Normal organ dosimetry for thyroid cancer patients treated with radioiodine as part of the multi-centre multi-national Horizon 2020 MEDIRAD project.

PURPOSE: Dosimetry is rarely performed for the treatment of differentiated thyroid cancer patients with Na[131I]I (radioiodine), and information regarding absorbed doses delivered is limited. Collection of dosimetry data in a multi-centre setting requires standardised quantitative imaging and dosimetry. A multi-national, multi-centre clinical study was performed to assess absorbed doses delivered to normal organs for differentiated thyroid cancer patients treated with Na[131I]I. METHODS: Patients were enrolled in four centres and administered fixed activities of 1.1 or 3.7 GBq of Na[131I]I using rhTSH stimulation or under thyroid hormone withdrawal according to local protocols. Patients were imaged using SPECT(/CT) at variable imaging time-points following standardised acquisition and reconstruction protocols. Whole-body retention data were collected. Dosimetry for normal organs was performed at two dosimetry centres and results collated. RESULTS: One hundred and five patients were recruited. Median absorbed doses per unit administered activity of 0.44, 0.14, 0.05 and 0.16 mGy/MBq were determined for the salivary glands of patients treated at centre 1, 2, 3 and 4, respectively. Median whole-body absorbed doses for 1.1 and 3.7 GBq were 0.05 Gy and 0.16 Gy, respectively. Median whole-body absorbed doses per unit administered activity of 0.04, 0.05, 0.04 and 0.04 mGy/MBq were calculated for centre 1, 2, 3 and 4, respectively. CONCLUSIONS: A wide range of normal organ doses were observed for differentiated thyroid cancer patients treated with Na[131I]I, highlighting the necessity for individualised dosimetry. The results show that data may be collated from multiple centres if minimum standards for the acquisition and dosimetry protocols can be achieved.

RADTHYR: an open-label, single-arm, prospective multicenter phase II trial of Radium-223 for the treatment of bone metastases from radioactive iodine refractory differentiated thyroid cancer.

PURPOSE: This is the first prospective trial evaluating the efficacy of alpha emitter Radium-223 in patients with bone metastases from radioactive iodine (RAI) refractory (RAIR) differentiated thyroid cancer. METHODS: RADTHYR is a multicenter, single-arm prospective Simon two-stage phase II trial (NCT02390934). The primary objective was to establish the efficacy of three administrations of 55 kBq/kg of Radium-223 by 18F-FDG PET/CT according to PERCIST criteria. Secondary objectives were to establish the efficacy of six administrations of Radium-223 by 18F-FDG PET/CT, 99mTc-HMDP bone scan and 18FNa PET/CT, clinical benefits, changes in serum bone markers, thyroglobulin levels, and safety. RESULTS: Ten patients were enrolled between July 2015 and December 2017 (4 M; median age 74 years). Prior to Radium-223 administration, patients received a median RAI cumulative activity of 15 GBq (7.4-35.6), external radiation therapy (n = 9), bone surgery (n = 8), cimentoplasty (n = 5), and cryoablation (n = 2). 18F-FDG PET/CT showed stable disease (SD) in 4/10 and progressive disease (PD) in 6/10 cases after three administrations and SD in 4/10, PD in 5/10 cases, and 1/10 non-evaluable (NE) case after six administrations. After six injections, 99mTc-HMDP bone scan showed SD in 9 cases and was NE in 1 case; 18FNa PET/CT showed SD in 8 cases, partial response (PR) in 1 case, and was NE in 1 case. No significant clinical benefits were reported during the study. A skeletal event occurred in 6 patients (median time without skeletal event of 12.1 months). Seventy-seven adverse events were reported during treatment (7 of grade 3-4). Three patients developed an acute myeloid, a promyelocytic, and a chronic myeloid leukemia after the last Radium-223 administration considered as drug-related. CONCLUSION: The trial was stopped after interim analysis for lack of response of bone metastases from RAIR thyroid cancer to Radium-223. Severe hematological toxicity was observed in patients heavily pretreated with RAI and external radiation. TRIAL REGISTRATION NUMBER: NCT02390934. Registration date 18.03.2015.

