Excellent Response to Therapy Occurs for Most Patients With Thyroid Cancer Treated With Lobectomy.

INTRODUCTION: American Thyroid Association (ATA) Guidelines for Management of Thyroid Nodules and Thyroid Cancer indicate that thyroid lobectomy (TL) or total thyroidectomy (TT) are appropriate surgery for low- and intermediate-risk well-differentiated thyroid carcinoma. We sought to determine outcomes of TL or TT by ATA response to therapy (RTT) classification. METHODS: This is a single-institution retrospective cohort study of adults with unilateral suspicious or malignant thyroid nodules under 4 cm from January 2016 through December 2021. Our primary outcome was ATA RTT. RESULTS: During the study period, 118 met inclusion criteria: 37 (31%) underwent TL and 81 (69%) TT. Of the TL patients, 7 (19%) underwent completion thyroidectomy. Response to therapy (RTT) was similar with TT versus TL: excellent response 56 (69%) versus 30 (81%), indeterminate response 20 (25%) versus 5 (14%), and biochemically incomplete response 5 (6%) versus 2 (5%), P = 0.20. There were no differences between the groups for age, sex, race or ethnicity, tumor size, histologic type, or complications. Thyroidectomy (TT) was associated with multiple nodules 47% versus 22% for TL (P = 0.009), bilateral nodules 43% versus 16% (P = 0.004), central neck lymph nodes removed median 3 (interquartile range [IQR] 1-8) versus 0 (IQR 0-2) P < 0.001, lymph node metastases median 0 (IQR 0-1) versus 0 (0-0) P = 0.02. Median follow-up was 32.5 mo (IQR 17-56 mo) and was similar between the groups. CONCLUSIONS: Patients with TL for well-differentiated thyroid carcinoma without high-risk features have an RTT similar to patients undergoing TT. In this cohort, 81% of patients treated with TL have not required additional intervention.

Endocrinopathies Associated With Immune Checkpoint Inhibitor Use.

OBJECTIVE: To provide a clinical approach towards immune checkpoint inhibitor (ICI)-associated endocrinopathies, their link with cancer outcomes, factors which differentiate them from other immune related adverse events, and health systems innovation to improve care for these patients. METHODS: A literature search for articles pertaining to ICIs and endocrinopathies was performed and supplemented by expert opinions of the authors. RESULTS: While immune related adverse events can affect almost any organ, they frequently target the endocrine glands, most commonly thyroid. Different classes of ICIs have varying frequencies of endocrinopathies related to hypophysitis, thyroiditis, diabetes mellitus, and rarely hypoadrenalism and hypoparathyroidism. ICI-associated endocrinopathies share some features with classic endocrine autoimmunity but appear to be a distinct entity. They can be challenging to diagnose and manage due to nonspecific clinical features, use of exogenous glucocorticoids, and at times rapid and severe hormone deficiency. The role of anti-inflammatory high-dose glucocorticoids is minimal, and the ICI does not usually require permanent discontinuation. ICI-associated endocrinopathies usually cause permanent hormone deficiency necessitating long-term management and patient engagement. ICI-thyroiditis has been associated with improved survival, while other endocrinopathies have not shown a significant association with outcomes in cancer patients receiving ICIs. Oncoendocrinology teams can improve the care of patients with ICI-associated endocrinopathies. CONCLUSION: This narrative review provides guidance to clinicians prescribing ICIs and those managing ICI-associated endocrinopathies, and complements the frameworks provided by major scientific societies in this field.

Thyroid Cancer Survivorship: Challenges and Opportunities.

OBJECTIVE: To provide a narrative review of challenges and opportunities in the care of thyroid cancer survivors. METHODS: A literature search for full-text articles pertaining to quality of life and survivorship in thyroid cancer was performed and supplemented with personal experience of the authors. RESULTS: Despite usually favorable prognosis for most thyroid cancer survivors, health-related quality of life (HRQOL) can be as poor or even worse than that in more aggressive cancers. Worry of cancer recurrence and long-term effects from cancer treatment adversely affects HRQOL in addition to other factors. Disparities and financial hardships among thyroid cancer survivors further affect HRQOL. In addition to monitoring for cancer recurrence and managing hypothyroidism, long-term effects from cancer treatment, including surgical complications, effects from radioactive iodine therapy, a small but increased risk of second primary malignancies, and aging-related health conditions (bone, cardiac, and fertility), need to be monitored for and addressed during survivorship care. CONCLUSION: Survivorship care models can vary depending on the specifics of the population served; however, a team-based survivor-centered approach provides the best care to thyroid cancer survivors.

