Computer-Assisted Levothyroxine Dose Selection for the Treatment of Postoperative Hypothyroidism.

Background: Thyroid hormone replacement with levothyroxine (LT4) is a recommended treatment for patients undergoing thyroidectomy. The starting LT4 dose is frequently calculated based on the patient's weight. However, the weight-based LT4 dosing performs poorly in clinical practice, with only ∼30% of patients achieving target thyrotropin (TSH) levels at the first thyroid function testing after treatment initiation. A better way to calculate the LT4 dose for patients with postoperative hypothyroidism is needed. Methods: In this retrospective cohort study we used demographic, clinical, and laboratory data for 951 patients after thyroidectomy and several regression and classification machine learning methods to develop an LT4 dose calculator for treating postoperative hypothyroidism targeting the desired TSH level. We compared the accuracy with the current standard-of-care practice and other published algorithms and evaluated generalizability with fivefold cross-validation and out-of-sample testing. Results: The retrospective clinical chart review showed that only 285/951 (30%) patients met their postoperative TSH goal. Obese patients were overtreated with LT4. An ordinary least squares regression based on weight, height, age, sex, calcium supplementation, and height:sex interaction predicted prescribed LT4 dose in 43.5% of all patients and 45.3% of patients with normal postoperative TSH (0.45-4.5 mIU/L). The ordinal logistic regression, artificial neural networks regression/classification, and random forest methods achieved comparable performance. LT4 calculator recommended lower LT4 doses to obese patients. Conclusions: The standard-of-care LT4 dosing does not achieve the target TSH in most thyroidectomy patients. Computer-assisted LT4 dose calculation performs better by considering multiple relevant patient characteristics and providing personalized and equitable care to patients with postoperative hypothyroidism. Prospective validation of LT4 calculator performance in patients with various TSH goals is needed.

Mastermind Like Transcriptional Coactivator 3 (MAML3) Drives Neuroendocrine Tumor Progression.

Metastatic disease in pheochromocytomas and paragangliomas (PCC/PGL) is not well-understood. The Cancer Genome Atlas discovered recurrent MAML3 fusion genes in a subset of tumors that lacked known germline or somatic driver mutations and were associated with aggressive disease. Here, we aimed to investigate the role of MAML3 in tumorigenesis. Human PCC/PGLs were used for IHC and genetic analysis. Three neuroendocrine tumor cell lines, SK-N-SH, QGP-1, and BON-1, were transiently transfected with MAML3 (FL) or exon 1 deleted MAML3 (dEx1; mimicking the fusion), and biologic effects of overexpression were examined in vitro. We found 7% (4/55) of human PCC/PGL have UBTF∼MAML3 fusions and all were sporadic cases with metastatic disease. Fusion-positive tumors had intense MAML3 nuclear staining and increased ß-catenin by IHC and showed increased WNT4 expression. In vitro, overexpression of FL and dEx1 MAML3 increased invasion in SK-N-SH, QGP-1, and BON-1 (all P < 0.05) and increased soft-agar colony formation in QGP-1 and BON-1 (all P < 0.05). Cotransfection with FL or dEx1 MAML3 and ß-catenin increased TCF/LEF promoter activation by luciferase activity and coimmunoprecipitation confirmed interaction between MAML3 and ß-catenin. These data suggest MAML3 is involved in WNT signaling pathway activation. In summary, UBTF∼MAML3 fusions are present in a subset of PCC/PGL and associated with metastatic disease without other known drivers. MAML3 overexpression led to increased tumorigenicity in neuroendocrine tumor cells and the mechanism of action may involve WNT signaling pathways. IMPLICATIONS: MAML3 increases tumorigenicity and invasion in neuroendocrine tumor cells and may be a prognostic marker for aggressive disease.

Response to Immunotherapy in Combination With Mitotane in Patients With Metastatic Adrenocortical Cancer.