Cushing syndrome secondary to ectopic adrenocorticotropic hormone secretion from a Meckel diverticulum neuroendocrine tumor: case report.

BACKGROUND: Ectopic production of adrenocorticotropic hormone (ACTH) by neuroendocrine tumours (NET) is a rare condition, occult presentations often hampering the diagnosis. Although NET are relatively frequent in the ileon and Meckel diverticulum, we describe the first Cushing's syndrome due to ectopic adrenocorticotropic syndrome (CS-EAS) arising from a Meckel diverticulum. CASE PRESENTATION: A 44-year-old man was admitted with recent onset of diabetes, myopathy, edema and hypokalemic metabolic alkalosis consistent with Cushing's syndrome. Both basal and dynamic laboratory evaluation suggested CS-EAS. Laboratory testing also showed high serum levels of chromogranin A (CgA) and urinary 5-hydroxyindoleacetic acid (5HIAA). Pituitary and neck/thorax/abdomen/pelvis imaging proved to be normal, while somatostatin analogue ((99m)Tc-HYNIC-TOC) scintigraphy revealed increased focalized ileum uptake on the right iliac fossa. Pre-operative ketoconazole and sandostatin treatment controlled the hypercortisolism within a month. Pathological analysis of the resected submucosal 1.8 cm tumour of the Meckel diverticulum and a metastatic local lymph node confirmed a well differentiated neuroendocrine tumour (grade I), whereas immunohistochemistry was positive for ACTH, chromogranin A and synaptophysin. Post-operative clinical and biochemical resolution of Cushing's syndrome was followed by normalization of both CgA and 5HIAA, which were maintained at the 6 month follow-up. CONCLUSION: The identification, characterization and follow-up of this rare cause of ectopic ACTH secretion is important in order to assess the long-term prognostic and management.

Testicular histological and immunohistochemical aspects in a post-pubertal patient with 5 alpha-reductase type 2 deficiency: case report and review of the literature in a perspective of evaluation of potential fertility of these patients.

BACKGROUND: Testicular morphology and immunohistochemical studies have never been reported in genetically documented adult patients with 5 alpha-reductase type 2 deficiency (5α-R2 deficiency). CASE PRESENTATION: We describe the testicular histopathology of a 17-year-old XY subject with 5α-R2 deficiency caused by the recurrent homozygous Gly115Asp loss of function mutation of the SRD5A2 gene.We also performed an immunohistochemical analysis in order to further study the relationship between seminiferous tubules structure, Sertoli cell differentiation and androgenic signaling impairment in this case. We thus evaluated the testicular expression of the anti-Müllerian hormone (AMH), androgen receptor (AR) and 3ß-hydroxysteroid dehydrogenase (3ßHSD). Histological analysis revealed a heterogeneous aspect with a majority (92%) of seminiferous tubules (ST) presenting a mature aspect but containing only Sertoli cells and devoid of germ cells and spermatogenesis. Focal areas of immature ST (8%) were also found. Testicular AR and 3ßHSD expression were detected in adult male control, 5α-R2 deficiency and CAIS subjects. However, AMH expression was heterogeneous (detectable only in few AR negative prepubertal ST, but otherwise repressed) in the 5α-R2 deficiency, conversely to normal adult testis in which AMH was uniformly repressed and to an adult CAIS testis in which AMH was uniformly and strongly expressed. CONCLUSION: Intratesticular testosterone can repress AMH by itself, independently of its metabolism into dihydrotestosterone. We also compare our results to the few post pubertal cases of 5α-R2 deficiency with available histological testicular description, reported in the literature. We will discuss these histological findings, in the more general context of evaluating the fertility potential of these patients if they were raised as males and were azoospermic.

Diffuse Bone Uptake of 131 I and Effect on Blood Counts in a Patient With Papillary Thyroid Carcinoma and Chronic Lymphocytic Leukemia.

