18F-fluorocholine PET/CT detects parathyroid gland hyperplasia as well as adenoma: 401 PET/CTs in one center.

BACKGROUND: During the past decade, 18F-fluorocholine (FCH) PET/CT has been continuously performed at Tenon Hospital (Paris, France) for the detection of hyperfunctioning parathyroid glands (PT). METHODS: A cohort of 401 patients, deliberately referred for HPT since September 2012, has been analyzed. The aim of this real-life retrospective study was to determine the diagnostic utility of FCH in this setting, overall and in subgroups according to the type of hyperparathyroidism (HPT), the context of FCH in the imaging work-up and in the patient's history: initial imaging or persistence or recurrence after previous parathyroidectomy (PTX). The influence of the histologic type of resected PTs, hyperplasia or adenoma, on the preoperatory detection on FCH PET/CT has been studied as well. RESULTS: Four hundred one FCH PET/CTs were included in the cohort, performed in 323 patients with primary HPT (pHPT), including 18 with familial HPT (fHPT), and in 78 patients with secondary renal HPT (rHPT). The overall positivity rate in the 401 FCH PET/CTs was 73%. The PTX rate was twice greater in patients whose FCH PET/CT was positive than negative (73% vs. 35%). Abnormal PT(s) were pathology proven in 214 patients: only hyperplastic gland(s) in 75 cases and at least one adenoma in 136 cases; FCH PET/CT sensitivity was 89% and 92%, respectively. Similarly, there was no significant difference in patient-based sensitivity whether FCH PET/CT was performed as 1st line or later in the imaging work-up, or indicated for initial imaging or for suspicion of persistent or recurrent HPT. Gland-based sensitivity was significantly lower for hyperplasia than for adenoma (72% and 86%, respectively). The lowest gland-based sensitivity value was 65%, observed in case of hyperplasia and when FCH was performed late in the imaging work-up. FCH PET/CT correctly showed multiglandular HPT (MGD) in 36/61 proven cases, 59%. Results of ultrasonography (US) and 99mTc-sestaMIBI (MIBI) imaging were available in 346 and 178 patients, respectively. For both modalities, the corresponding sensitivity values were significantly less than those of FCH PET/CT (e.g., overall gland-based sensitivity 78% for FCH, 45% for US, 30% for MIBI) and MGD was detected in 32% of cases by US and 15% by MIBI. CONCLUSIONS: Although FCH PET/CT has been performed since 2017 as 1st line imaging for HPT at Tenon Hospital (Paris, France), a large majority of patients underwent prior US and/or MIBI in their preoperative work-up. Therefore, a selection bias is very likely, as most patients referred to FCH PET/CT had non-conclusive or discordant results of US and MIBI, explaining the low performance of those modalities in the present cohort compared to published results. Nevertheless, the superiority of FCH PET/CT over US and MIBI in detecting abnormal PTs reported in various comparative studies is definitely confirmed in this larger real-life cohort. The detection with FCH PET/CT of hyperplastic PTs was somewhat lower than that of adenomas but was better than using US or MIBI. The present results lead to recommend FCH PET/CT as the first line imaging modality in HPT when it is widely available or, if less available, at least in HPT with predominance of hyperplasia and/or MGD.

Role of 68Ga-DOTATOC PET/CT in Insulinoma According to 3 Different Contexts: A Retrospective Study.

OBJECTIVE: The aim of this study was to assess the performance of 68Ga-DOTATOC PET/CT in the detection and extension of insulinomas according to 3 different contexts: sporadic benign, sporadic metastatic, and multiple endocrine neoplasia type 1 (MEN1). PATIENTS AND METHODS: The data of 71 adult patients who underwent 68Ga-DOTATOC PET/CT for suspected or confirmed sporadic insulinoma, suspicion of insulinoma in the context of MEN1, follow-up of metastatic insulinoma, or suspicion of recurrence of insulinoma were retrospectively analyzed. Pathological examination or strong clinical and biological findings were used as standards of truth. RESULTS: For the assessment of a confirmed sporadic insulinoma in 17 patients, the sensitivity of SR-PET was 75%, including 2 patients for whom metastatic lesions had been revealed by SR-PET. For 35 patients with a suspicion of insulinoma, the sensitivity was 39%. In 10 patients followed up for metastatic insulinoma, the sensitivity was 100%. For 5 patients with a history of MEN1, interpretation of SR-PET was difficult, as 3 of them presented with multiple pancreatic uptake foci. The global sensitivity of SR-PET in all insulinomas excluding those with a MEN1 story was 64% (100% for metastatic insulinomas, 62% for benign insulinomas), with a specificity of 89%. CONCLUSIONS: 68Ga-DOTATOC PET/CT is a useful examination tool for the assessment of insulinomas in selected contexts, with very high performance for the detection and extension workup of metastatic insulinomas and high specificity for the detection of sporadic benign insulinomas. The examination should be completed with GLP-1 receptor PET when it is negative or in a MEN1 context.

Multiple endocrine neoplasia type 1 or 4: detection of hyperfunctioning parathyroid glands with 18F-fluorocholine PET/CT. Illustrative cases and pitfalls.