Hypophysitis and Secondary Adrenal Insufficiency From Immune Checkpoint Inhibitors: Diagnostic Challenges and Link With Survival.

BACKGROUND: Hypophysitis is a serious adverse event stemming from immune checkpoint inhibitor (ICI) therapy for malignancy. This study aimed to characterize ICI-induced hypophysitis, identify diagnostic challenges, and evaluate an association with survival in a large cancer cohort. METHODS: We performed a retrospective cohort study of adult patients with cancer who received ICIs between December 1, 2012, and December 31, 2019. We identified 839 patients who received CTLA-4, PD-1, or PD-L1 inhibitors or a combination thereof who were followed for a median of 19.4 months. Hypophysitis was defined as MRI evidence of pituitary gland and/or stalk enlargement or biochemical evidence of hypopituitarism if not explained by another etiology. RESULTS: A total of 16 (1.9%) patients developed hypophysitis a median of 7 months after ICI initiation, with most patients having melanoma (9/16; 56.2%) or renal cell carcinoma (4/16; 25%). Two patients also had exogenous glucocorticoid exposure but exhibited secondary hypothyroidism and secondary adrenal insufficiency (AI). Median age at the start of ICI was 61.3 years and 57% were men. Patients who developed hypophysitis were younger compared with those who did not develop hypophysitis (median age, 57 vs 65 years; P=.011). Hypophysitis occurred most frequently after combination therapy (13.7%) compared with CTLA-4 monotherapy (1.9%), PD-1 monotherapy (1.2%), and PD-L1 monotherapy (0.8%) (P<.0001). Pituitary gland enlargement on MRI occurred more frequently after CTLA-4 inhibitor monotherapy or combination therapy (5/7; 71.4%) compared with PD-1/PD-L1 inhibitor monotherapy (1/6; 16.7%). The survival benefit of hypophysitis was not apparent after addressing immortal time bias and adjusting for other variables affecting patient outcomes. CONCLUSIONS: Secondary AI occurred in all patients, and secondary hypothyroidism occurred in half. Classic pituitary gland enlargement is usually absent in PD-1/PD-L1 inhibitor-induced hypophysitis. Further pituitary evaluation must be conducted to differentiate secondary AI resulting from exogenous glucocorticoids and hypophysitis in patients with cancer receiving ICIs. The link between hypophysitis and ICI efficacy needs further investigation.

Thyroid Carcinoma, Version 2.2022, NCCN Clinical Practice Guidelines in Oncology.

Differentiated thyroid carcinomas is associated with an excellent prognosis. The treatment of choice for differentiated thyroid carcinoma is surgery, followed by radioactive iodine ablation (iodine-131) in select patients and thyroxine therapy in most patients. Surgery is also the main treatment for medullary thyroid carcinoma, and kinase inhibitors may be appropriate for select patients with recurrent or persistent disease that is not resectable. Anaplastic thyroid carcinoma is almost uniformly lethal, and iodine-131 imaging and radioactive iodine cannot be used. When systemic therapy is indicated, targeted therapy options are preferred. This article describes NCCN recommendations regarding management of medullary thyroid carcinoma and anaplastic thyroid carcinoma, and surgical management of differentiated thyroid carcinoma (papillary, follicular, Hürthle cell carcinoma).

Neuroendocrine and Adrenal Tumors, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology.

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Neuroendocrine and Adrenal Gland Tumors focus on the diagnosis, treatment, and management of patients with neuroendocrine tumors (NETs), adrenal tumors, pheochromocytomas, paragangliomas, and multiple endocrine neoplasia. NETs are generally subclassified by site of origin, stage, and histologic characteristics. Appropriate diagnosis and treatment of NETs often involves collaboration between specialists in multiple disciplines, using specific biochemical, radiologic, and surgical methods. Specialists include pathologists, endocrinologists, radiologists (including nuclear medicine specialists), and medical, radiation, and surgical oncologists. These guidelines discuss the diagnosis and management of both sporadic and hereditary neuroendocrine and adrenal tumors and are intended to assist with clinical decision-making. This article is focused on the 2021 NCCN Guidelines principles of genetic risk assessment and counseling and recommendations for well-differentiated grade 3 NETs, poorly differentiated neuroendocrine carcinomas, adrenal tumors, pheochromocytomas, and paragangliomas.