ABSTRACT: A 57-year-old woman with history of chronic lymphocytic leukemia was referred to our center for adjuvant 131 I therapy following complete thyroidectomy for differentiated thyroid cancer. Posttherapeutic scintigraphy revealed atypical diffuse osteomedullar uptake. A major drop in lymphocyte count was observed, from 117.7 g/L to 4.8 g/L 8 weeks after 131 I therapy. Bone marrow uptake is presumed to be related to tracer sequestration in leukemic cells. White blood cell count normalization suggests a high sensitivity of leukemic cells to beta emission. This scintigraphic pattern may act as a pitfall for nuclear medicine physician.

Evaluation of a blood miRNA/mRNA signature to follow-up Lu-PRRT therapy for G1/G2 intestinal neuroendocrine tumors.

Background: 177Lu-oxodotreotide peptide receptor therapy (LuPRRT) is an efficient treatment for midgut neuroendocrine tumors (NETs) of variable radiological response. Several clinical, biological, and imaging parameters may be used to establish a relative disease prognosis but none is able to predict early efficacy or toxicities. We investigated expression levels for mRNA and miRNA involved in radiosensitivity and tumor progression searching for correlations related to patient outcome during LuPRRT therapy. Methods: Thirty-five patients received LuPRRT for G1/G2 midgut NETs between May 2019 and September 2021. Peripheral blood samples were collected prior to irradiation, before and 48 h after the second and the fourth LuPRRT, and at 6-month follow-up. Multiple regression analyses and Pearson correlations were performed to identify the miRNA/mRNA signature that will best predict response to LuPRRT. Results: Focusing on four mRNAs and three miRNAs, we identified a miRNA/mRNA signature enabling the early identification of responders to LuPRRT with significant reduced miRNA/mRNA expression after the first LuPRRT administration for patients with progressive disease at 1 year (p < 0.001). The relevance of this signature was reinforced by studying its evolution up to 6 months post-LuPRRT. Moreover, nadir absolute lymphocyte count within the first 2 months after the first LuPRRT administration was significantly related to low miRNA/mRNA expression level (p < 0.05) for patients with progressive disease. Conclusion: We present a pilot study exploring a miRNA/mRNA signature that correlates with early hematologic toxicity and therapeutic response 12 months following LuPRRT. This signature will be tested prospectively in a larger series of patients.

Impact of different models based on blood samples and images for bone marrow dosimetry after 177Lu-labeled somatostatin-receptor therapy.

BACKGROUND: Peptide receptor radionuclide therapy with 177Lu-DOTATATE is a recognized option for treating neuroendocrine tumors and has few toxicities, except for the kidneys and bone marrow. The bone marrow dose is generally derived from a SPECT/CT image-based method with four timepoints or from a blood-based method with up to 9 timepoints, but there is still no reference method. This retrospective single-center study on the same cohort of patients compared the calculated bone marrow dose administered with both methods using mono, bi- or tri-exponential models. For the image-based method, the dose was estimated using Planetdose© software. Pearson correlation coefficients were calculated. We also studied the impact of late timepoints for both methods. RESULTS: The bone marrow dose was calculated for 131 treatments with the blood-based method and for 17 with the image-based method. In the former, the median absorbed dose was 15.3, 20.5 and 28.3 mGy/GBq with the mono-, bi- and tri-exponential model, respectively. With the image-based method, the median absorbed dose was 63.9, 41.9 and 60.8 with the mono-, bi- and tri-exponential model, respectively. Blood samples after 24h post-injection did not evidence any change in the absorbed bone marrow dose with the bi-exponential model. On the contrary, the 6-day post-injection timepoint was more informative with the image-based model. CONCLUSION: This study confirms that the estimated bone marrow dose is significantly lower with the blood-based method than with the image-based method. The blood-based method with a bi-exponential model proved particularly useful, without the need for blood samples after 24h post-injection. Nevertheless, this blood-based method is based on an assumption that needs to be more validated. The important difference between the two methods does not allow to determine the optimal one to estimate the true absorbed dose and further studies are necessary to compare with biological effects.

Insertion of synthetic lesions on patient data: a method for evaluating clinical performance differences between PET systems.