Adrenocortical carcinoma (ACC) is a rare orphan disease with a dismal prognosis. Surgery remains the first-line treatment, but most patients eventually develop metastatic disease. Mitotane is often used with chemotherapy with modest success. Little information is available concerning the efficacy of immunotherapy in combination with mitotane. We conducted a retrospective review of our initial six patients with metastatic ACC, for whom mitotane alone or with chemotherapy failed, and who were subsequently treated with a combination of pembrolizumab and mitotane, between July 2016 and March 2019. Imaging was analyzed per Response Evaluation Criteria in Solid Tumours 1.1 criteria. Two patients had a partial response and four patients had stable disease (8 to 19 months). One patient had grade 3 hepatitis and pembrolizumab was discontinued after 8 months. She died with disease progression 16 months after initiating pembrolizumab. One patient developed brain metastasis after 19 months of treatment and was transitioned to hospice. One patient had focal pneumonitis after 18 months of treatment, and pembrolizumab was discontinued. Three remaining patients continue pembrolizumab plus mitotane at the time of this writing. The current standard of care for ACC is a combination of etoposide, doxorubicin, cisplatin, and mitotane with an overall survival of 14.8 months. All six patients lived for at least 16 months after starting pembrolizumab added to mitotane therapy. The therapy appeared to be effective in both microsatellite instability-high and microsatellite stable tumors, suggesting some synergistic effect with mitotane. Combined immunotherapy and mitotane should be considered in future clinical trials in patients with ACC.

Establishment and Characterization of Four Novel Thyroid Cancer Cell Lines and PDX Models Expressing the RET/PTC1 Rearrangement, BRAFV600E, or RASQ61R as Drivers.

Cancer cell lines are critical models to study tumor progression and response to therapy. In 2008, we showed that approximately 50% of thyroid cancer cell lines were redundant or not of thyroid cancer origin. We therefore generated new authenticated thyroid cancer cell lines and patient-derived xenograft (PDX) models using in vitro and feeder cell approaches, and characterized these models in vitro and in vivo. We developed four thyroid cancer cell lines, two derived from 2 different patients with papillary thyroid cancer (PTC) pleural effusions, CUTC5, and CUTC48; one derived from a patient with anaplastic thyroid cancer (ATC), CUTC60; and one derived from a patient with follicular thyroid cancer (FTC), CUTC61. One PDX model (CUTC60-PDX) was also developed. Short tandem repeat (STR) genotyping showed that each cell line and PDX is unique and match the original patient tissue. The CUTC5 and CUTC60 cells harbor the BRAF (V600E) mutation, the CUTC48 cell line expresses the RET/PTC1 rearrangement, and the CUTC61 cells have the HRAS (Q61R) mutation. Moderate to high levels of PAX8 and variable levels of NKX2-1 were detected in each cell line and PDX. The CUTC5 and CUTC60 cell lines form tumors in orthotopic and flank xenograft mouse models. IMPLICATIONS: We have developed the second RET/PTC1-expressing PTC-derived cell line in existence, which is a major advance in studying RET signaling. We have further linked all cell lines to the originating patients, providing a set of novel, authenticated thyroid cancer cell lines and PDX models to study advanced thyroid cancer.

Elucidating the Role of the Maternal Embryonic Leucine Zipper Kinase in Adrenocortical Carcinoma.

Adrenocortical carcinoma (ACC) is an aggressive cancer with a 5-year survival rate <35%. Mortality remains high due to lack of targeted therapies. Using bioinformatic analyses, we identified maternal embryonic leucine zipper kinase (MELK) as 4.1-fold overexpressed in ACC compared with normal adrenal samples. High MELK expression in human tumors correlated with shorter survival and with increased expression of genes involved in cell division and growth. We investigated the functional effects of MELK inhibition using newly developed ACC cell lines with variable MELK expression, CU-ACC1 and CU-ACC2, compared with H295R cells. In vitro treatment with the MELK inhibitor, OTSSP167, resulted in a dose-dependent decrease in rates of cell proliferation, colony formation, and cell survival, with relative sensitivity of each ACC cell line based upon the level of MELK overexpression. To confirm a MELK-specific antitumorigenic effect, MELK was inhibited in H295R cells via multiple short hairpin RNAs. MELK silencing resulted in 1.9-fold decrease in proliferation, and 3- to 10-fold decrease in colony formation in soft agar and clonogenicity assays, respectively. In addition, although MELK silencing had no effect on survival in normoxia, exposure to a hypoxia resulted in a sixfold and eightfold increase in apoptosis as assessed by caspase-3 activation and TUNEL, respectively. Together these data suggest that MELK is a modulator of tumor cell growth and survival in a hypoxic microenvironment in adrenal cancer cells and support future investigation of its role as a therapeutic kinase target in patients with ACC.