Patient Reported Outcome Measures of Health-Related Quality of Life and Asthenia after Thyroidectomy.

BACKGROUND: After thyroidectomy some patients experience a chronic fatigue syndrome called asthenia. The purpose of this study was to determine the post-operative health related quality of life (HRQOL) and risk of asthenia in patients undergoing thyroidectomy. METHODS: A single institution prospective observational cohort study of adults undergoing thyroidectomy from September 2016 to July 2019 with four HRQOL surveys: preoperative baseline, 2 wk-, 6 mo- and 12 mo-postoperatively. Patients were surveyed using the Short Form 36 version 2 and Brief Fatigue Inventory. Asthenia was defined as Brief Fatigue Inventory > 60 at 12 mo. HRQOL was compared between patients undergoing thyroid lobectomy (TL) or total thyroidectomy (TT) with benign (-B) or malignant (-Ca) final pathology. RESULTS: A total of 182 patients were included: 67 (37%) with TL-B, 32 (17%) with TL-Ca, 40 (22%) with TT-B, and 43 (24%) with TT-Ca. The incidence of asthenia was 42% for TT and 4% for TL. In the TL-B group, 2 patients (3%) developed asthenia, compared with 2 patients (6.25%) in the TL-Ca group, 14 patients (35%) in the TT-B group, and 21 (48.8%) in the TT-Ca group (P = 0.0001). The odds ratio of asthenia for TT compared to TL was 10.4 (95% CI 3.86-28.16) and for patients with malignancy compared to benign disease was 2.05 (95% CI 1.17-3.61). CONCLUSIONS: Patients undergoing TT have a higher risk of developing asthenia than those undergoing TL, particularly if the final pathology shows malignancy.

The Association of Diabetes and Hyperglycemia on Inpatient Readmissions.

OBJECTIVE: To evaluate the association between inpatient glycemic control and readmission in individuals with diabetes and hyperglycemia (DM/HG). METHODS: Two data sets were analyzed from fiscal years 2011 to 2013: hospital data using the International Classification of Diseases, Ninth Revision (ICD-9) codes for DM/HG and point of care (POC) glucose monitoring. The variables analyzed included gender, age, mean, minimum and maximum glucose, along with 4 measures of glycemic variability (GV), standard deviation, coefficient of variation, mean amplitude of glucose excursions, and average daily risk range. RESULTS: Of 66 518 discharges in FY 2011-2013, 28.4% had DM/HG based on ICD-9 codes and 53% received POC monitoring. The overall readmission rate was 13.9%, although the rates for individuals with DM/HG were higher at 18.9% and 20.6% using ICD-9 codes and POC data, respectively. The readmitted group had higher mean glucose (169 ± 47 mg/dL vs 158 ± 46 mg/dL, P < .001). Individuals with severe hypoglycemia and hyperglycemia had the highest readmission rates. All 4 GV measures were consistent and higher in the readmitted group. CONCLUSION: Individuals with DM/HG have higher 30-day readmission rates than those without. Those readmitted had higher mean glucose, more extreme glucose values, and higher GV. To our knowledge, this is the first report of multiple metrics of inpatient glycemic control, including GV, and their associations with readmission.

MnTnBuOE-2-PyP treatment protects from radioactive iodine (I-131) treatment-related side effects in thyroid cancer.

Treatment of differentiated thyroid cancer often involves administration of radioactive iodine (I-131) for remnant ablation or adjuvant therapy. However, there is morbidity associated with I-131 therapy, which can result in both acute and chronic complications. Currently, there are no approved radioprotectors that can be used in conjunction with I-131 to reduce complications in thyroid cancer therapy. It is well known that the damaging effects of ionizing radiation are mediated, in part, by the formation of reactive oxygen species (ROS). A potent scavenger of ROS, Mn(III)meso-tetrakis(N-n-butoxyethylpyridinium-2-yl)porphyrin (MnTnBuOE-2-PyP), has radioprotective and anti-tumor effects in various cancer models including head and neck, prostate, and brain tumors exposed to external beam radiation therapy. Female C57BL/6 mice were administered I-131 orally at doses of 0.0085-0.01 mCi/g (3.145 × 105 to 3.7 × 105 Bq) of body weight with or without MnTnBuOE-2-PyP. We measured acute external inflammation, blood cell counts, and collected thyroid tissue and salivary glands for histological examination. We found oral administration of I-131 caused an acute decrease in platelets and white blood cells, caused facial swelling, and loss of thyroid and salivary tissues. However, when MnTnBuOE-2-PyP was given during and after I-131 administration, blood cell counts remained in the normal range, less facial inflammation was observed, and the salivary glands were protected from radiation-induced killing. These data indicate that MnTnBuOE-2-PyP may be a potent radioprotector of salivary glands in thyroid cancer patients receiving I-131 therapy.

