Lutetium [177Lu]-DOTA-TATE in gastroenteropancreatic-neuroendocrine tumours: rationale, design and baseline characteristics of the Italian prospective observational (REAL-LU) study.

PURPOSE: Gastroenteropancreatic -neuroendocrine tumours (GEP-NETs) are commonly treated with surgical resection or long-term therapies for tumour growth control. Lutetium [177Lu]-DOTA-TATE was approved for the treatment of GEP-NETs after the phase III NETTER 1trial demonstrated improved progression free survival, objective response rates and health-related quality of life (HRQoL) compared to high-dose somatostatin analogues. No real-world data exist on prescribing habits and clinically significant endpoints for [177Lu]Lu-DOTA-TATE treatment in Italy. REAL-LU is a multicentre, long-term observational study in patients with unresectable/metastatic GEP-NETs progressing on standard therapies in Italian clinical practice. A pre-specified interim analysis was performed at the end of the enrolment period, data from which are described herein. METHODS: Overall duration of REAL-LU will be approximately 48 months, with 12- and 36-month recruitment and follow-up periods, respectively. The primary objective is to evaluate [177Lu]Lu-DOTA-TATE effectiveness in terms of progression-free survival. Secondary objectives include safety, impact on HRQoL, and identification of prognostic factors. This pre-specified interim analysis describes patient profiles, at the end of enrollment, of those prescribed [177Lu]Lu-DOTA-TATE for GEP-NETs in Italy. RESULTS: Among 161 evaluable patients, mean age was 64.7 ± 10.3 years at study entry, 83.8% presented with no clinical signs of disease at physical examination, and most had minor disease symptoms. All patients had metastatic disease, most commonly in the liver (83.9%) with a median of two metastatic sites. In 90.7% of patients, the disease was stage IV, and 68.3% had ≥ 1 target lesion. [177Lu]Lu-DOTA-TATE was prescribed mainly as second-line therapy (61.6%) and following surgery (58.4%). HRQoL assessments revealed high levels of functioning and low levels of symptoms at baseline; 50.0% of patients were symptom-free at study entry. CONCLUSION: The characteristics of patients who received [177Lu]Lu-DOTA-TATE in Italy are similar to those of the GEP-NET population of NETTER 1 with trial but with a higher proportion of patients with a grade 2 (71%). With regard to the tumor grade profile, our study cohort appears to be closer to that of NETTER-2 study population which included patients with G2 or G3 advanced GEP-NETs (i.e. Ki-67 ≥ 10% and ≤ 55%). Further analysis of effectiveness and safety can be anticipated as REAL-LU data mature. STUDY REGISTRATION: ClinicalTrials.gov, NCT04727723; Study Registration Date: 25 January, 2021; https://clinicaltrials.gov/study/NCT04727723?cond=NCT04727723&rank=1.

Prevention of systemic toxicity in hyperthermic isolated lung perfusion using radioisotopic leakage monitoring.

RATIONALE: Hyperthermic isolated lung Perfusion (ILuP) is used to deliver high-dose chemotherapy to pulmonary metastases while sparing systemic toxicity. Accurate leakage monitoring is however necessary. This study aimed to verify the accuracy of radionuclide leakage monitoring in patients undergoing ILuP, by comparing this method with serial blood sampling. METHODS: A total of 15 consecutive ILuP procedures were performed on eleven patients affected by lung metastases from soft tissue sarcoma. After establishing isolated perfusion, erythrocytes of systemic blood (SB) were labelled with 0.2 MBq/kg of 99mTc. The baseline SB counting rate (CR) was assessed using a γ-probe. Subsequently, erythrocytes of the circuit blood (CB) were labelled with 2 Mbq/kg of 99mTc. Radioactivity leakage factor (RLF) was continuously measured using a formula, accounting for CR, systemic/circuit activity ratio and total/systemic volume ratio. The TNF-α concentration in SB and CB was measured by enzymelinked immunosorbent assay (ELISA) throughout the procedure. RESULTS: RLF averaged 2.3 ± 1.5%, while the systemic/circuit TNF-α ratio was 0.05 ± 0.12%. These two indices were strictly correlated in all of the procedures (average Rvalue 0.88 ± 0.07). RLF exceeded 5% during three of 15 procedures, prompting the application of compensatory manoeuvres. ELISA confirmed a marked increase in systemic TNF-α levels in these patients (2.6 ± 3.5 ng/ml). Conversely, patients whose RLF did not exceed the 5% threshold presented a mean TNF-α of 0.02 ± 0.005 ng/ml (p < 0.01). CONCLUSIONS: In patients submitted to ILuP, RLF monitoring is feasible and accurate. Moreover, it grants immediate results, permitting for the adoption of corrective manoeuvres for leakage, thus minimising toxicity.

Doxorubicin Effect on Myocardial Metabolism as a Prerequisite for Subsequent Development of Cardiac Toxicity: A Translational 18F-FDG PET/CT Observation.

