18 F-FET PET/CT in Calcifying Pseudoneoplasm of the Neuraxis : First Case.

ABSTRACT: A 66-year-old man has been treated in a psychiatric department for 4-5 years for a depressive syndrome, which is associated with poor motor initiative, confusional state, and dysosmia. Dynamic 18 F-FET PET/CT showed only faint uptake of radiotracer just above the background on the left frontal calcific lesion. The time-activity curve of the neoplasms showed a descending pattern. After a left fronto-orbitary minicraniotomy surgery, histology examination concluded for a rare calcifying pseudoneoplasm of the neuraxis (CAPNON). To our knowledge, no data are available on the metabolic behavior of CAPNON in 18 F-FET PET/CT. This case highlighted that a faint uptake and descending pattern on dynamic 18 F-FET PET/CT may be helpful in suspected CAPNON before surgery.

Can Baseline [18F]FDG PET/CT Predict Response to Immunotherapy After 6 Months and Overall Survival in Patients with Lung Cancer or Malignant Melanoma? A Multicenter Retrospective Study.

Aim: To assess the role of baseline 18F-fluorodeoxyglucose ([18F]FDG)-positron emission tomography/computed tomography (PET/CT) in predicting response to immunotherapy after 6 months and overall survival (OS) in patients with lung cancer (LC) or malignant melanoma (MM). Materials and Methods: Data from a multicenter, retrospective study conducted between March and November 2021 were analyzed. Patients >18 years old with a confirmed diagnosis of LC or MM, who underwent a baseline [18F]FDG-PET/CT within 1-2 months before starting immunotherapy and had a follow-up of at least 12 months were included. PET scans were examined visually and semiquantitatively by physicians at peripheral centers. The metabolic tumor burden (number of lesions with [18F]FDG-uptake) and other parameters were recorded. Clinical response was assessed at 3 and 6 months after starting immunotherapy, and OS was calculated as the time elapsing between the PET scan and death or latest follow-up. Results: The study concerned 177 patients with LC and 101 with MM. Baseline PET/CT was positive in primary or local recurrent lesions in 78.5% and 9.9% of cases, in local/distant lymph nodes in 71.8% and 36.6%, in distant metastases in 58.8% and 84%, respectively, in LC and in MM patients. Among patients with LC, [18F]FDG-uptake in primary/recurrent lung lesions was more often associated with no clinical response to immunotherapy after 6 months than in cases without any tracer uptake. After a mean 21 months, 46.5% of patients with LC and 37.1% with MM had died. A significant correlation emerged between the site/number of [18F]FDG foci and death among patients with LC, but not among those with MM. Conclusions: In patients with LC who are candidates for immunotherapy, baseline [18F]FDG-PET/CT can help to predict response to this therapy after 6 months, and to identify those with a poor prognosis based on their metabolic parameters. For patients with MM, there was only a weak correlation between baseline PET/CT parameters, response to therapy, and survival.

Recurrent parathyromatosis in a patient with concomitant MEN1 and CASR gene alterations: Clinical management of a case report and literature review.

Introduction: Parathyromatosis is a rare cause of primitive hyperparathyroidism characterized by the presence of numerous parathyroid tissue foci in the neck/mediastinum, due to hyperplasia of parathyroid embryologic residues (primary-form) or to local parathyroid tissue implantation (secondary-form). 63 cases have been described in the literature. In our patient parathyromatosis was due to a combination of two mutations. Case report: A 36-years-old woman was diagnosed with osteoporosis secondary to primary hyperparathyroidism. Subsequent right parathyroidectomy showed a parathyroid adenoma. The follow-up was negative but after 10 years she had a relapse. The genetic screening showed a rare intronic mutation of the MEN1 gene and a heterozygous mutation never described in exon 8 of the CASR gene, coding for the calcium receptor. Calcemia and PTH increased over the years with the onset of nephrocalcinosis and the worsening of osteoporosis despite the therapy with Cinacalcet, bisphosphonates and Vitamin D. She had therefore two additional surgical procedures (parathyroid tissue without malignancy). At follow-up she showed elevated levels of PTH (>1000 pg/ml) and calcium (11.2 mg/dl) and CT scans multiple subcentimetric nodules in the neck/upper mediastinum. Since the 68Ga-DOTATATE showed an increased uptake in the neck/mediastinum, lanreotide was added. After two months there was a significant biochemical response but, unfortunately, after six months, the patient showed a new worsening. Conclusions: a rare case of parathyromatosis due to a combination of two genetic alterations never described. The main issues concern the diagnosis and the radical treatment. Somatostatin analogues may have a useful role in both diagnosis and therapy.