Development of new preclinical models to advance adrenocortical carcinoma research.

Adrenocortical cancer (ACC) is an orphan malignancy that results in heterogeneous clinical phenotypes and molecular genotypes. There are no curative treatments for this deadly cancer with 35% survival at five years. Our understanding of the underlying pathobiology and our ability to test novel therapeutic targets has been limited due to the lack of preclinical models. Here, we report the establishment of two new ACC cell lines and corresponding patient-derived xenograft (PDX) models. CU-ACC1 cell line and PDX were derived from a perinephric metastasis in a patient whose primary tumor secreted aldosterone. CU-ACC2 cell line and PDX were derived from a liver metastasis in a patient with Lynch syndrome. Short tandem repeat profiling confirmed consistent matches between human samples and models. Both exomic and RNA sequencing profiling were performed on the patient samples and the models, and hormonal secretion was evaluated in the new cell lines. RNA sequencing and immunohistochemistry confirmed the expression of adrenal cortex markers in the PDXs and human tumors. The new cell lines replicate two of the known genetic models of ACC. CU-ACC1 cells had a mutation in CTNNB1 and secreted cortisol but not aldosterone. CU-ACC2 cells had a TP53 mutation and loss of MSH2 consistent with the patient's known germline mutation causing Lynch syndrome. Both cell lines can be transfected and transduced with similar growth rates. These new preclinical models of ACC significantly advance the field by allowing investigation of underlying molecular mechanisms of ACC and the ability to test patient-specific therapeutic targets.

Examination of Nondesignated Preliminary Surgery Residents Recruited Since the Inception of Supplementary Offer and Acceptance Program: Lessons Learned From a Large Academic Program.

PURPOSE: The majority of surgery programs roster non-designated preliminary (NDP) residents. We and others have reported on the success of NDP resident mentoring with regard to categorical position placement. Lacking is a focus on the candidates themselves and differences based on initial career of choice. METHODS: NDP residents' files since the institution of SOAP were reviewed for demographics, initial career choice, financial burden, region of medical school of origin, application and interview history, and pre-screen interview candidate score (high score of 22 - data includes USMLE scores, major clerkship grades, and AOA) used for categorical recruitment. RESULTS: From 2012-16 79 NDP residents have been recruited at UCDenver (82% via SOAP). Median age was 28 years, majority were single (73%), and male (82%). Thirty percent belonged to an under-represented minority group. Mean debt was $156,000 but 20% owe over $250,000. 90% attended US medical schools with 65% from the NRMP "South" region. 86% were recruited as fourth year students. NDPs were categorized as failing to match in general surgery (38%), surgical subspecialties (47%), or other (15%). NDPs applied to median of 68 programs (range 7-200) and granted a median of 8 interviews (range 0-24). NDPs had a mean pre-screening interview score of 13 out of 22 and only 9% would have met the standard threshold to obtain a categorical surgery interview. There were no differences in pre-screening scores in the three groups. 95% NDPs (excluding present year) successfully completed their R1 year (three resigned - one obtained a general surgery spot mid-year and two after matching in non-general surgery fields). 68% NDPs placed in categorical positions after the R1 year. The placement was better for the surgical subspecialty group compared to the other two. CONCLUSIONS: The bias is that due to a more competitive applicant pool recruiting NDPs from surgical subspecialties would be optimal. However, those unmatched surgical subspecialty candidates are no better academically than the unmatched general surgery group, often have career interests that do not always align with scheduled rotations, and may not feel compelled to complete the year if they match. They place minimally better when accounting for those unmatched general surgery NDP R1s continuing as NDP R2s. Ultimately the success in a non-designated preliminary R1 surgery program is alignment of clinical educational opportunities with the needs of the trainee.

Ultrasound-based clinical prediction rule model for detecting papillary thyroid cancer in cervical lymph nodes: A pilot study.

