Tumor Growth Rate to Predict the Outcome of Patients with Neuroendocrine Tumors: Performance and Sources of Variability.

INTRODUCTION: Tumor growth rate (TGR), percentage of change in tumor volume/month, has been previously identified as an early radiological biomarker for treatment monitoring in neuroendocrine tumor (NET) patients. We assessed the performance and reproducibility of TGR at 3 months (TGR3m) as a predictor factor of progression-free survival (PFS), including the impact of imaging method and reader variability. METHODS: Baseline and 3-month (±1 month) CT/MRI images from patients with advanced, grade 1-2 NETs were retrospectively reviewed by 2 readers. Influence of number of targets, tumor burden, and location of lesion on the performance of TGR3m to predict PFS was assessed by uni/multivariable Cox regression analysis. Agreement between readers was assessed by Lin's concordance coefficient (LCC) and kappa coefficient (KC). RESULTS: A total of 790 lesions were measured in 222 patients. Median PFS was 22.9 months. On univariable analysis, number of lesions (

Self-Administration of Long-Acting Somatostatin Analogues in NET Patients-Does It Affect the Clinical Outcome?

Background and Objectives: Long-acting somatostatin analogues (SSA) (octreotide LAR and lanreotide Autogel) are recommended as first line treatment of locally advanced or metastatic well-differentiated neuroendocrine tumors (NETs) with a good expression of somatostatin receptor (SSTR). Both of these SSAs are usually administered via injections repeated every 4 weeks. The purpose of the study was to compare the route of SSA administration (injection performed by professional medical staff and self-administration of the drug) with progression-free survival. Materials and methods: 88 patients in 2019 and 96 patients in 2020 with locally advanced or metastatic well-differentiated NETs were included in the study. All patients had a good expression of SSTR type 2 and had been treated for at least 3 months with a stable dose of long-acting somatostatin analogue every 4 weeks. All of them had received training on drug self-injections from professional NET nurses at the beginning of the COVID-19 epidemic. Results: The rate of NET progression in the study group in 2020 was higher than in 2019 29.1% vs. 18.1% (28 vs. 16 cases), p = 0.081. Conclusions: The method of administration of long-acting SSA injection performed by professional medical staff vs. self-injection of the drug may significantly affect the risk of NET progression. The unequivocal confirmation of such a relationship requires further observation.

Value of Tumor Growth Rate (TGR) as an Early Biomarker Predictor of Patients' Outcome in Neuroendocrine Tumors (NET)-The GREPONET Study.

INTRODUCTION: Tumor growth rate (TGR; percent size change per month [%/m]) is postulated to be an early radiological biomarker to overcome limitations of RECIST. This study aimed to assess the impact of TGR in neuroendocrine tumors (NETs) and potential clinical and therapeutic applications. MATERIALS AND METHODS: Patients (pts) with advanced grade (G) 1/2 NETs from the pancreas or small bowel initiating systemic treatment (ST) or watch and wait (WW) were eligible. Baseline and follow-up scans were retrospectively reviewed to calculate TGR at pretreatment (TGR0), first follow-up (TGRfirst), and 3(±1) months of study entry (TGR3m). RESULTS: Out of 905 pts screened, 222 were eligible. Best TGRfirst (222 pts) cutoff was 0.8 (area under the curve, 0.74). When applied to TGR3m (103 pts), pts with TGR3m <0.8 (66.9%) versus TGR3m ≥ 0.8 (33.1%) had longer median progression-free survival (PFS; 26.3 m; 95% confidence interval [CI] 19.5-32.4 vs. 9.3 m; 95% CI, 6.1-22.9) and lower progression rate at 12 months (7.3% vs. 56.8%; p = .001). WW (vs. ST) and TGR3m ≥ 0.8 (hazard ratio [HR], 3.75; 95% CI, 2.21-6.34; p < .001) were retained as factors associated with a shorter PFS in multivariable Cox regression. TGR3m (HR, 3.62; 95% CI, 1.97-6.64; p < .001) was also an independent factor related to shorter PFS when analysis was limited to pts with stable disease (81 pts). Out of the 60 pts with TGR0 data available, 60% of pts had TGR0 < 4%/month. TGR0 ≥ 4 %/month (HR, 2.22; 95% CI, 1.15-4.31; p = .018) was also an independent factor related to shorter PFS. CONCLUSION: TGR is an early radiological biomarker able to predict PFS and to identify patients with advanced NETs who may require closer radiological follow-up. IMPLICATIONS FOR PRACTICE: Tumor growth rate at 3 months (TGR3m) is an early radiological biomarker able to predict progression-free survival and to identify patients with advanced neuroendocrine tumors who may require closer radiological follow-up. It is feasible to calculate TGR3m in clinical practice and it could be a useful tool for guiding patient management. This biomarker could also be implemented in future clinical trials to assess response to therapy.

