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Immune checkpoint inhibitors (ICIs), by reinvigorating CD8+T cell mediated immunity, have revolutionized cancer therapy. Yet, the systemic CD8+T cell distribution, a potential biomarker of ICI response, remains poorly characterized. We assessed safety, imaging dose and timing, pharmacokinetics and immunogenicity of zirconium-89-labeled, CD8-specific, one-armed antibody positron emission tomography tracer 89ZED88082A in patients with solid tumors before and ~30 days after starting ICI therapy (NCT04029181). No tracer-related side effects occurred. Positron emission tomography imaging with 10 mg antibody revealed 89ZED88082A uptake in normal lymphoid tissues, and tumor lesions across the body varying within and between patients two days after tracer injection (n= 38, median patient maximum standard uptake value (SUVmax) 5.2, IQI 4.0–7.4). Higher SUVmaxwas associated with mismatch repair deficiency and longer overall survival. Uptake was higher in lesions with stromal/inflamed than desert immunophenotype. Tissue radioactivity was localized to areas with immunohistochemically confirmed CD8 expression. Re-imaging patients on treatment showed no change in average (geometric mean) tumor tracer uptake compared to baseline, but individual lesions showed diverse changes independent of tumor response. The imaging data suggest enormous heterogeneity in CD8+T cell distribution and pharmacodynamics within and between patients. In conclusion, 89ZED88082A can characterize the complex dynamics of CD8+T cells in the context of ICIs, and may inform immunotherapeutic treatments.

IMPORTANCE: Primary hyperparathyroidism (pHPT) is a common endocrine disorder with many diagnostic and treatment challenges. Despite high-quality guidelines, care is variable, and there is low adherence to evidence-based treatment pathways. OBJECTIVE: To develop quality indicators (QIs) to evaluate the diagnosis and treatment of pHPT that could measure, improve, and optimize quality of care and outcomes for patients with this disease. DESIGN, SETTING, AND PARTICIPANTS: This quality improvement study used a guideline-based approach to develop QIs that were ranked by a Canadian 9-member expert panel of 3 endocrinologists, 3 otolaryngologists, and 3 endocrine surgeons. Data were analyzed between September 2020 and May 2021. MAIN OUTCOMES AND MEASURES: Candidate indicators (CIs) were extracted from published primary hyperparathyroidism guidelines and summarized with supporting evidence. The 9-member expert panel rated each CI on the validity, reliability, and feasibility of measurement. Final QIs were selected from CIs using the modified RAND–University of California, Los Angeles appropriateness methodology. All panelists were then asked to rank the top 5 QIs for primary, endocrine, and surgical care. RESULTS: Forty QIs were identified and evaluated by the expert panel. After 2 rounds of evaluations and discussion, a total of 18 QIs were selected as appropriate measures of high-quality care. The top 5 QIs for primary, endocrine, and surgical care were selected following panelist rankings. CONCLUSIONS AND RELEVANCE: This quality improvement study proposes 18 QIs for the diagnosis and management of pHPT. Furthermore, the top 5 QIs applicable to physicians commonly treating pHPT, including general physicians, internists, endocrinologists, otolaryngologists, and surgeons, are included. These QIs not only assess the quality of care to guide the process of improvement, but also can assess the implementation of evidence-based guideline recommendations. Using these indicators in clinical practice and health system registries can improve quality and cost-effectiveness of care for patients with pHPT.

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Supplemental digital content is available in the text.