ITA-IMMUNO-PET: The Role of [18F]FDG PET/CT for Assessing Response to Immunotherapy in Patients with Some Solid Tumors.

AIM: To examine the role of [18F]FDG PET/CT for assessing response to immunotherapy in patients with some solid tumors. METHODS: Data recorded in a multicenter (n = 17), retrospective database between March and November 2021 were analyzed. The sample included patients with a confirmed diagnosis of a solid tumor who underwent serial [18F]FDG PET/CT (before and after one or more cycles of immunotherapy), who were >18 years of age, and had a follow-up of at least 12 months after their first PET/CT scan. Patients enrolled in clinical trials or without a confirmed diagnosis of cancer were excluded. The authors classified cases as having a complete or partial metabolic response to immunotherapy, or stable or progressive metabolic disease, based on a visual and semiquantitative analysis according to the EORTC criteria. Clinical response to immunotherapy was assessed at much the same time points as the serial PET scans, and both the obtained responses were compared. RESULTS: The study concerned 311 patients (median age: 67; range: 31-89 years) in all. The most common neoplasm was lung cancer (56.9%), followed by malignant melanoma (32.5%). Nivolumab was administered in 46.3%, and pembrolizumab in 40.5% of patients. Baseline PET and a first PET scan performed at a median 3 months after starting immunotherapy were available for all 311 patients, while subsequent PET scans were obtained after a median 6, 12, 16, and 21 months for 199 (64%), 102 (33%), 46 (15%), and 23 (7%) patients, respectively. Clinical response to therapy was recorded at around the same time points after starting immunotherapy for 252 (81%), 173 (56%), 85 (27%), 40 (13%), and 22 (7%) patients, respectively. After a median 18 (1-137) months, 113 (36.3%) patients had died. On Kaplan-Meier analysis, metabolic responders on the first two serial PET scans showed a better prognosis than non-responders, while clinical response became prognostically informative from the second assessment after starting immunotherapy onwards. CONCLUSIONS: [18F]FDG PET/CT could have a role in the assessment of response to immunotherapy in patients with some solid tumors. It can provide prognostic information and thus contribute to a patient's appropriate treatment. Prospective randomized controlled trials are mandatory.

A Prospective Observational Study on the Structuring Process and Implementation of a Large Regional, Inter-hospital, Virtual Multidisciplinary Tumor Board on Prostate Cancer.

BACKGROUND/AIM: At present, multidisciplinary tumor boards (MDTB) are considered best practice in oncology. However, web-based virtualization of MDTB may increase participation in meetings, the number of cases discussed, and adherence to guidelines, deliver better treatment, and eventually improve outcomes for patients with prostate cancer. PATIENTS AND METHODS: This is an observational study focused on exploring the structuring process and implementing a multi-institutional virtual MDTB in Sicily, Italy. Other endpoints included the analysis of cooperation between participants, adherence to guidelines, patient outcomes, and patient satisfaction. RESULTS: Overall, 126 patients were referred to the virtual MDTB for a total of 302 cases discussed in an 18-month period. Nearly 45% of cases were referred from general hospitals or tertiary centers, 38% from comprehensive cancer centers, and only 17% from academic ones. Most health professional participants (95%) reported eliminating geographical barriers and consequently reducing costs and saving time as key advantages of virtual meetings over face-to-face ones. Using a specifically designed platform for virtual MDTBs was another excellent point, especially to geolocate clinical trials and time-lapse data storage. The majority of referred patients had stage T 3-4 prostate cancer (79%). Overall, 71% of proposals discussed were approved unchanged, while 19% changed after the virtual MDTB discussion. Debated points were mostly radiologic, surgical, medical, or radiation treatment-related issues. In particular, the prescriptive appropriateness of positron emission tomography with 68Ga-prostatic specific membrane antigen, newer drugs, radiation versus surgical approach, stage T3-4 cases, and adjuvant therapy represented the most debated issues. The proposed diagnostic and/or therapeutic options were controlled for adherence to the guidelines and/or updated scientific evidence. Overall, 98% of approved proposals and changes were in line with the guidelines. Overall, most participants felt virtual MDTB was very useful and case discussions led to a major change of strategy in 19% of cases. CONCLUSION: Virtual MDTBs are a very useful way to achieve best management of prostate cancer while saving time and fostering cooperation.