Hemithyroidectomy for Thyroid Cancer: A Review.

Thyroid cancer incidence is on the rise; however, fortunately, the death rate is stable. Most persons with well-differentiated thyroid cancer have a low risk of recurrence at the time of diagnosis and can expect a normal life expectancy. Over the last two decades, guidelines have recommended less aggressive therapy for low-risk cancer and a more personalized approach to treatment of thyroid cancer overall. The American Thyroid Association (ATA) and National Comprehensive Cancer Network (NCCN) thyroid cancer guidelines recommend hemithyroidectomy as an acceptable surgical treatment option for low-risk thyroid cancer. Given this change in treatment paradigms, an increasing number of people are undergoing hemithyroidectomy rather than total or near-total thyroidectomy as their primary surgical treatment of thyroid cancer. The postoperative follow-up of hemithyroidectomy patients differs from those who have undergone total or near-total thyroidectomy, and the long-term monitoring with imaging and biomarkers can also be different. This article reviews indications for hemithyroidectomy, as well as postoperative considerations and management recommendations for those who have undergone hemithyroidectomy.

Pesticide use and incident hyperthyroidism in farmers in the Agricultural Health Study.

BACKGROUND: Few studies have evaluated associations between pesticides and hyperthyroidism. OBJECTIVE: We evaluated associations between specific pesticides and incident hyperthyroidism in private pesticide applicators in the Agricultural Health Study. METHODS: We used Cox proportional hazards models to estimate HRs and 95% CIs for associations between pesticide use at enrolment and hyperthyroidism (n=271) in 35 150 applicators (mostly men), adjusting for potential confounders. RESULTS: Ever use of several pesticides (organophosphate insecticide malathion, fungicide maneb/mancozeb, herbicides dicamba, metolachlor, and atrazine in overall sample and chlorimuron ethyl among those ≤62 years) was associated with reduced hyperthyroidism risk, with HRs ranging from 0.50 (95% CI 0.30 to 0.83) for maneb/mancozeb to 0.77 (95% CI 0.59 to 1.00) for atrazine. Hyperthyroidism risk was lowest among those with higher intensity-weighted lifetime days of using carbofuran and chlorpyrifos (ptrend ≤0.05). CONCLUSIONS: Observed associations between pesticides and decreased risk of hyperthyroidism warrant further investigation.

NCCN Guidelines Insights: Thyroid Carcinoma, Version 2.2018.

The NCCN Guidelines for Thyroid Carcinoma provide recommendations for the management of different types of thyroid carcinoma, including papillary, follicular, Hürthle cell, medullary, and anaplastic carcinomas. These NCCN Guidelines Insights summarize the panel discussion behind recent updates to the guidelines, including the expanding role of molecular testing for differentiated thyroid carcinoma, implications of the new pathologic diagnosis of noninvasive follicular thyroid neoplasm with papillary-like nuclear features, and the addition of a new targeted therapy option for BRAF V600E-mutated anaplastic thyroid carcinoma.

NCCN Guidelines Insights: Neuroendocrine and Adrenal Tumors, Version 2.2018.

The NCCN Guidelines for Neuroendocrine and Adrenal Tumors provide recommendations for the management of adult patients with neuroendocrine tumors (NETs), adrenal gland tumors, pheochromocytomas, and paragangliomas. Management of NETs relies heavily on the site of the primary NET. These NCCN Guidelines Insights summarize the management options and the 2018 updates to the guidelines for locoregional advanced disease, and/or distant metastasis originating from gastrointestinal tract, bronchopulmonary, and thymus primary NETs.

Management of the hospitalized transplant patient.