Secondary protein‐losing enteropathy (PLE) is a rare complication following pediatric liver transplantation (LT), mostly related to venous outflow obstruction of the liver. Here, we discuss a thus far unknown cause of secondary PLEfollowing pediatric LT. A 7‐month‐old boy underwent LTwith biliary anastomosis using a Roux‐en‐Y jejunal loop. Eleven months later he developed PLE. Routine diagnostic workup was negative. No hepatic outflow obstruction was detected during catheterization. Although the hepatic venous pressure gradient was slightly increased (10 mm Hg), there were no clinical signs of portal hypertension. Albumin scintigraphy with specific early recordings suggested focal albumin intestinal entry in the jejunal Roux‐en‐Y loop. Local bacterial overgrowth or local lymphangiectasia, possibly due to (venous) congestion, was considered. Treatment with metronidazole did not improve albumin loss. Next, surgical revision of the jejunal Roux‐en‐Y loop was performed. The explanted loop contained a small abnormal area with a thin hyperemic mucosa, near the former anastomosis. Histopathological analysis showed changes both in the blood vessels and the lymphatic vessels with focal deeper chronic active inflammation resulting in congestion of vessels, hampering lymphatic outflow leading to lymphangiectasia and patchy distortion of lymphatic vessels. Following surgical revision, secondary PLEdisappeared, up to now, 1.5 year post revision. The authors detect focal protein loss and treat protein‐losing enteropathy in a pediatric transplant recipient via surgical revision of the Roux‐en‐Y loop.

Secondary protein-losing enteropathy (PLE) is a rare complication following pediatric liver transplantation (LT), mostly related to venous outflow obstruction of the liver. Here, we discuss a thus far unknown cause of secondary PLE following pediatric LT. A 7-month-old boy underwent LT with biliary anastomosis using a Roux-en-Y jejunal loop. Eleven months later he developed PLE. Routine diagnostic workup was negative. No hepatic outflow obstruction was detected during catheterization. Although the hepatic venous pressure gradient was slightly increased (10 mm Hg), there were no clinical signs of portal hypertension. Albumin scintigraphy with specific early recordings suggested focal albumin intestinal entry in the jejunal Roux-en-Y loop. Local bacterial overgrowth or local lymphangiectasia, possibly due to (venous) congestion, was considered. Treatment with metronidazole did not improve albumin loss. Next, surgical revision of the jejunal Roux-en-Y loop was performed. The explanted loop contained a small abnormal area with a thin hyperemic mucosa, near the former anastomosis. Histopathological analysis showed changes both in the blood vessels and the lymphatic vessels with focal deeper chronic active inflammation resulting in congestion of vessels, hampering lymphatic outflow leading to lymphangiectasia and patchy distortion of lymphatic vessels. Following surgical revision, secondary PLE disappeared, up to now, 1.5 year post revision.

Programmed cell death protein-1/ligand-1 (PD-1/PD-L1) blockade is effective in a subset of patients with several tumor types, but predicting patient benefit using approved diagnostics is inexact, as some patients with PD-L1-negative tumors also show clinical benefit1,2. Moreover, all biopsy-based tests are subject to the errors and limitations of invasive tissue collection3–11. Preclinical studies of positron-emission tomography (PET) imaging with antibodies to PD-L1 suggested that this imaging method might be an approach to selecting patients12,13. Such a technique, however, requires substantial clinical development and validation. Here we present the initial results from a first-in-human study to assess the feasibility of imaging with zirconium-89-labeled atezolizumab (anti-PD-L1), including biodistribution, and secondly test its potential to predict response to PD-L1 blockade (ClinicalTrials.gov identifiers NCT02453984 and NCT02478099). We imaged 22 patients across three tumor types before the start of atezolizumab therapy. The PET signal, a function of tracer exposure and target expression, was high in lymphoid tissues and at sites of inflammation. In tumors, uptake was generally high but heterogeneous, varying within and among lesions, patients, and tumor types. Intriguingly, clinical responses in our patients were better correlated with pretreatment PET signal than with immunohistochemistry- or RNA-sequencing-based predictive biomarkers, encouraging further development of molecular PET imaging for assessment of PD-L1 status and clinical response prediction.