Prostate Cancer Biochemical Recurrence Resulted Negative on [68Ga]Ga-PSMA-11 but Positive on [18F]Fluoromethylcholine PET/CT.

For prostate cancer (PCa) biochemical recurrence (BCR), the primarily suggested imaging technique by the European Association of Urology (EAU) guidelines is prostate-specific membrane antigen (PSMA) positron emission tomography/computer tomography (PET/CT). Indeed, the increased detection rate of PSMA PET/CT for early BCR has led to a fast and wide acceptance of this novel technology. However, PCa is a very heterogeneous disease, not always easily assessable with the highly specific PSMA PET with around 10% of cases occuring without PSMA expression. In this paper, we present the case of a patient with PCa BCR that resulted negative on [68Ga]Ga-PSMA-11 PET/CT, but positive on [18F]Fluoromethylcholine (Choline) PET/CT.

[68Ga]DOTATOC PET/CT Radiomics to Predict the Response in GEP-NETs Undergoing [177Lu]DOTATOC PRRT: The "Theragnomics" Concept.

Despite impressive results, almost 30% of NET do not respond to PRRT and no well-established criteria are suitable to predict response. Therefore, we assessed the predictive value of radiomics [68Ga]DOTATOC PET/CT images pre-PRRT in metastatic GEP NET. We retrospectively analyzed the predictive value of radiomics in 324 SSTR-2-positive lesions from 38 metastatic GEP-NET patients (nine G1, 27 G2, and two G3) who underwent restaging [68Ga]DOTATOC PET/CT before complete PRRT with [177Lu]DOTATOC. Clinical, laboratory, and radiological follow-up data were collected for at least six months after the last cycle. Through LifeX, we extracted 65 PET features for each lesion. Grading, PRRT number of cycles, and cumulative activity, pre- and post-PRRT CgA values were also considered as additional clinical features. [68Ga]DOTATOC PET/CT follow-up with the same scanner for each patient determined the disease status (progression vs. response in terms of stability/reduction/disappearance) for each lesion. All features (PET and clinical) were also correlated with follow-up data in a per-site analysis (liver, lymph nodes, and bone), and for features significantly associated with response, the Δradiomics for each lesion was assessed on follow-up [68Ga]DOTATOC PET/CT performed until nine months post-PRRT. A statistical system based on the point-biserial correlation and logistic regression analysis was used for the reduction and selection of the features. Discriminant analysis was used, instead, to obtain the predictive model using the k-fold strategy to split data into training and validation sets. From the reduction and selection process, HISTO_Skewness and HISTO_Kurtosis were able to predict response with an area under the receiver operating characteristics curve (AUC ROC), sensitivity, and specificity of 0.745, 80.6%, 67.2% and 0.722, 61.2%, 75.9%, respectively. Moreover, a combination of three features (HISTO_Skewness; HISTO_Kurtosis, and Grading) did not improve the AUC significantly with 0.744. SUVmax, however, could not predict the response to PRRT (p = 0.49, AUC 0.523). The presented preliminary "theragnomics" model proved to be superior to conventional quantitative parameters to predict the response of GEP-NET lesions in patients treated with complete [177Lu]DOTATOC PRRT, regardless of the lesion site.

First case of 18F-choline uptake in acoustic schwannoma after stereotactic radiotherapy.

A 69-year-old male patient, with bilateral hypoacusia and tinnitus, had a diagnosis of left vestibular schwannoma with synchronous meningioma on the left frontal lobe. After partial surgical resection of the acoustic schwannoma, this was followed by stereotactic radiosurgery on the residual lesion. The patient had a metachronous prostate cancer treated with conformal radiotherapy associated to 6 months of hormone therapy with luteinizing hormone/releasing hormone analog. During follow-up, prostate-specific antigen value increased to 0.27 ng/mL and the patient underwent 18F-methylcholine positron emission tomography/computed tomography (18F-choline PET/CT). The whole-body scan demonstrated a focus of increased uptake at level of the left cerebellopontine angle and at the left frontal lobe, corresponding to the known vestibular schwannoma and meningioma. A subsequent brain contrast-enhanced magnetic resonance imaging (MRI) showed an increased dimension of the left cerebellopontine neuroma and dimensional stability of the left frontal meningioma compared with previous MRI of 6 months earlier. To the best of our knowledge, we describe the first case of a 18F-choline PET/CT demonstrating a relapse of a vestibular schwannoma after stereotactic radiotherapy.