Significant hyperglycemia is commonly observed immediately after solid organ and bone marrow transplant as well as with subsequent hospitalizations. Surgery and procedures are well known to cause pain and stress leading to secretion of cytokines and other hormones known to aggravate insulin action. Immunosuppression required for transplant and preexisting risk are also major factors. Glucose control improves outcomes for all hospitalized patients, including transplant patients, but is often more challenging to achieve because of frequent and sometimes unpredictable changes in immunosuppression doses, renal function, and nutrition. As a result, risk of hypoglycemia can be greater in this patient group when trying to achieve glucose control goals for hospitalized patients. Key to successful management of hyperglycemia is regular communication between the members of the care team as well as anticipating and rapidly implementing a new treatment paradigm in response to changes in immunosuppression, nutrition, renal function, or evidence of changing insulin resistance.

Neuroendocrine tumors, version 1.2015.

Neuroendocrine tumors (NETs) comprise a broad family of tumors that may or may not be associated with symptoms attributable to hormonal hypersecretion. The NCCN Clinical Practice Guidelines in Oncology for Neuroendocrine Tumors discuss the diagnosis and management of both sporadic and hereditary NETs. This selection from the guidelines focuses on sporadic NETs of the pancreas, gastrointestinal tract, lung, and thymus.

Inpatient hypoglycemia: a challenge that must be addressed.

Hypoglycemia in the inpatient setting is a common occurrence with potentially harmful outcomes. Large trials in both the inpatient and outpatient settings have found a correlation between hypoglycemia and morbidity and mortality. The incidence of hypoglycemia is difficult to assess, due to a lack of standardized definitions and different methods of data collection between hospital systems. Risk factors that predispose to hypoglycemia involve the changing clinical statuses of patients, nutrition issues, and hospital processes. Mechanisms contributing to morbidity due to hypoglycemia may include an increase in sympathoadrenal responses, as well as indirect changes affecting cytokine production, coagulation, fibrinolysis, and endothelial function. Prevention of hypoglycemia requires implementation of several strategies that include patient safety, quality control, multidisciplinary communication, and transitions of care. In this article, we discuss all of these issues and provide suggestions to help predict and prevent hypoglycemic episodes during an inpatient stay. We address the issues that occur upon admission, during the hospital stay, and around the time of discharge. We believe that decreasing the incidence of inpatient hypoglycemia will both decrease costs and improve patient outcomes.

Beneficial role for supplemental vitamin D3 treatment in chronic urticaria: a randomized study.

BACKGROUND: Observational reports have linked vitamin D with chronic urticaria, yet no randomized controlled trial has been conducted. OBJECTIVE: To determine whether high-dose vitamin D supplementation would decrease Urticaria Symptom Severity (USS) scores and medication burden in patients with chronic urticaria. METHODS: In a prospective, double-blinded, single-center study, 42 subjects with chronic urticaria were randomized to high (4,000 IU/d) or low (600 IU/d) vitamin D3 supplementation for 12 weeks. All subjects were provided with a standardized triple-drug therapy (cetirizine, ranitidine, and montelukast) and a written action plan. Data on USS scores, medication use, blood for 25-hydroxyvitamin D, and safety measurements were collected. RESULTS: Triple-drug therapy decreased total USS scores by 33% in the first week. There was a further significant decrease (40%) in total USS scores in the high, but not low, vitamin D3 treatment group by week 12. Compared with low treatment, the high treatment group demonstrated a trend (P = .052) toward lower total USS scores at week 12, which was driven by significant decreases in body distribution and number of days with hives. Beneficial trends for sleep quality and pruritus scores were observed with high vitamin D3. Serum 25-hydroxyvitamin D levels increased with high vitamin D3 supplementation, but there was no correlation between 25-hydroxyvitamin D levels and USS scores. There was no difference in allergy medication use between groups. No adverse events occurred. CONCLUSION: Add-on therapy with high-dose vitamin D3 (4,000 IU/d) could be considered a safe and potentially beneficial immunomodulator in patients with chronic urticaria. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01371877.

Disparities in Thyroid Cancer Diagnosis Based on Residence and Distance From Medical Facility.