Little is known about long-term quality of life (QoL) of survivors of pediatric differentiated thyroid carcinoma. Therefore, this study aimed to evaluate generic health-related QoL (HRQoL), fatigue, anxiety, and depression in these survivors compared with matched controls, and to evaluate thyroid cancer-specific HRQoL in survivors only.

This review describes the main benefits of using long axial field of view (LAFOV) PET in clinical applications. As LAFOV PET is the latest development in PET instrumentation, many studies are ongoing that explore the potentials of these systems, which are characterized by ultra-high sensitivity. This review not only provides an overview of the published clinical applications using LAFOV PET so far, but also provides insight in clinical applications that are currently under investigation. Apart from the straightforward reduction in acquisition times or administered amount of radiotracer, LAFOV PET also allows for other clinical applications that to date were mostly limited to research, e.g., dual tracer imaging, whole body dynamic PET imaging, omission of CT in serial PET acquisition for repeat imaging, and studying molecular interactions between organ systems. It is expected that this generation of PET systems will significantly advance the field of nuclear medicine and molecular imaging.

Introduction:Treatment for differentiated thyroid carcinoma (DTC) in pediatric patients is based mainly on evidence from adult series due to lack of data from pediatric cohorts. Our objective was to evaluate presentation, treatment-related complications, and long-term outcome in patients with pediatric DTC in The Netherlands.Patients and Methods:In this nationwide study, presentation, complications, and outcome of patients with pediatric DTC (age at diagnosis ≤18 y) treated in The Netherlands between 1970 and 2013 were assessed using medical records.Results:We identified 170 patients. Overall survival was 99.4% after a median follow-up of 13.5 years (range 0.3–44.7 y). Extensive follow-up data were available for 105 patients (83.8% women), treated in 39 hospitals. Median age at diagnosis was 15.6 years (range 5.8–18.9 y). At initial diagnosis, 43.8% of the patients had cervical lymph node metastases; 13.3% had distant metastases. All patients underwent total thyroidectomy. Radioiodine was administered to 97.1%, with a median cumulative activity of 5.66 GBq (range 0.74–35.15 GBq). Life-long postoperative complications (permanent hypoparathyroidism and/or recurrent laryngeal nerve injury) were present in 32.4% of the patients. At last known follow-up, 8.6% of the patients had persistent disease and 7.6% experienced a recurrence. TSH suppression was not associated with recurrences (odds ratio 2.00, 95% confidence interval 0.78–5.17, P= .152).Conclusions:Survival of pediatric DTC is excellent. Therefore, minimizing treatment-related morbidity takes major priority. Our study shows a frequent occurrence of life-long postoperative complications. Adverse effects may be reduced by the centralization of care, which is crucial for children with DTC.

Background:Patients with differentiated thyroid carcinoma (DTC) have a favorable prognosis after treatment with thyroidectomy, radioiodine, and TSH suppression. However, treatment is associated with long-term cardiovascular toxicity. The aim of this study was to evaluate whether there is an increased risk of atrial fibrillation (AF) in DTC patients and whether AF occurrence is related to DTC treatment.Patients and Methods:Incident AF was compared between 518 DTC patients and 1563 matched controls. A cumulative incidence curve was plotted, and competing risk regression analyses with adjustment for all-cause mortality were performed. Within the DTC cohort, associations between time-varying DTC treatment variables and incident AF were analyzed.Results:For both cohorts, the mean age was 48.6 years (75% of subjects were women). The AF incidence rate was 6.2/1000 person-years for DTC patients and 2.7/1000 person-years for controls. DTC patients had a 2.25-fold (95% confidence interval [CI], 1.40–3.63) and 2.47-fold (95% CI, 1.55–3.95) increased AF risk in crude and fully adjusted analyses, respectively. Within the DTC cohort, the TSH level (which was suppressed in 85.7% of patients) was not associated with AF, whereas a higher cumulative radioiodine dose slightly increased AF risk: subdistribution hazard ratio, 1.04 (95% CI, 1.01–1.08) per 50 mCi (1.85 GBq) increase, after adjustment.Conclusion:Patients with DTC have an increased AF risk, independent from established AF risk factors. We could not demonstrate a relation between TSH and AF, whereas a higher cumulative radioiodine dose was associated with a slightly increased AF risk. Electrocardiogram screening for AF may be warranted during follow-up of DTC patients to allow early diagnosis and treatment of AF and to prevent its complications.