18F-fluorocholine (FCH) PET/CT is now well established to detect the hyperfunctioning parathyroid glands (HFPTG) in a case of sporadic primary hyperparathyroidism (pHPT), but only limited evidence is available about the utility of FCH PET/CT to detect the HFPTG in patients with multiple endocrine neoplasia (MEN) type 1 or 4. The pHPT in this context frequently consists in a multiglandular disease with small hyperplastic glands rather than adenomas, which is challenging for imaging modalities. The data of patients with MEN1 or MEN4 after parathyroidectomy referred to FCH PET/CT for presurgical localization of HFPTG were retrospectively reviewed, including follow-up after parathyroidectomy, in search for diagnostic performance and for potential pitfalls. In the present cohort, 16 patients referred to FCH PET/CT as part of their initial pHPT work-up were subsequently operated, 44 abnormal parathyroid glands (PT) were resected, of which 32 (73%) had been detected on FCH PET/CT and 2 considered as equivocal foci. Nine patients referred to FCH PET/CT for recurrent pHPT who were subsequently operated, 14 abnormal PT were resected, all had been detected on FCH PET/CT. FCH PET/CT permitted a unilateral approach for PTx in 4 of them. In one patient with MEN4 and pHPT, the HFPTG could not be visualized on FCH PET/CT but was localized by ultrasonography. Several causes of false positive or false negative results, incidental finding and pitfalls are listed and discussed. FCH PET/CT has a positive benefit/risk ratio in the detection of HFPTG in case of MEN1 (the data in MEN4 being currently very limited) with the most effective detection rate of current imaging modalities for HFPTG, few pitfalls, and an adequate impact on patient management compared to sesta MIBI SPECT and ultrasonography.

Comparison of 18F-sodium fluoride PET/CT, 18F-fluorocholine PET/CT and diffusion-weighted MRI for the detection of bone metastases in recurrent prostate cancer: a cost-effectiveness analysis in France.

BACKGROUND: The diagnostic performance of 18F-sodium fluoride positron emission tomography/computed tomography (PET/CT) (NaF), 18F-fluorocholine PET/CT (FCH) and diffusion-weighted whole-body magnetic resonance imaging (DW-MRI) in detecting bone metastases in prostate cancer (PCa) patients with first biochemical recurrence (BCR) has already been published, but their cost-effectiveness in this indication have never been compared. METHODS: We performed trial-based and model-based economic evaluations. In the trial, PCa patients with first BCR after previous definitive treatment were prospectively included. Imaging readings were performed both on-site by local specialists and centrally by experts. The economic evaluation extrapolated the diagnostic performances of the imaging techniques using a combination of a decision tree and Markov model based on the natural history of PCa. The health states were non-metastatic and metastatic BCR, non-metastatic and metastatic castration-resistant prostate cancer and death. The state-transition probabilities and utilities associated with each health state were derived from the literature. Real costs were extracted from the National Cost Study of hospital costs and the social health insurance cost schedule. RESULTS: There was no significant difference in diagnostic performance among the 3 imaging modalities in detecting bone metastases. FCH was the most cost-effective imaging modality above a threshold incremental cost-effectiveness ratio of 3000€/QALY when imaging was interpreted by local specialists and 9000€/QALY when imaging was interpreted by experts. CONCLUSIONS: FCH had a better incremental effect on QALY, independent of imaging reading and should be preferred for detecting bone metastases in patients with biochemical recurrence of prostate cancer. TRIAL REGISTRATION: NCT01501630. Registered 29 December 2011.

68Ga-PSMA-11 PET/CT in restaging castration-resistant nonmetastatic prostate cancer: detection rate, impact on patients' disease management and adequacy of impact.

We aimed to evaluate the impact of prostate-specific membrane antigen ligand labelled with gallium-68 (PSMA-11) PET/CT in restaging patients with castration-resistant nonmetastatic prostate cancer (PCa). Thirty patients were included. At least one malignant focus was found in 27/30 patients (90%). The PSMA-11 PET/CT positivity rate in patients whose prostate-specific antigen serum level (PSA) was greater than 2 ng/ml was 100% (20/20), significantly superior to that of patients whose PSA was less than 2 ng/ml (7/10 = 70%). Six patients (20%) were categorized as oligometastatic (≤3 metastatic foci). Based on the 17 patients for whom a standard of truth was feasible, the overall sensitivity and specificity of PSMA-11 PET/CT in detecting residual disease in castration-resistant PCa patients were 87% and 100% respectively. PSMA-11 PET/CT impacted patients' disease management in 70% of cases, 60% of case when PSA was less than 2 ng/ml. This management was considered as adequate in 91% of patients. PSMA-11 PET/CT appeared to be effective in restaging patients with castration-resistant nonmetastatic PCa. PSMA-11 PET/CT should be considered as a replacement for bone scans under these conditions.

Impact of sodium 18F-fluoride PET/CT, 18F-fluorocholine PET/CT and whole-body diffusion-weighted MRI on the management of patients with prostate cancer suspicious for metastasis: a prospective multicentre study.

PURPOSE: To compare the impact of 18F-sodium-fluoride (NaF) PET/CT, 18F-fluorocholine (FCH) PET/CT and diffusion-weighted whole-body MRI (DW-MRI) on the management of patients with prostate cancer (PCa) suspicious for distant metastasis. METHODS: Prostate cancer patients were prospectively included between December 2011 and August 2014 and benefited from these three whole-body imaging (WBI) modalities within 1 month in addition to the standard PCa workup. Management was prospectively decided by clinicians during two multidisciplinary meetings, before and after the whole-body imaging workup. Rates of induced changes of whole-body imaging modalities were compared by Cochran's Q test. RESULTS: One-hundred-one patients (27 at staging, 59 at first biochemical recurrence (BCR) and 15 at first episode of rising serum level of prostate-specific antigen during androgen-deprivation therapy) were included. The overall rate of management changes was 52%: 29% as a consequence of WBI, higher for FCH-PET/CT than for NaF-PET/CT or DW-MRI (p < 0.0001) and highest (41%) for FCH-PET/CT at BCR. Actual management was adequate in all patients but two. CONCLUSIONS: Whole-body imaging induced a change in management in approximately a third of PCa patients suspicious for metastasis. The impact rate was determined to be greatest at first BCR using FCH-PET/CT. NaF-PET/CT and DW-MRI seemed less useful in this context.