even in patients with low-risk disease. Circulating anti-thyroglobulin antibodies (anti-Tg Abs) interfere with Tg measurement preventing this clinical use. It is not known if the presence of anti-Tg Abs predicts metastatic disease on post-therapy scan in patients with low-risk disease or if they should influence the use or dose of I-131 therapy. In the present study, we compare post-therapy scans in low-risk patients with and without anti-Tg Abs.

METHODS

This is a single-institution retrospective study. The study population (Group A) included all patients with low-risk differentiated thyroid cancer (DTC) who underwent total thyroidectomy and RAI between 1/1/2006 to 9/11/2015 with intrathyroidal T1-T2, Nx, N0 or N1a (≤5 nodes all measuring, when reported, <2 mm) that had anti-thyroglobulin antibodies. Patients were excluded if they had known distant metastases and/or extensive vascular invasion. A second group of patients (Group B) treated during the same period but without anti-Tg antibodies was selected to match group A by propensity core matching with a logistic regression model.

RESULTS

Each group included 37 patients. In group A: Median age was 40 years, 86% female and 76% PTC. Median tumor size was 2 cm (0.2-3.8), 32% had multifocal disease, 16% were N1a and 4% had vascular invasion. Parameters in group B were not statistically different from Group A, as expected based on the selection criteria, except being less likely to have Hashimoto's thyroiditis on pathology (p < 0.001). Post-therapy scan results were compared by Chi-square test with 86% negative post therapy scan frequency in group A and 92% in group B without evidence of a difference (p = 0.45).

CONCLUSION

In patients with low-risk DTC, anti-Tg Abs did not significantly predict metastatic disease on post-therapy scan. If confirmed, these data suggest that the presence of anti-Tg Abs alone should not influence initial therapy in patients with low-risk DTC.

Thyroid nodules and cancer management guidelines: comparisons and controversies

Thyroid cancer is an increasingly prevalent malignancy throughout the world. Management guidelines for both thyroid nodules and thyroid cancer have been published and updated by a number of societies internationally. All of these guidelines recognize this increasing incidence, particularly of small papillary thyroid cancers, due in part to improved technology enabling early or even 'over' diagnosis. Recent advances in molecular imaging and molecular methods have been developed to better characterize thyroid nodules, and a number of studies that have clarified risk stratification systems that can be modified over time allow for individualization of diagnosis, initial treatment, and subsequent follow-up strategies. Advances in surgical approaches and new treatments for patients with the most aggressive forms of thyroid cancer have all influenced management guidelines. Despite substantial similarities, there also are important differences between recent guidelines for some of the common clinical scenarios encountered by physicians in clinical practice. In the present manuscript, we will highlight similarities and differences between several of the most recently published guidelines focused on key areas of importance to clinical care and controversy. These are key areas for future research to strengthen the data to support future guideline recommendations.

Thyroglobulin Liquid Chromatography-Tandem Mass Spectrometry Has a Low Sensitivity for Detecting Structural Disease in Patients with Antithyroglobulin Antibodies

BACKGROUND

Thyroglobulin (Tg) measurement in patients with positive antithyroglobulin antibodies (anti-TgAbs) is not reliable. Tg measurement using liquid chromatography-tandem mass spectrometry (LC/MS) may be useful in this setting.

METHODS

This is a retrospective study with the objective of determining the accuracy of Tg-LC/MS in patients with thyroid cancer with anti-TgAbs. All patients with follicular cell-derived thyroid cancer (TC) who had thyroglobulin measured using LC/MS assay from November 1, 2013, to November 7, 2014, were evaluated. The frequency of detectable Tg-LC/MS was evaluated, with a functional sensitivity (FS) of 0.5 ng/mL in patients with structural disease. Then performance of Tg-LC/MS versus Tg immunometric assay (IMA) was compared using either Immulite assay (Tg-1) with a FS of 0.9 ng/mL or Beckman assay (Tg-B) with a FS of 0.1 ng/mL in detecting structural disease in patients with positive anti-TgAbs.