PURPOSE: To identify sonographic features of cervical lymph nodes (LNs) that are associated with papillary thyroid cancer (PTC) and to develop a prediction model for classifying nodes as metastatic or benign. METHODS: This retrospective study included the records of postthyroidectomy patients with PTC who had undergone cervical ultrasound and LN biopsy. LN location, size, shape, hilum, echopattern, Doppler flow, and microcalcifications were assessed. Model selection was used to identify features associated with malignant LNs and to build a predictive, binary-outcome, generalized linear mixed model. A cross-validated receiver operating characteristic analysis was conducted to assess the accuracy of the model for classifying metastatic nodes. RESULTS: We analyzed records from 71 LNs (23 metastatic) in 44 patients (16 with PTC). The predictive model included a nonhomogeneous echopattern (odds ratio [OR], 5.73; 95% confidence interval [CI], 1.07-30.74; p = 0.04), microcalcifications (OR, 4.91; 95% CI, 0.91-26.54; p = 0.06), and volume (OR, 2.57; 95% CI, 0.66-9.99; p = 0.16) as predictors. The model had an area under the curve of 0.74 (95% CI, 0.60-0.85), sensitivity of 65% (95% CI, 50% to 78%), and specificity of 85% (95% CI, 73% to 94%) at the Youden optimal cut point of 0.38. CONCLUSIONS: Nonhomogeneous echopattern, microcalcifications, and node volume were predictive of malignant LNs in patients with PTC. A larger sample is needed to validate this model.

A "safe and effective" protocol for management of post-thyroidectomy hypocalcemia.

BACKGROUND: This study evaluates the outcomes of a protocol to manage hypocalcemia after thyroidectomy (TTX). METHODS: A review of prospectively collected data was performed in 130 patients who underwent TTX after the introduction of a specific protocol. These patients were compared with a control group of 195 patients who underwent TTX the year prior when routine calcium supplementation was utilized and no specific protocol was used. RESULTS: Of the 120 patients in whom the protocol was followed, 44 (37%) patients were classified as high risk, 15 (13%) intermediate risk, and 61 (51%) low risk. The protocol had a sensitivity of 85% and a negative predictive value of 92% for predicting subsequent hypocalcemia. With the implementation of the protocol, there was significant reduction in temporary hypocalcemia events (P = .008) and intravenous calcium drip (P = .49). Also, calcium supplementation was significantly lower in the protocol group (P ≤ .001). CONCLUSIONS: This hypocalcemia protocol identifies patients who do not require additional supplementation and additional monitoring. At the same time, it identifies those who will benefit from supplementation after TTX.

Efficacy of localization studies and intraoperative parathormone monitoring in the surgical management of hyperfunctioning ectopic parathyroid glands.

BACKGROUND: Hyperfunctioning ectopic glands remain an operative challenge in patients with sporadic primary hyperparathyroidism. This study examines the incidence of ectopic glands and the utility of sestamibi scans (MIBI), surgeon-performed ultrasonography, and intraoperative parathormone monitoring in such patients undergoing parathyroidectomy. METHODS: We conducted a retrospective analysis of prospectively collected data from patients who underwent parathyroidectomy from 1980 to 2011 for sporadic primary hyperparathyroidism at a single institution. Demographics, localizing imaging studies, intraoperative parathyroid monitoring dynamics, and surgical outcome for patients with hyperfunctioning ectopic parathyroid glands were studied. RESULTS: Among 1,195 patients who underwent parathyroidectomy for sporadic primary hyperparathyroidism, 120 patients (10%) had hyperfunctioning ectopic glands, which were localized to the neck (n = 66) and mediastinum (n = 54). MIBI had a sensitivity of 85%, specificity of 97%, and positive predictive value (PPV) of 91% for ectopic glands in the neck, whereas in the mediastinum there was a sensitivity of 88%, specificity of 95%, and PPV of 86%. Surgeon-performed ultrasonography had a sensitivity of 81%, specificity of 98%, and PPV of 95% for neck ectopic glands. The overall accuracy of surgeon-performed ultrasonography, MIBI, and intraoperative parathyroid monitoring in the neck or mediastinum was 93%. Overall, operative success was 93% with a multiglandular disease rate of 5%. CONCLUSION: A high operative success rate for hyperfunctioning ectopic glands can be achieved using localization studies and intraoperative parathyroid monitoring. Nevertheless, surgeon judgment remains paramount in the operative direction of this patient population.

Reliability of fine-needle aspiration for thyroid nodules greater than or equal to 4 cm.