Lymphocytic toxicity in patients after peptide-receptor radionuclide therapy (PRRT) with 177Lu-DOTATATE and 90Y-DOTATOC.

PURPOSE: Peptide-receptor radionuclide therapy (PRRT) with somatostatin analogs is an efficient new tool in patients with neuroendocrine tumors, with low risk of toxicity. Since lymphocytes express somatostatin receptors, the aim of this study was to evaluate lymphocytic toxicity after PRRT. METHODS: From May 2005 to May 2007, 16 patients affected by neuroendocrine tumors received PRRT with (90)Y-DOTATOC (9), (177)Lu-DOTATATE (5), or both (2). Absolute count, percentage of leukocytes and lymphocytes, and lymphoid subsets (B, T, and NK) were tested at baseline and until 90 days after treatment. RESULTS: A significant lymphoid toxicity (G2-3), mainly affecting B-cells, was observed. It was particularly evident after (90)Y-DOTATOC. Toxicity resulted in being transient and resolved completely at the end of the follow-up (90 days). CONCLUSION: Lymphocyte toxicity in PRRT is mainly due to the selective targeting on B-cells. The relative sparing of T-lymphocytes could explain the absence of clinical side-effects in these patients, such as increased risk of infections. These findings open interesting perspectives in the treatment of B-cell lymphoproliferative disorders.

The role of dosimetry in the high activity 90Y-ibritumomab tiuxetan regimens: two cases of abnormal biodistribution.

Radioimmunotherapy (RIT) with a commercially available brand of yttrium-90 ((90)Y)-ibritumomab-tiuxetan at the prescribed activity of 14.8 MBq/kg (0.4 mCi/kg) represents a complementary approach in the treatment of resistant/refractory B-cell non-Hodgkin's lymphoma. A trial based on higher activities is ongoing in our institute. In this paper, we report atypical pharmacokinetics and liver uptake in 2 patients. Before RIT, all patients underwent dosimetry with (111)In-ibritumomab-tiuxetan. Imaging data were analyzed to obtain predicted absorbed doses to nontarget organs. Therapy was administered only if a 20-Gy-limit dose to normal organs (except red marrow) was guaranteed. Both patients we describe showed abnormal liver uptake, increasing for 6 days post injection. In patient 1, there was atypical biodistribution in whole-blood images at 16 hours, with a prevalent high liver uptake (45% at 20 hours). Injected activity (IA%) was above 40% at 26 hours in the liver and lower than 60% in the total body. In patient 2, early images showed regular biodistribution. Subsequent images showed progressive increase of liver uptake (above 25% of percent injected activity at 25 hours). Liver-absorbed doses of 51 and 53 Gy, respectively, would have resulted with the administration of the prescribed 56 MBq/kg. Following these dosimetric results, both patients did not receive the planned therapy. These findings support the recommendation to include dosimetry in high-dose RIT.

Peptide receptor radionuclide therapy with (90)Y-DOTATOC in recurrent meningioma.

PURPOSE: Meningiomas are generally benign and in most cases surgery is curative. However, for high-grade histotypes or partially resected tumours, recurrence is fairly common. External beam radiation therapy (EBRT) is usually given in such cases but is not always effective. We assessed peptide receptor radionuclide therapy (PRRT) using (90)Y-DOTATOC in a group of patients with meningioma recurring after standard treatments in all of whom somatostatin receptors were strongly expressed on meningioma cell surfaces. METHODS: Twenty-nine patients with scintigraphically proven somatostatin subtype 2 receptor-positive meningiomas were enrolled: 14 had benign (grade I), 9 had atypical (grade II) and 6 had malignant (grade III) disease. Patients received intravenous (90)Y-DOTATOC for 2-6 cycles for a cumulative dose in the range of 5-15 GBq. Clinical and neuroradiological evaluations were performed at baseline, during and after PRRT. RESULTS: The treatment was well tolerated in all patients. MRI 3 months after treatment completion showed disease stabilization in 19 of 29 patients (66%) and progressive disease in the remaining 10 (34%). Better results were obtained in patients with grade I meningioma than in those with grade II-III, with median time to progression (from beginning PRRT) of 61 months in the low-grade group and 13 months in the high-grade group. CONCLUSION: PRRT with (90)Y-DOTATOC can interfere with the growth of meningiomas. The adjuvant role of this treatment, soon after surgery, especially in atypical and malignant histotypes, deserves further investigation.