RESULTS

A total of 154 consecutive patients were included in this evaluation. Of these, 116 (75%) patients were positive for anti-TgAbs. In patients with structural disease and positive anti-TgAbs, Tg-LC/MS was undetectable in 43.7% of patients. Then the diagnostic accuracy for structural disease of Tg-LC/MS was compared with each Tg-IMA assay separately. In the 26 patients with positive anti-TgAbs where a Tg-I assay was used, the sensitivity and specificity for detecting structural disease were 33.3% and 88.2%, respectively, for the Tg-I assay, and 44.4% and 94.1%, respectively, for the Tg-LC/MS assay. In the 74 patients with positive anti-TgAbs where Tg-B was used, the sensitivity and specificity for detection of structural disease were 72.7% and 71.4%, respectively, for the Tg-B assay, and 62.6% and 93.7%, respectively, for the Tg-LC/MS assay.

CONCLUSION

In patients with thyroid cancer with positive anti-TgAbs, Tg-LC/MS was frequently undetectable and was less sensitive for detecting disease than a Tg assay was with a functional sensitivity of 0.1 ng/mL. For patients with detectable Tg-LC/MS and anti-TgAbs, use of the assay for monitoring requires further prospective studies.

Papillary Thyroid Carcinoma: Association Between Germline DNA Variant Markers and Clinical Parameters

BACKGROUND

Papillary thyroid cancer (PTC) is reported to be highly heritable in epidemiological studies. Genome-wide association studies (GWAS) have uncovered several variants associated with PTC predisposition. It remains unknown whether these variants might contribute to better clinical stratification of PTC patients.

METHODS

In order to assess the usefulness of germline genetic analyses in the management of PTC patients, the genotypes of five variants (rs965513, rs944289, rs116909374, rs2439302, and rs966423) were determined in 1216 PTC patients and 1416 controls. Additionally, the expression of seven genes located close to GWAS variants (PTCSC3, MBIP, NKX2-1, FOXE1, DIRC3, PTCSC2, and NRG1) were measured in 73 PTC paired tumor/normal tissues, respectively. Next, the association was analyzed between the genotypes of the germline variants and the levels of gene expression with clinical/pathological features such as age, sex, TNM staging, multifocality status, extrathyroidal expansion, and MACIS score.

RESULTS

The risk allele of rs965513 was associated with larger tumor size (p = 0.025) and extrathyroidal expansion (odd ratio [OR] = 1.29, p = 0.045). The variant rs2439302 showed association with lymph node metastasis (OR = 1.24, p = 0.016), and multifocality status of the tumor (OR = 1.24, p = 0.012). The expression of MBIP was associated with T stage (p = 0.010). MBIP and PTCSC3 displayed lower expression in PTC tissue in males than in females (p = 0.025 and p = 0.036, respectively). NKX2-1 displayed lower expression in patients with N1 stage (p = 0.040).

CONCLUSIONS

The studied germline risk alleles predisposing to PTC were associated with a more aggressive course of the disease reflected by larger tumor diameter, higher multifocality rate, and more advanced N stage at the time of diagnosis. These results show that germline variants not only predispose to PTC but also might impact its clinical course. However, these associations were only moderate, and further large multi-ethnic studies are required to evaluate the usefulness of these germline variants in the clinical stratification of PTC patients.

Multicenter clinical experience with the Afirma gene expression classifier

BACKGROUND

Increasingly, patients with thyroid nodule cytology labeled atypical (or follicular lesion) of undetermined significance (AUS/FLUS) or follicular neoplasm (FN) undergo diagnostic analysis with the Afirma gene expression classifier (GEC). No long-term, multisite analysis of Afirma GEC performance has yet been performed.

METHODS

We analyzed all patients who had received Afirma GEC testing at five academic medical centers between 2010 and 2013. Nodule and patient characteristics, fine needle aspiration cytology, Afirma GEC results, and subsequent clinical or surgical follow-up were obtained for 339 patients. Results were analyzed for pooled test performance, impact on clinical care, and site-to-site variation.