BACKGROUND: Performance assessment of positron emission tomography (PET) scanners is crucial to guide clinical practice with efficiency. We have already introduced and experimentally evaluated a simulation method allowing the creation of a controlled ground truth for system performance assessment. In the current study, the goal was to validate the method using patient data and demonstrate its relevance to assess PET performances accuracy in clinical conditions. METHODS: Twenty-four patients were recruited and sorted into two groups according to their body mass index (BMI). They were administered with a single dose of 2 MBq/kg 18F-FDG and scanned using clinical protocols consecutively on two PET systems: the Discovery-IQ (DIQ) and the Discovery-MI (DMI). For each BMI group, sixty synthetic lesions were dispatched in three subgroups and inserted at relevant anatomical locations. Insertion of synthetic lesions (ISL) was performed at the same location into the two consecutive exams. Two nuclear medicine physicians evaluated individually and blindly the images by qualitatively and semi-quantitatively reporting each detected lesion and agreed on a consensus. We assessed the inter-system detection rates of synthetic lesions and compared it to an initial estimate of at least 1.7 more targets detected on the DMI and the detection rates of natural lesions. We determined the inter-reader variability, evaluated according to the inter-observer agreement (IOA). Adequate inter-reader variability was found for IOA above 80%. Differences in standardized uptake value (SUV) metrics were also studied. RESULTS: In the BMI ≤ 25 group, the relative true positive rate (RTPR) for synthetic and natural lesions was 1.79 and 1.83, respectively. In the BMI > 25 group, the RTPR for synthetic and natural lesions was 2.03 and 2.27, respectively. For each BMI group, the detection rate using ISL was consistent to our estimate and with the detection rate measured on natural lesions. IOA above 80% was verified for any scenario. SUV metrics showed a good agreement between synthetic and natural lesions. CONCLUSIONS: ISL proved relevant to evaluate performance differences between PET scanners. Using these synthetically modified clinical images, we can produce a controlled ground truth in a realistic anatomical model and exploit the potential of PET scanner for clinical purposes.

RadioLigand Therapy with [177Lu]Lu-PSMA-617 for Salivary Gland Cancers: Literature Review and First Compassionate Use in France.

Salivary gland cancers are rare tumors comprising a large group of heterogeneous tumors with variable prognosis. Their therapeutic management at a metastatic stage is challenging due to the lack of therapeutic lines and the toxicity of treatments. [177Lu]Lu-PSMA-617 (prostate-specific membrane antigen) is a vectored radioligand therapy (RLT) initially developed to treat castration-resistant metastatic prostate cancer with encouraging results in terms of efficacy and toxicity. Many malignant cells could be treated with [177Lu]Lu-PSMA-617 as long as they express PSMA as a consequence of androgenic pathway activation. RLT may be used when anti-androgen hormonal treatment has failed, particularly in prostate cancer. [177Lu]Lu-PSMA-617 has been proposed in certain salivary gland cancers, though the expression of PSMA is demonstrated by a significant uptake using [68Ga]Ga-PSMA-11 PET scan. This theranostic approach could be a new therapeutic option, warranting prospective investigation in a larger cohort. We review the literature on this subject and offer a clinical illustration of compassionate use in France as a perspective for administering [177Lu]Lu-PSMA-617 in salivary gland cancer.

Healthy birth after testicular extraction of sperm and ICSI from an azoospermic man with mild androgen insensitivity syndrome caused by an androgen receptor partial loss-of-function mutation.