Objective:The primary objective was to evaluate the short- and long-term toxic effects of radioiodine (131I) therapy on bone marrow function in differentiated thyroid carcinoma (DTC) patients. The secondary objective was to define characteristics of patients at risk for impaired bone marrow function after 131I treatment.Patients and Methods:DTC patients treated with 131I between 1989 and 2013 were included. We excluded patients with morbidities or treatments that could have influenced blood count parameters. Baseline platelets, leukocytes, and hemoglobin levels were compared with blood counts at 3 and 6 months and at 1 and 5 years after treatment. Logistic multivariate regression analyses were performed to determine patient characteristics associated with thrombocytopenia.Results:We included 331 patients. Mean ± SD age was 47.5 ± 17.2 years, and 74.0% were female. Posttreatment platelets were significantly decreased at 6 months and 1 year, as compared with baseline. Leukocyte counts were also decreased at 3 and 6 months and at 1 year after treatment. No decreases in hemoglobin were found. Five years after treatment, platelet and leukocyte counts were comparable with baseline. Fourteen patients (4.2%) developed transient posttreatment thrombocytopenia. Risk factors for thrombocytopenia were older age, T4 tumor stage, male gender, and cumulative dose 131I. After a multivariate regression analysis, the cumulative dose 131I remained independently associated with thrombocytopenia.Conclusion:Posttreatment platelets and leukocytes were transiently decreased compared with pretreatment values in a general DTC population. Cumulative 131I dose was independently associated with thrombocytopenia. Platelets and leukocytes normalized to baseline levels 5 years after treatment, implying that in most patients the clinical effects of bone marrow toxicity are limited.

Human epidermal growth factor receptor-2 (HER2) directed therapy potentially can be improved by insight in drug effects on HER2 expression. This study evaluates the effects of the EGFR/HER2 tyrosine kinase inhibitor lapatinib, the heat shock protein-90 inhibitor 17AAG, and their combination, on HER2 expression with in vivoHER2-PET imaging. Lapatinib and 17AAG effects on EGFR and HER2 membrane expression were determined in vitrousing flow cytometry of human SKBR3 tumor cells. Effect of lapatinib on HER2 internalization was studied in vitroby 89Zr-trastuzumab-F(ab′)2internalization. For in vivoevaluation, 89Zr-trastuzumab-F(ab′)2μPET imaging was performed two times with a 7 day interval. Lapatinib was administered for 6 days, starting 1 day after the baseline scan. 17AAG was given 1 day before the second 89Zr-trastuzumab-F(ab′)2injection. Imaging data were compared with ex vivobiodistribution analysis and HER2 immunohistochemical staining. 17AAG treatment lowered EGFR expression by 41% (P= 0.016) and HER2 by 76% (P= 0.022). EGFR/HER2 downregulation by 17AAG was inhibited by lapatinib pretreatment. Lapatinib reduced internalization of 89Zr-trastuzumab-F(ab′)2with 25% (P= 0.0022). 89Zr-trastuzumab-F(ab′)2tumor to blood ratio was lowered 32% by lapatinib (P= 0.00004), 34% by 17AAG (P= 0.0022) and even 53% by the combination (P= 0.011). Lapatinib inhibits HER2 internalization and 17AAG lowers HER2 membrane expression. Both drugs reduce 89Zr-trastuzumab-F(ab′)2tumor uptake. Based on our findings, supported by previous preclinical data indicating the antitumor potency of lapatinib in combination with HSP90 inhibition, combination of these drugs deserves further investigation.