Radiolabeled peptides: current and new perspectives.

Radiolabeled peptides have been the subject of research for over 20 years and during that time possibility/variety of peptide receptor imaging and later targeted radiotherapy increased significantly. The targeted receptors belong to the large family of G-protein-coupled receptors or tyrosine kinases receptors partially connected with them. They both regulate large signaling networks, control multiple cell functions and are implicated in many diseases including cancers. The essential feature of peptides used in nuclear medicine involves their ability to binding with high affinity and specify to their receptors overexpressed on tumor cells. Currently most important peptide radiotracers are somatostatin, GLP-1, bombesin, gastrin/cholecystokinin-2, neurokinin type 1, CXCR4, EGF, VEGF and integrins. These tracers are mainly based on nuclides which are radiometals or on 18F and may be used in both SPECT or PET techniques as well as for hybrid imaging. Using of chelators suitable for peptide labeling with diagnostic and therapeutic radionuclids enables the theranostic approach. In this review we will provide a brief overview over currently available radiopharmaceuticals based on different groups of peptides.

Increased incidence of myxedema coma during the COVID-19 pandemic and in the post pandemic era: a single-center case series.

The COVID-19 pandemic was a major challenge for all health care employees, but it was also difficult for patients to gain access to health care services. Myxedema coma (MC) is an extremely rare but potentially fatal endocrine emergency. The aim of the study was to report an increased incidence of life-threatening myxedema coma that occurred in relation to the COVID-19 pandemic. In this paper, we report a cohort of 11 patients with MC who were treated at the University Hospital in Krakow, Poland, in the period from 2015 to 2023. Only 1 case of MC was recorded in the period from 2015 to 2019, and, in the same area, 10 cases of MC were recorded after the start of COVID-19 pandemic until present. Hypothyroidism was diagnosed de novo in 2 (18%) patients; the remaining patients were severely hypothyroid due to therapy non-compliance. Nine patients had primary hypothyroidism, and 2 had central hypothyroidism. Besides longstanding hypothyroidism, an additional precipitating factor for MC was identified in 4 (36%) of the patients. Due to the inaccessibility of parenteral levothyroxine, patients were treated with oral, mostly liquid, form of levothyroxine. The mortality rate in this cohort was 27.2%. In conclusion, the increase of the incidence of MC, which is a life-threatening complication of inadequately treated hypothyroidism, during the COVID-19 pandemic, when resources were limited, and in the post-pandemic era, underlines the importance of adequate communication with patients and of long-term availability of primary care for patients with thyroid disease.

24-hour urine metanephrine excretion in patients diagnosed with adrenal incidentaloma: impact of commonly used drugs on a clinical decision.