CONTEXT: The androgen receptor (AR) is essential for the development and maintenance of the male phenotype, and for spermatogenesis. Mutations in the AR gene cause a wide variety of androgen insensitivity syndromes (AIS), ranging from complete feminization to phenotypic males with infertility. OBJECTIVE: We report the first birth achieved after intracytoplasmic sperm injection (ICSI) with sperm from an azoospermic man with an AR mutation associated with mild AIS (MAIS). PATIENTS AND METHODS: A couple with primary infertility was referred to our centre. The man had azoospermia with testicular hypotrophy and an undervirilized phenotype despite a normal plasma testosterone level. His androgen sensitivity index and serum anti-mullerian hormone (AMH) levels were elevated, pointing to AIS. Molecular analysis of the AR gene revealed a point mutation resulting in an F754S substitution (renumbered F755S in the 2012 McGill University AR gene database), in the ligand-binding domain of the protein, and further analysis indicated impaired receptor function. RESULTS: After genetic counselling of the couple, oocytes were retrieved after controlled ovarian hyperstimulation, and sperm were obtained simultaneously by testicular extraction for ICSI. Nine embryos were obtained. Two were transferred and two were suitable for cryopreservation. A pregnancy was obtained and a healthy girl, carrying the F754S AR mutation, was born at 37 weeks of gestation. AR and AMH were detected by immunohistochemistry in the patient's testicular specimens. AMH immuno-staining was intense in tubules without spermatogenesis and weak in those with ongoing spermatogenesis. CONCLUSION: A healthy child can be obtained by testicular extraction and ICSI despite azoospermia in MAIS. The parents must be informed of the X-linked transmission of the mutation to their descendants. The relationship between AR signalling, testicular AMH expression and spermatogenesis in this patient is discussed.

Receptor radionuclide targeting for neuroendocrine tumors (NET) diagnostic and therapy.

Neuroendocrine tumors (NET) represent a heterogeneous group of tumors originating from cells of neuroendocrine origin, which express somatostatin receptors (SSTR). This property allowed the successful development of radionuclides for diagnostic and peptide radionuclide radiation therapy (PRRT). This is the paradigm for the theragnostic concept in NET personalized medicine. The only phase III study to date (NETTER-1) clearly demonstrated the ability of 177Lutetium-based PRRT to improve progression-free survival in advanced intestinal NETs. In clinical practice, the indications are limited to G1-G2 well-differentiated NETs with high expression of SSTR. NETs with a low tumor burden and slow progression are probably the optimal indication. This treatment is now available in France. However, its precise position in the treatment algorithm remains to be explored. We provide an overview of receptor radionuclide utilization and mechanism in diagnostic and pretherapeutic imaging and we focus on PRRT for endocrine tumors.

Diagnosis of an intestinal mucormycosis 'fungus ball' located with PET/CT with [18F] FDG-PET/CT.

Mucormycosis is a life-threatening infection with most commonly rhino-orbital-cerebral and pulmonary syndromes that mostly occurs in immunocompromised patients. FDG-PET/CT emerged as a sensitive non-invasive tool to identify systemic mucormycosis. We present a 59-year-old woman for whom a PET/CT with 18F-FDG was performed in search of a primary location of mucormycosis with non-contributive conventional workup. A large left abdominal mass was seen, compatible with a fungus ball, with intense parietal uptake and without any central uptake. The localization of the infection provided a target for surgery and permitted to adapt the therapeutic strategy. After resection, the final diagnosis was consistent with mucormycosis. To our knowledge, this is the first report of a PET/CT image with FDG showing an intestinal fungus ball. PET/CT with 18F-FDG may contribute to the management of patients with fungal infections of unknown origin.

Ligand-dependent stabilization of androgen receptor in a novel mouse ST38c Sertoli cell line.

Mature Sertoli cells (SC) are critical mediators of androgen regulation of spermatogenesis, via the androgen receptor (AR) signaling. Available immortalized SC lines loose AR expression or androgen responsiveness, hampering the study of endogenous AR regulation in SC. We have established and characterized a novel clonal mouse immortalized SC line, ST38c. These cells express some SC specific genes (sox9, wt1, tjp1, clu, abp, inhbb), but not fshr, yet more importantly, maintain substantial expression of endogenous AR as determined by PCR, immunocytochemistry, testosterone binding assays and Western blots. Microarrays allowed identification of some (146) but not all (rhox5, spinlw1), androgen-dependent, SC expressed target genes. Quantitative Real-Time PCR validated regulation of five up-regulated and two down-regulated genes. We show that AR undergoes androgen-dependent transcriptional activation as well as agonist-dependent posttranslational stabilization in ST38c cells. This cell line constitutes a useful experimental tool for future investigations on the molecular and cellular mechanisms of androgen receptor signaling in SC function.