Radioembolisation with 90Y-microspheres: dosimetric and radiobiological investigation for multi-cycle treatment.

INTRODUCTION: Radioembolisation with (90)Y-microspheres is a new locoregional treatment of hepatic lesions, usually applied as single cycle. Multi-cycle treatments might be considered as a strategy to improve the risk-benefit balance. With the aim to derive suitable information for patient tailored therapy, available patients' dosimetric data were reviewed according to the linear-quadratic model and converted into biological effective dose (BED) values. Single vs. multi-cycle approaches were compared through radiobiological perspective. MATERIALS AND METHODS: Twenty patients with metastatic lesions underwent radioembolisation. The (90)Y-administered activity (AA) was established in order to respect a precautionary limit dose (40 Gy) for the non-tumoral liver (NTL). BED was calculated setting alpha/beta = 2.5 Gy (NTL), 10 Gy (tumours); T (1/2,eff) = T (1/2,phys) = 64.2 h; T (1/2,rep) = 2.5 h (NTL), 1.5 h (tumours). The BED to NTL was considered as a constraint for multi-cycle approach. The AA for two cycles and the percent variations of AA, tumour dose, BED were estimated. RESULTS: In one-cycle, for a prescribed BED to NTL of 64 Gy (NTL dose = 40 Gy), AA was 1.7 (0.9-3.2) GBq, tumour dose was 130 (65-235) Gy, and tumour BED was 170 (75-360) Gy. Considering two cycles, approximately 15% increase was found for AA and dose to NTL, with unvaried BED for NTL. Tumour dose increase was 20 (10-35) Gy; tumour BED increase was 10 (3-11) Gy. In different protocols allowing 80 Gy to NTL, the BED sparing estimated was approximately 50 Gy (two cycles) and 65 Gy (three cycles). CONCLUSIONS: From a radiobiological perspective, multi-cycle treatments would allow administering higher activities with increased tumour irradiation and preserved radiation effects on NTL. Trials comparing single vs. multiple cycles are suggested.

Timing of examination affects reliability of 99mTc-methoxyisobutylisonitrile SPECT in distinguishing neoplastic from nonneoplastic brain hematomas.

UNLABELLED: 99mTc-methoxyisobutylisonitrile (MIBI) SPECT has been reported to be 100% sensitive and specific in the early differential diagnosis between neoplastic and nonneoplastic intraparenchymal cerebral hemorrhage (ICH), because nonneoplastic ICH does not show 99mTc-MIBI accumulation on SPECT examinations performed within 48 h from the onset of clinical symptoms. The aims of this study were to investigate the behavior of nonneoplastic ICH on more delayed 99mTc-MIBI SPECT examinations and to determine how the timing of examination affects the reliability of 99mTc-MIBI SPECT in differentiating neoplastic from nonneoplastic ICH. METHODS: We prospectively enrolled 32 patients with acute neurologic deterioration caused by nontraumatic ICH. Patients were randomly allocated to 4 groups of 8 patients each. Patients in the first, second, third, and fourth groups underwent 99mTc-MIBI SPECT 2, 5, 10, and 30 d, respectively, after the onset of clinical deterioration. Furthermore, patients in the first group underwent a second (99m)Tc-MIBI SPECT examination at 30 d. 99mTc-MIBI SPECT studies were visually and semiquantitatively evaluated. Patients were followed up to confirm the nonneoplastic etiology of the ICH. RESULTS: Two of the 32 studied patients, 1 in the second and 1 in the fourth group, were excluded because the ICH turned out to be related to a neoplastic lesion. Visual analysis showed no 99mTc-MIBI uptake in any patient studied at 2 d, whereas increased radiotracer uptake was found in 1 (14%) of 7, 5 (62.5%) of 8, and 5 (71%) of 7 patients studied 5, 10, and 30 d, respectively, after clinical deterioration. Moreover, with the semiquantitative analysis, a statistically significant difference was found among 99mTc-MIBI indices in the 4 groups (P = 0.0011). All patients in group 1 showed a significant 99mTc-MIBI accumulation when studied at 30 d. CONCLUSION: Nonneoplastic ICH, showing no 99mTc-MIBI uptake within 2 d, can show 99mTc-MIBI accumulation on more delayed imaging. 99mTc-MIBI SPECT can clearly differentiate between neoplastic and nonneoplastic ICH only during the acute phase. Our findings suggest that examination be performed early after the onset of symptoms and certainly within 5 d.