INTRODUCTION: Incidentaloma is an adrenal tumor detected during diagnostic imaging performed for extra­adrenal causes. Evaluation of metanephrine concentrations in a 24­hour urine collection can be a significant challenge in patients with multiple medications and comorbidities. OBJECTIVES: The aim of this study was to evaluate the effect of commonly used groups of drugs on metanephrine levels in the 24­hour urine collection. PATIENTS AND METHODS: A total of 1051 patients with adrenal mass below 10 Hounsfield units on unenhanced computed tomography were included in the study. Patients diagnosed with Cushing or Conn syndrome, adrenal carcinoma, pheochromocytoma, active extra­adrenal malignant neoplasms, and exacerbation of severe illnesses were excluded. Metanephrine, normetanephrine, and 3­methoxytyramine in the 24­hour urine collection were measured by high­performance liquid chromatography with electrochemical detection. Information on concomitant medication (ß­blockers, calcium channel blockers [CCBs], loop diuretics, thiazide diuretics, potassium­sparing diuretics, α­blockers, angiotensin­converting enzyme inhibitors / angiotensin II receptor blockers, metformin, nonmetformin antidiabetic drugs [NMADs], lipid­lowering drugs, proton pump inhibitors, levothyroxine, thyreostatics, antidepressants, neuroleptics, benzodiazepines, glucocorticosteroids, inhaled B­receptor agonists, and ipratropium) was collected from each patient. RESULTS: The urinary excretion of normetanephrine was significantly higher in the patients on ß­blockers, CCBs, loop diuretics, α­blockers, NMADs, and neuroleptics. α­Blockers increased urine metanephrine concentration, and NMADs, antidepressants, and glucocorticosteroids lowered it. There was no association between the analyzed drugs and urinary 3­methoxytyramine level. CONCLUSIONS: Many drug groups interfere with the measurement of urinary fractionated metanephrines. These interactions should be taken into account during interpretation of a hormonal evaluation, as they can be crucial for further management, especially for making a decision on surgical treatment.

Prediction of disease recurrence in patients after complete pancreatic NET (PanNET) G2 resection.

INTRODUCTION: The number of detected pancreatic neuroendocrine tumours (PanNETs) has been increasing over the last decades. Surgical resection remains the only potentially curative treatment, but the management is still controversial. This study aimed to compare patients after radical PanNET G2 resection to determine the most important predictive factors for relapse. MATERIAL AND METHODS: All patients with histologically confirmed PanNET G2 who underwent successful surgery between 2006 and 2020 with the intention of radical treatment were enrolled. RESULTS: In total, 44 patients were eligible for the analysis. The average follow-up was 8.39 ± 4.5 years. Disease recurrence was observed in 16 (36.36%) patients. The dominant location of the primary tumour was the tail of the pancreas (43.18%), especially in the subgroup with disease recurrence (56.25%). The smallest tumour diameter associated with the PanNET G2 recurrence was 22 mm. The relationship between the largest dimension of the tumour with a division of < 4 cm vs. > 4 cm and the relapse was close to statistical significance. Recurrence was associated with a larger tumour size (p = 0.018). There was a statistically significant relationship and a weak correlation between Ki-67 (p = 0.036, V Cramer = 0.371) and disease relapse. CONCLUSION: For the group of PanNET G2 patients after radical surgery, the overall risk of recurrence was 36.36%, with the highest rate in the first 5 years after surgery, but in individual cases it occurred significantly later, even 10 years after surgery. The most important predictive factors of the PanNET G2 recurrence was Ki-67 over 5.75% and size of tumour > 4 cm.

Differences in clinical characteristics, treatment, and outcomes of sporadic and MEN-1-related insulinomas.

INTRODUCTION: Although in most cases insulinomas are small, benign, sporadic tumours, they can also be associated with hereditary syndromes, most commonly multiple endocrine neoplasia type 1 (MEN-1). Such a diagnosis significantly affects patient management. The objective was to elucidate the clinical differences between sporadic and MEN-1-linked insulinoma. MATERIAL AND METHODS: Comparison of clinical and histopathological characteristics, types of surgery, and outcomes of patients with sporadic and MEN-1-related insulinoma diagnosed between 2015 and 2022. RESULTS: There were 17 cases of insulinomas that underwent MEN-1 genetic testing (10 women and 7 men). In 7 cases, the mutation in the menin gene was confirmed. The median age at the time of diagnosis of sporadic insulinoma related to MEN-1 was 69 years (range 29-87) and 31.5 years (16-47), respectively. Primary hyperparathyroidism (PHP) was found in 6 of 7 patients with MEN-1-related insulinoma, while in none of the patients without MEN-1 mutations. Multifocal pancreatic NETs were found in 3 patients with MEN-1 syndrome, while in all sporadic cases there was a single pancreatic tumour. Two patients with insulinoma related to MEN-1 had a positive familial history of MEN-1-related diseases, while none with sporadic form. Dissemination at diagnosis was found in 4 cases, including 3 patients with insulinoma related to MEN-1-related insulinoma. Patients with sporadic and MEN-1-related insulinoma did not differ in tumour size, Ki-67 proliferation index, and outcome. CONCLUSIONS: Of all the features evaluated, only the multifocal nature of pancreatic neuroendocrine tumour (PanNET) lesions and a positive family history differentiated between patients with sporadic and MEN-1-related insulinomas. An age of insulinoma diagnosis of less than 30 years may be a strong indicator of an increased risk of MEN-1 syndrome.