Additional diagnostic value of hybrid SPECT-CT systems imaging in patients with differentiated thyroid cancer.

AIM: : Nuclear medicine has entered a new era of multimodality imaging. Single-photon emission computed tomography/computed tomography (SPECT/CT) hybrid cameras are relatively new diagnostic tools that have been widely adopted and are present in most nuclear medicine units. SPECT/CT instruments allow functional and morphologic images to be acquired as superimposed (fusion images) in a single session. METHODS: The integration of CT enables better characterization of functional abnormalities identified on planar and SPECT scintigraphy by offering structural information. It thus highly improves accuracy compared with conventional scintigraphy. RESULTS AND CONCLUSIONS: The combination of functional information and anatomic localization has the potential to influence medical practice with newer imaging algorithms. This review presents the current evidence and potential indications of SPECT/CT imaging in the initial staging, treatment, and follow-up of patients with differentiated thyroid cancer.

Familial isolated primary hyperparathyroidism due to HRPT2 mutation.

Primary hyperparathyroidism is a common endocrine disorder that is mostly caused by solitary tumors within the parathyroid glands. Characterized by early debut and higher frequency of multiple parathyroid masses, familial forms of primary hyperparathyroidism are caused by the already known mutations of: menin (MEN1 syndrome), RET proto-oncogene (MEN2 syndrome), HRPT2-parafibromin (hyperparathyroidism-jaw tumor syndrome), calcium sensing receptor gene (familial hypocalciuric hypercalcemia). A specific mutation in FIHP has not been identified in the majority of affected families. Recent studies revealed menin, HRPT2 and calcium-sensing receptor mutations in patients with FIHP. Whether FIHP is a variant or an early stage of MEN1 syndrome or hyperparathyroidism-jaw tumor syndrome is yet to be established. We present three siblings with familial isolated hyperparathyroidism due to solitary parathyroid adenoma and favorable evolution post-parathyroidectomy. Genetic tests revealed HRPT2 mutation.

Expression and characterization of androgen receptor coregulators, SRC-2 and HBO1, during human testis ontogenesis and in androgen signaling deficient patients.

Androgen receptor (AR) is essential for testicular physiology and spermatogenesis. SRC-2 and HBO1 are two AR coregulators yet their expression and roles in human testis are unknown. For the first time, we studied by immunohistochemistry and RT-PCR, the expression and distribution of these two coregulators during human testicular ontogenesis, in patients with altered AR signaling (Androgen insensitivity syndrome, AIS) and evaluated the functional impact of SRC-2 and HBO1 on AR signaling in a Sertoli cell context. SRC-2 was present in Sertoli cells at all developmental stages. HBO1 was barely or focally detected in the fetal testis yet its expression, in Sertoli and germ cells, drastically increased postnatally from early infancy to adulthood. In transient co-transfection studies we showed that SRC-2 induced, while HBO1 inhibited AR-mediated transactivation of reporter constructs in murine Sertoli SMAT1 cells. HBO1, but not SRC-2, expression was reduced in testes of patients with AIS compared to normal testes.

Evidence of an antifibrotic effect of immunosuppressive drugs: applications in the treatment of systemic sclerosis.

This review aims to present how a better understanding of the pathogenesis of tissue fibrosis and of the pivotal role of extracellular matrix components supports the use of various immunosuppressive drugs to treat systemic sclerosis (SSc). Recent experimental data demonstrating the antifibrotic effect of several immunosuppressive drugs, independently of their immunosuppressive action, must be put into context with the clinical results observed in immunosuppressed SSc patients. Ciclophosphamide is now considered the drug of choice for interstitial lung disease in SSc and in rapidly progressive diffuse SSc. Since 1996, this drug has been used at higher doses for autologous hematopoietic stem cell transplantations, permitting rapid and durable clinical and histological regression of skin fibrosis.