RESULTS

Three hundred thirty-nine patients underwent Afirma GEC testing of cytologically indeterminate nodules (165 AUS/FLUS; 161 FN; 13 suspicious for malignancy) and 174 of 339 (51%) indeterminate nodules were GEC benign, whereas 148 GEC were suspicious (44%). GEC results significantly altered care recommendations, as 4 of 175 GEC benign were recommended for surgery in comparison to 141 of 149 GEC suspicious (P<.01). Of 121 Cyto Indeterminate/GEC Suspicious nodules surgically removed, 53 (44%) were malignant. Variability in site-to-site GEC performance was confirmed, as the proportion of GEC benign varied up to 29% (P=.58), whereas the malignancy rate in nodules cytologically indeterminate/GEC suspicious varied up to 47% (P=.11). Seventy-one of 174 GEC benign nodules had documented clinical follow-up for an average of 8.5 months, in which 1 of 71 nodules proved cancerous.

CONCLUSIONS

These multicenter, clinical experience data confirm originally published Afirma GEC test performance and demonstrate its substantial impact on clinical care recommendations. Although nonsignificant site-to-site variation exists, such differences should be anticipated by the practicing clinician. Follow-up of GEC benign nodules thus far confirm the clinical utility of this diagnostic test.

Approach to follow-up of the patient with differentiated thyroid cancer and positive anti-thyroglobulin antibodies

Anti-thyroglobulin antibodies are commonly identified in patients with differentiated follicular cell-derived thyroid cancer. When present, they interfere with the measurement of thyroglobulin (Tg), which is the primary biochemical marker used for disease surveillance, creating challenges in monitoring patients for residual or recurrent disease. Moreover, there is variability in measuring anti-Tg antibodies according to the different assays, such that not all patients with anti-Tg antibodies are identifiable on a single assay system. The persistence of anti-Tg antibodies, especially if levels are rising, may indicate persistent, recurrent, or progressive thyroid cancer. In contrast, declining anti-Tg antibody levels may indicate reduced tumor burden or the absence of disease. In this review, we will explore in a case-based manner the data supporting monitoring and treatment paradigms for patients with anti-Tg antibodies and will stress areas where more evidence is needed to better inform clinicians regarding the management of patients with this challenging situation.

Analytic bias among certified methods for the measurement of hemoglobin A1c: a cause for concern?

We studied the magnitude, significance, and origin of an analytic bias that emerged between our point-of-care (POC) and our central laboratory (CL) methods for the measurement of hemoglobin A1c (HbA1c) and evaluated the analytic accuracy of 7 commonly used HbA1c methods relative to the National Glycohemoglobin Standardization Program (NGSP) reference method. The POC and CL methods were compared by split-sample analysis of clinical specimens and time series analyses of the HbA1c results reported for a 33-month period. The relative accuracies of 7 HbA1c methods were evaluated using College of American Pathologists proficiency survey results. Long-term drifts in the CL- and POC-analyzed test results caused the median intermethod bias [(POC result)-(CL result)] to increase from -0.4% to -0.9% HbA1c. Systematic biases, drifts in analytic performance over time, and intermethod variability were frequently observed among the 7 NGSP-certified HbA1c methods. Intermethod variability is a potential source of inaccuracy whenever HbA1c results are interpreted relative to universal, fixed, clinical decision thresholds.

Latent autoimmune diabetes of adulthood. Unique features that distinguish it from types 1 and 2

A number of patients with poor glycemic control receive the diagnosis of type 2 diabetes despite the fact that they do not exhibit some of the traditional characteristics of the disease, such as obesity. A more accurate diagnosis for many of these patients is latent autoimmune diabetes of adulthood (LADA). In this article, Dr Nabhan and coauthors describe features that LADA has in common with type 1 and type 2 diabetes, as well as those that distinguish LADA from these more widely recognized forms of diabetes. The authors also describe the pathogenesis of the disease, potential complications, and treatment options.