18F-fluorodeoxyglucose and 18F-sodium fluoride positron emission tomography imaging in assessing early stages of aortic valve degeneration after transcatheter aortic valve implantation.

INTRODUCTION: Transcatheter aortic valve implantation (TAVI) is a standard treatment for severe aortic stenosis, primarily in elderly patients. With an increasing number of procedures and younger patients, understanding the valve degeneration and its risk factors becomes crucial. OBJECTIVES: We aimed to utilize 18F­sodium fluoride (18F­NaF) and 18F­fluorodeoxyglucose (18F­FDG) positron emission tomography/computed tomography (PET/CT) to evaluate early TAVI valve degeneration. PATIENTS AND METHODS: In this prospective study with a prespecified follow­up protocol, 71 TAVI patients underwent baseline transthoracic and transesophageal echocardiography, and PET/CT with 18F­NaF and 18F­FDG. Of these, 31 patients completed 24­month control examinations, while the others were lost to mortality and the COVID­19 pandemic. We measured PET tracer activity and compared 18F­NaF and 18F­FDG PET/CT uptake at baseline and 24­month follow­up. RESULTS: PET/CT and echocardiography data were analyzed for 31 of the 71 enrolled TAVI patients at a median age of 84 years (interquartile range, 80-86). After TAVI, an improvement in the valve function was observed. During follow­up, the valve function remained stable. PET/CT demonstrated an increase in 18F­FDG maximal uptake in the inner (tissue­to­background ratio, P = 0.009) and outer (P = 0.01) sides of the TAVI valve stent, but no difference in 18F­NaF maximal activity (inner, P = 0.17; outer, P = 0.57). CONCLUSIONS: Twenty­four months post­TAVI, an increase in 18F­FDG uptake, indicative of inflammation, was observed in the valve, while the uptake of the calcification marker (18F­NaF) remained stable. Theseobservations might suggest early stages of TAVI valve degeneration, although further investigation is required to confirm this interpretation.

Imaging of inflamed carotid artery atherosclerotic plaques with the use of 99mTc-HYNIC-IL-2 scintigraphy in end-stage renal disease patients.

PURPOSE: Identification of vulnerable plaques remains crucial for better cardiovascular risk assessment. At least 20% of inflammatory cells within unstable (vulnerable) plaques comprise T lymphocytes, which contain receptors for interleukin-2 (IL-2); those receptors can be identified by scintigraphy with radiolabelled IL-2.The aim of this study was to identify the "inflamed" (vulnerable) plaques by scintigraphy using IL-2 labelled with (99m)Tc in the selected, high cardiovascular risk group of end-stage renal disease (ESRD) patients. METHODS: A total of 28 patients (18 men, 10 women, aged 55.2 ± 9.6 years, 17 on peritoneal dialysis, 11 on haemodialysis) underwent common carotid artery (CCA) scintigraphy with the use of (99m)Tc-hydrazinonicotinamide (HYNIC)-IL-2. In all cases, ultrasound examination of the CCA was performed and levels of selected proinflammatory factors, atherogenic markers and calcium-phosphate balance parameters were measured. Finally, the target to non-target (T/nT) ratio of IL-2 uptake in atherosclerotic plaques with intima-media thickness (IMT), classic cardiovascular risk factors and concentrations of the measured factors were compared. RESULTS: Increased (99m)Tc-HYNIC-IL-2 uptake in atherosclerotic plaques in 38/41 (91%) cases was detected. The median T/nT ratio of focal (99m)Tc-HYNIC-IL-2 uptake in atherosclerotic plaques was 2.35 (range 1.23-3.63). The mean IMT value on the side of plaques assessed by scintigraphy was 0.79 ± 0.18 mm (median 0.8, range 0.5-1.275). Correlations between T/nT ratio and homocysteine (R = 0.22, p = 0.037), apolipoprotein B (apoB) (R = 0.31, p = 0.008), apoB to apoA-I ratio (R = 0.29, p = 0.012) and triglyceride concentration (R = 0.26, p = 0.021) were detected. A lower T/nT ratio in patients with better parameters of nutritional status (haemoglobin, albumin, adiponectin) in comparison with patients with worse nutritional parameters (3.20 ± 0.5 vs 2.16 ± 0.68, p = 0.025) was revealed as well as a difference between values of T/nT ratio in groups of patients with values of apoB, soluble CD40 ligand and asymmetric dimethylarginine above and below median (3.18 ± 0.52 vs 2.16 ± 0.68, p = 0.031). No statistically significant association was found between T/nT ratio and mean value of either IMT or classic cardiovascular risk factors. CONCLUSION: Scintigraphy with the use of (99m)Tc-HYNIC-IL-2 can be a tool for inflamed atherosclerotic (vulnerable) plaque visualization within CCA in ESRD patients. Quantitative results of carotid artery scintigraphy with (99m)Tc-HYNIC-IL-2 correlate with serum concentration of selected cardiovascular risk markers.