BACKGROUND: Fine-needle aspiration (FNA) is considered the diagnostic test of choice in the evaluation of thyroid nodules. Some practice recommendations, however, suggest surgical resection of larger thyroid nodules due to concerns of FNA unreliability in the diagnosis of thyroid malignancy. The purpose of this study was to determine the reliability of FNA in thyroid nodules ≥4 cm. METHODS: Retrospective review of prospectively collected data of 1068 consecutive patients who underwent FNA and thyroidectomy at a single tertiary medical center from 2003 to 2010 was performed. Patients were divided into two groups: those patients with a dominant thyroid nodule ≥4 cm (n = 212) and those patients with a dominant thyroid nodule <4 cm (n = 856). Sensitivity, specificity, and negative and positive predictive values were calculated for FNA results and final histopathology after thyroidectomy. RESULTS: Of 212 patients with lesions ≥4 cm, 35% had thyroid malignancy on final pathology. Conversely, 54% of 856 patients with dominant thyroid nodules <4 cm had a final diagnosis of thyroid cancer after thyroidectomy. FNA demonstrated similar test characteristics among patients with lesions ≥4 cm and <4 cm, with a specificity of 99% (CI: 96%-100%) and 98% (CI: 96%-99.0%), respectively, and a sensitivity of 35% (CI: 23%-49%) and 42% (CI: 37%-46%), respectively. The positive predictive value of FNA was 82% (CI: 75%-100%) for nodules ≥4 cm and 96% (CI: 92%-98%) for nodules <4 cm. Negative predictive value was significantly different, with a value of 82% (CI: 75%-87%) for lesions ≥4 cm and only 59% (CI: 55%-63%) for lesions <4 cm. CONCLUSIONS: The reliability of FNA as a diagnostic test is not affected by the size of thyroid nodules. Routine surgical resection for all thyroid nodules ≥4 cm should not be used as the only independent factor in determining need for surgical resection.

Vitamin D deficiency does not increase the rate of postoperative hypocalcemia after thyroidectomy.

BACKGROUND: Hypocalcemia is a frequent complication of thyroidectomy. Although typically mild and temporary, it can lead to an increased length of stay, readmission, and in some cases be permanent. Controversy exists as to whether vitamin D deficiency (VDD) contributes to post-thyroidectomy hypocalcemia. METHODS: This is a retrospective study of 152 patients who underwent thyroidectomy. Patients with or without VDD were compared. Data were analyzed for demographics, operative procedure, calcium levels, and complications of hypocalcemia. RESULTS: There was no difference in the rates of biochemical or symptomatic hypocalcemia or in the need for readmission between the VDD and non-VDD groups. A multivariate analysis controlling for central neck dissection, parathyroid autotransplant, and preoperative diagnosis confirmed no association between VDD and post-thyroidectomy hypocalcemia. CONCLUSIONS: Despite VDD being common in patients undergoing thyroidectomy, our results do not suggest that this increases the rate of hypocalcemia. Thus, preoperative evaluation/repletion of VDD is unlikely to reduce post-thyroidectomy hypocalcemia rates.

Number of lymph nodes removed during modified radical neck dissection for papillary thyroid cancer does not influence lateral neck recurrence.

BACKGROUND: This study examines the relationship between the number of lymph nodes removed during modified radical neck dissection and the incidence of disease recurrence. METHODS: A retrospective review of 117 patients with papillary thyroid cancer and lateral neck involvement (levels 2-5) who underwent modified radical neck dissection was performed. Data were analyzed for patient demographics, operative procedure, lymph node involvement, complications, radioactive iodine therapy, and disease recurrence. RESULTS: Of 117 patients who underwent modified radical neck dissection, the median follow-up of the entire study group was 25 months (range, 1-256 months). Recurrent disease was found in 8% of patients, with a median time to recurrence of 35 months. The median number of lymph nodes removed during modified radical neck dissection was similar in recurrent and nonrecurrent patients (P = .78). There was also no difference in the median number of positive lymph nodes removed (P = .14) between these 2 groups. On multivariate analysis, however, the number of positive lymph nodes (odds ratio, 1.16 [95% confidence interval, 1.01-1.34]) and tumor size (odds ratio, 1.60 [95% confidence interval, 1.03-2.49]) were independent predictors of recurrence of disease after modified radical neck dissection. CONCLUSION: Recurrence of papillary thyroid cancer after modified radical neck dissection is unrelated to the number of lymph nodes removed. This study suggests that attempts to maximize the number of lymph nodes removed during modified radical neck dissection for papillary thyroid cancer may not be necessary.