Context: Rural-urban disparities have been reported in cancer care, but data are sparse on the effect of geography and location of residence on access to care in thyroid cancer. Objective: To identify impact of rural or urban residence and distance from treatment center on thyroid cancer stage at diagnosis. Methods: We evaluated 800 adults with differentiated thyroid cancer in the iCaRe2 bioinformatics/biospecimen registry at the Fred and Pamela Buffett Cancer Center. Participants were categorized into early and late stage using AJCC staging, and residence/distance from treating facility was categorized as short (≤ 12.5 miles), intermediate (> 12.5 to < 50 miles) or long (≥ 50 miles). Multivariable logistic regression was used to identify factors associated with late-stage diagnosis. Results: Overall, 71% lived in an urban area and 29% lived in a rural area. Distance from home to the treating facility was short for 224 (28%), intermediate for 231 (28.8%), and long for 345 (43.1%). All 224 (100%) short, 226 (97.8%) intermediate, and 120 (34.7%) long distances were for urban patients; in contrast, among rural patients, 5 (2.16%) lived intermediate and 225 (65.2%) lived long distances from treatment (P < .0001). Using eighth edition AJCC staging, the odds ratio of late stage at diagnosis for rural participants ≥ 55 years was 2.56 (95% CI, 1.08-6.14) (P = .03), and for those living ≥ 50 miles was 4.65 (95% CI, 1.28-16.93) (P = .0075). Results were similar using seventh edition AJCC staging. Conclusion: Older age at diagnosis, living in rural areas, and residing farther from the treatment center are all independently associated with late stage at diagnosis of thyroid cancer.

Outcomes of cytologically indeterminate thyroid nodules managed with Genomic Sequencing Classifier.

CONTEXT: Molecular testing can refine the risk of malignancy in thyroid nodules with indeterminate cytology to decrease unnecessary diagnostic surgery. OBJECTIVE: This study was performed to evaluate the outcomes of cytologically indeterminate thyroid nodules managed with Afirma genomic sequencing classifier (GSC) testing. DESIGN, SETTING, PATIENTS, AND INTERVENTION: Adult patients who underwent a biopsy at three major academic centers between July 2017 and June 2021 with Bethesda III or IV cytology were included. All patients had surgery or minimum follow-up of 1 year ultrasound surveillance. MAIN OUTCOME MEASURES: The primary outcomes were the sensitivity, specificity, PPV, and NPV of GSC in Bethesda III and IV nodules. RESULTS: The median nodule size of the 834 indeterminate nodules was 2.1 cm and the median follow-up was 23 months. GSC's sensitivity, specificity, PPV, and NPV across all institutions were 95%, 81%, 50%, and 99% for Bethesda III nodules and 94%, 82%, 65%, and 98% for Bethesda IV nodules, respectively. The overall false negative rate was 2%. The NPV of GSC in thyroid nodules with oncocytic predominance was 100% in Bethesda III nodules and 98% in Bethesda IV nodules. However, the PPV of oncocytic nodules was low (17% in Bethesda III nodules and 45% in Bethesda IV nodules). Only 22% of thyroid nodules with benign GSC results grew during surveillance. CONCLUSIONS: GSC is a key tool for managing patients with indeterminate cytology, including the higher-risk Bethesda IV category. GSC benign thyroid nodules can be observed similarly to thyroid nodules with benign cytology.

Relaxin-2 is a novel biomarker for differentiated thyroid carcinoma in humans.

Relaxin's role in differentiated thyroid cancer (DTC) has been suggested but its characterization in a large clinical sample remains limited. We performed immunohistochemistry for relaxin-2 (RLN2), CD68 (total macrophages), CD163 (M2 macrophages) on tissue microarrays from 181 subjects with non-distant metastatic DTC, and 185 subjects with benign thyroid tissue. Mean pixels/area for each marker was compared between tumor and adjacent tissue via paired-t test and between DTC and benign subjects via t-test assuming unequal variances. RNA qPCR was performed for expression of RLN2, RLN1, and RXFP1 in cell lines. Amongst 181 cases, the mean age was 46 years, 75 % were females. Tumoral tissue amongst the DTC cases demonstrated higher mean expression of RLN2 (53.04 vs. 9.79; p < 0.0001) compared to tumor-adjacent tissue. DTC tissue also demonstrated higher mean expression of CD68 (14.46 vs. 4.79; p < 0.0001), and CD163 (23.13 vs. -0.73; p < 0.0001) than benign thyroid. These markers did not differ between tumor-adjacent and benign thyroid tissue groups; and amongst cases, did not differ by demographic or clinicopathologic features. RLN1 and RXFP1 expression was detected in a minority of the cell lines, while RLN2 was expressed by 6/7 cell lines. In conclusion, widespread RLN2 expression in DTC tissue and most cell lines demonstrates that RLN2 acts in a paracrine manner, and that RLN1 and RXFP1 are probably not involved in thyroid cancer cell signaling. RLN2 is a biomarker for thyroid carcinogenesis, being associated with but not secreted by immunosuppressive macrophages. These findings will guide further investigations for therapeutic avenues against thyroid cancer.