Additional Value of [18F]FDG PET/CT in Detection of Suspected Malignancy in Patients with Paraneoplastic Neurological Syndromes Having Negative Results of Conventional Radiological Imaging.

BACKGROUND: Paraneoplastic neurological syndromes (PNS) affecting the CNS (central nervous system) are rare, presenting in less than 1% of all those with cancer. The pathogenesis of paraneoplastic neurological syndromes is not fully understood, but it is presumed to result from an immune attack on the underlying malignancy. The presence of different types of onconeural antibodies may occur in different tumors and can lead to different clinical manifestations, making the early detection of cancers challenging. AIM: An evaluation of [18F]FDG PET/CT in neoplastic tumor detection in patients with paraneoplastic neurological syndromes having negative or unremarkable results of conventional radiological imaging. METHODS: Among all patients diagnosed with paraneoplastic neurological syndromes in the Neurology Department in 2016-2020, 15 patients with unremarkable conventional radiological findings who underwent [18F]FDG PET/CT were included in the study. RESULTS: [18F]FDG PET/CT enabled localization of suspected malignancy in 53% (8 of 15) of PNS cases with previous unremarkable conventional radiological findings. CONCLUSION: [18F]FDG PET/CT may be considered as a useful tool for neoplastic tumor detection in patients with paraneoplastic neurological syndromes, accelerating the diagnostic process and enabling faster initiation of appropriate treatment.

Pituitary stalk metastasis of a neuroendocrine tumour of unknown origin.

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Prevalence of Selected Single-Nucleotide Variants in Patients with Neuroendocrine Tumors-Potential Clinical Relevance.

INTRODUCTION: The genetic basis of neuroendocrine tumors (NETs), whose incidence is continuously increasing, is still not fully defined. The majority of NETs are sporadic, and only a small percentage occur as part of hereditary genetic syndromes. However, the associations of multiple genetic variants have been found as clinically relevant in several neoplasms. The aim of this study was to evaluate whether selected, literature-based genetic variants may have a potential role in NET susceptibility and clinical outcome in Polish patients. MATERIALS/METHODS: A total of 185 patients recruited from one clinical center were enrolled. In the first part of the study, the molecular analysis including four single-nucleotide variants (rs8005354 (DAD1, NM_001344 intronic T/C substitution), rs2069762 (T/G substitution in the promoter region of the IL2 NM_000586), rs3731198 (CDKN2A, NM_000077 intronic A/G substitution), and rs1800872 (C/A substitution in the promoter region of the IL10 NM_000572)) was performed in 107 participants (49 patients with NETs with different primary site NETs and a control group of 58 healthy adult volunteers). In the second stage, the same single-nucleotide polymorphisms (SNPs) were assessed in 127 patients with NET and analyzed in terms of clinical data (primary site, serum CgA concentration, and metastatic disease). RESULTS: The analysis of homozygotes revealed a statistically significant higher prevalence of TT homozygotes of variant rs3731198 in the control group (p = 0.0209). In NET patients, there was a statistically significant higher prevalence of GG homozygotes of variant rs1800872 (p = 0.003). There was a statistically significant correlation between the rs3731198 variant and lymph node metastases (p = 0.0038 with Bonferroni correction). CONCLUSIONS: Our study indicates that GG homozygotes of variant rs1800872 are more often observed in NET patients, while TT homozygotes of variant rs3731198 are less frequent in this group. The rs3731198 variant may be related to an increased risk of lymph node metastasis. Further, larger multicenter studies are warranted to evaluate the potential genetic factors of sporadic NETs.