The present translational study aimed to verify whether serial 18F-FDG PET/CT predicts doxorubicin cardiotoxicity. Methods: Fifteen athymic mice were treated intravenously with saline (n = 5) or with 5 or 7.5 mg of doxorubicin per kilogram (n = 5 each) and underwent dynamic small-animal PET beforehand and afterward to estimate left ventricular (LV) metabolic rate of glucose (MRGlu). Thereafter, we retrospectively identified 69 patients who had been successfully treated with a regimen of doxorubicin, bleomycin, vinblastine, and dacarbazine for Hodgkin disease (HD) and had undergone 4 consecutive 18F-FDG PET/CT scans. Volumes of interest were drawn on LV myocardium to quantify mean SUV. All patients were subsequently interviewed by telephone (median follow-up, 30 mo); 36 of them agreed to undergo electrocardiography and transthoracic echocardiography. Results: In mice, LV MRGlu was 17.9 ± 4.4 nmol × min-1 × g-1 at baseline. Doxorubicin selectively and dose-dependently increased this value in the standard-dose (27.9 ± 9 nmol × min-1 × g-1, P < 0.05 vs. controls) and high-dose subgroups (37.2 ± 7.8 nmol × min-1 × g-1, P < 0.01 vs. controls, P < 0.05 vs. standard-dose). In HD patients, LV SUV showed a progressive increase during doxorubicin treatment that persisted at follow-up. New-onset cardiac abnormalities appeared in 11 of 36 patients (31%). In these subjects, pretherapy LV SUV was markedly lower with respect to the remaining patients (1.53 ± 0.9 vs. 3.34 ± 2.54, respectively, P < 0.01). Multivariate analysis confirmed the predictive value of baseline LV SUV for subsequent cardiac abnormalities. Conclusion: Doxorubicin dose-dependently increases LV MRGlu, particularly in the presence of low baseline 18F-FDG uptake. These results imply that low myocardial 18F-FDG uptake before the initiation of doxorubicin chemotherapy in HD patients may predict the development of chemotherapy-induced cardiotoxicity, suggesting that prospective clinical trials are warranted to test this hypothesis.

Baseline and ongoing PET-derived factors predict detrimental effect or potential utility of 18F-FDG PET/CT (FDG-PET/CT) performed for surveillance in asymptomatic lymphoma patients in first remission.

PURPOSE: To identify both clinical and FDG PET/CT-derived factors predicting the occurrence of relapse, or conversely, the likelihood of false positive findings in surveillance FDG-PET/CT studies (PETsv). METHODS: The study included 149 asymptomatic patients with Hodgkin's lymphoma (HL) (n = 55) or diffuse large B cell lymphoma (DLBCL) (n = 94) in first remission. PETSv studies were performed 12, 18, 24 and 36 months thereafter. Logistic regression analysis was performed to identify clinical and imaging-derived predictors of either PET-detected relapse or false-positive (FP) results. Tested clinical variables were: 1) age, 2) HL vs. DLBCL, 3) stage of disease, 4) bulky disease, 5) previous radiotherapy. PET/CT-derived variables were: 1) maximum standardized uptake value at baseline, 2) size-incorporated maximum standardized uptake value (SIMaxSUV) at baseline, 3) positive interim PET(PET-2), 4) presence of hot spots likely to be unrelated to the disease in final PET, 5) residual non-FDG avid mass. RESULTS: Accuracy was 88 % for PETsv1, 95 % for PETsv2, 95 % for PETsv3 and 91 % for PETsv4. However, PPV was relatively low in all PETsv. Best predictors of relapse were result of interim PET, HL versus NHL type, SIMaxSUV, age ≥ 60. Best predictors of FP were previous radiotherapy and hot spots unrelated to the disease in final PET. CONCLUSIONS: The present study confirms the need of restricting the use of surveillance PET/CT to patients at high risk of relapse. Information derived from PET/CT performed at baseline (metabolic disease burden), in the course (PET2) and at the end of therapy (unrelated hot spots) can help to select high-risk patients and also to identify patients more likely to present equivocal findings at PETsv.

Clinical efficacy of radioiodine therapy in multinodular toxic goiter, applying an implemented dose calculation algorithm.

Radioiodine is a common therapeutic option for Multinodular Toxic Goiter (MTG). We evaluated an algorithm for personalized radioiodine activity calculation. Ninety-three (28 male, 65 female; 43-84 years) patients with MTG eligible for radioiodine treatment (131I-iodide) were studied. The quantity of 131I-iodide to be administered was estimated by Thyroid Volume Reduction (TVR) algorithm, developed for Graves' disease. It takes into account 131I uptake, its effective half-life (T1/2eff), thyroid volume, and its expected reduction during treatment. A comparison with the activity calculated by other dosimetric protocols and the "fixed" activity method was performed. 131I uptake was measured by external counting, thyroid volume by ultrasonography (US), thyroid stimulating hormone (TSH), and thyroid hormones by standard immunometric methods. In a follow-up of 6-120 months, remission of hyperthyroidism after a single 131I-iodide treatment was observed in 76 patients (64 euthyroid, 12 hypothyroid). The thyroid volume reduction observed by US after the treatment fairly correlated with what predicted by our model; T1/2eff was highly variable and critically affected dose calculation. The administered activities (median 526 MBq, range 156-625 MBq) were slightly lower than the "fixed" activities (600 MBq) and with respect to the other protocols' prescriptions (-15/38%); the median 131I activity administered to relapsed patients (605 MBq) was significantly greater (P=0.01) with respect to the dose administered to cured patients (471 MBq). Our study shows that an effective cure of MTG can be obtained with relatively low 131I activities and probably with a relatively low incidence of hypothyroidism, using TVR method.