Adrenal bleeding due to pheochromocytoma - A call for algorithm.

Background: Adrenal hemorrhage is a rare, usually life-threating complication. The most common neoplasm resulting in spontaneous adrenal bleeding is pheochromocytoma and it accounts for nearly 50% of cases. Currently, the recommendations for the diagnosis and management of patients with adrenal bleeding due to pheochromocytoma are unavailable. Materials and methods: We performed a database search for all pheochromocytoma patients, diagnosed and treated from 2005 to 2021 in tertiary endocrinology center. 206 patients were identified, 183 with complete data were included in the analysis. We investigated clinicopathological characteristics, treatment and outcomes of hemorrhagic pheochromocytoma cases and characterize our approach to perioperative diagnosis and medical management. Finally our experiences and data from previously published articles concerning adrenal hemorrhage were analyzed to propose a diagnostic and therapeutic algorithm for hemorrhagic pheochromocytomas. Results: In the whole group, seven patients (4 men and 3 women) with adrenal bleeding were found, (3.8%). Median patient's age was 49 years (range: 36-78 years). The most common manifestation of adrenal bleeding was acute abdominal pain (5/7). Two patients developed shock. Hormonal assessment was performed in five patients, based on 24-hour urinary fractionated metanephrines with urinary 3-methoxytyramine. Normetanephrine was elevated in all patients, metanephrine and 3-methoxytyramine - in four cases (4/5). Most patients (6/7) had symptoms suggesting pheochromocytoma before hemorrhage - most commonly paroxysmal hypertension (4/7). One patient died, before the diagnosis of adrenal bleeding was made. Diagnostic imaging performed in six out of seven patients revealed adrenal tumor, with median largest diameter equal to 7.4 cm (range: 5-11 cm). Five patients had elective surgery, in one case an urgent surgery was performed. In all cases the diagnosis of pheochromocytoma was confirmed in postoperative histopathology or in autopsy. The perioperative survival rate was 85.7%. Conclusions: Diagnosis of pheochromocytoma should be always considered in patients with adrenal bleeding, especially with accompanying abdominal pain, hemodynamic shock and previous history of pheochromocytoma-associated symptoms. Lack of proper diagnosis of pheochromocytoma before surgery is associated with an additional perioperative risk. To improve the decision making in this life-threatening clinical situation, based on our results and literature data, we proposed a diagnostic and treatment algorithm.

Potential value of pre- and post-therapy [68Ga]Ga-DOTA-TATE PET/CT in the prognosis of response to PRRT in disseminated neuroendocrine tumors.

Background: Peptide receptor radionuclide therapy (PRRT) is one of the most effective therapeutic options for the treatment of metastatic, well-differentiated neuroendocrine tumors (NETs). It improves progressive disease-free survival and enables the control of hormone secretion in functioning tumors.Currently, there are no clearly established predictors of response to PRRT. The main factors hindering such a prediction are the heterogeneity of somatostatin receptor expression within and between lesions, lack of standardized parameters for functional imaging, and the use of different PRRT protocols.The main goal of our study was to quantify SUVmax changes in [68Ga]Ga-DOTA-TATE PET/CT scans as a potential predictor of long-term response to PRRT. Material and methods: Out of 20 patients treated with PRRT using [177Lu]Lu and/or [177Lu]Lu/[90Y]Y-DOTA-TATE in 2017-2019 due to dissemination of neuroendocrine neoplasm, 12 patients underwent [68Ga]Ga-DOTA-TATE PET/CT on average 3.1 months before and 4.5 months after PRRT and were eligible for the analysis.In total, 76 NET lesions were evaluated. We measured SUVmax for every lesion in both PET/CT scans (before and after PRRT). Those values were corrected by liver SUVmax and liver SUVmean measured in volumetric analysis and specified as SUVlmax and SUVlmean. As a next step, changes in SUVlmax and SUVlmean were assessed based on both PET/CT scans. Finally, results were correlated with the clinical outcome assessed as progressive disease, disease stabilization, or partial response. Results: The mean follow-up period was 19.9 months. Progressive disease, partial response, and disease stabilization were found in five, two, and five patients, respectively. Among patients with a partial response, the decrease in mean SUVlmax was 66.3% when compared to baseline. In patients with stable disease, the decrease in SUVlmax was 30.3% when compared to baseline. In patients with progressive disease, the mean increase in SUVlmax was 9.1% when compared to baseline. The changes in SUVlmean were -69,8%, -30.8%, and -3.7%, respectively. Conclusions: A decrease in the SUVmax value in NET lesions, corrected by normal liver tissue uptake assessed in [68Ga]Ga-DOTA-TATE PET/CT scans, indicates a lower risk for NET progressive disease within 20 months after PRRT and may constitute an additional and independent parameter for the estimation of overall risk for disease progression.

Value of Peptide Receptor Radionuclide Therapy as Neoadjuvant Treatment in the Management of Primary Inoperable Neuroendocrine Tumors.

INTRODUCTION: Neuroendocrine neoplasms including neuroendocrine tumors (NETs) are often diagnosed as primary disseminated or inoperable. In those cases, systemic extensive therapy is necessary, but radical treatment is unlikely. As described in the literature, in some selected cases, peptide receptor radionuclide therapy (PRRT) may be used as a first-line/neoadjuvant therapy that allows further successful surgery. Such treatment may enable a reduction of total tumor burden or allow a radical treatment which improves the final outcomes. AIM: This study aims to assess whether neoadjuvant PRRT could be a treatment option for patients with initially unresectable NETs. METHODS: Among the group of 114 patients treated with PRRT between the years 2005 and 2020, in 32 cases, it was the first-line therapy, mainly due to massive disease burden at the time of diagnosis. Among them, nine patients received PRRT as the first-line treatment due to the primary inoperable tumors with the intention of preoperative reduction of the tumor size in order to allow for a surgical treatment. RESULTS: Neoadjuvant PRRT enabled surgery in four out of nine (45%) patients. Finally, in two out of four cases, the goal (radical surgery) has been achieved. CONCLUSION: PRRT may be considered not only as a palliative but also as a neoadjuvant therapy in advanced, somatostatin-positive NETs that were initially inoperable.

Clinical challenges and dilemmas in the management of advanced pancreatic neuroendocrine tumour - the first manifestation of von Hippel-Lindau disease in a young patient.

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Efficacy of multimodal anticancer therapy in the course of pancreatic neuroendocrine carcinoma.

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Clinical Approach to Neuroendocrine Neoplasm Associated With Ovarian Teratoma.

Background: Neuroendocrine neoplasms are a heterogeneous group of cancers that develop from enterochromaffin cells of the diffuse endocrine system, with an increase in incidents over the last years. Ovarian neuroendocrine tumors (NET) are rare neoplasms, comprising 0.1% of all ovarian neoplasms and less than 5% of all neuroendocrine tumors. They may arise alone (as monodermal, specialized teratoma - ovarian carcinoid) or as a part of other ovarian lesion: cystic mature or immature teratomas. Due to the rarity and limited amount of such cases reported in the literature, there is no consensus on diagnostic and therapeutic procedures in this group of patients. Materials and Methods: The group of 10 patients at the age of 19 to 77 years (mean 42.8 ± 17.9), diagnosed with unilateral NET within ovarian teratoma were analyzed. The histopathological type of tumor, progression free survival after surgical treatment and presence of hormonally active syndrome were assessed. Results: 70% (n=7) of patients was diagnosed with mature cystic teratomas containing NET component and 30% (n=3) with monodermal teratoma (strumal carcinoid). All cases of monodermal teratomas were found in women at premenopausal age. Determined Ki67 ranged from 2% to 9%. Ninety percent of lesions (n=9) stained positive for synaptophysin and chromogranin, while markers: CK20, CK7, TTF-1 and CDX2 were negative in all cases, which ruled out their metastatic nature. None of the patients presented with carcinoid syndrome. All followed-up patients remain progression-free, which confirms surgical intervention being a crucial and sufficient method of treatment. Conclusions: The prognosis and clinical behavior of NETs associated with ovarian teratomas are good with long progression-free survival.