Performance of capsule endoscopy for the detection of small intestinal neuroendocrine tumors in familial carcinoid: a prospective single-site study.

BACKGROUND AND AIMS: Small-bowel neuroendocrine tumors (NETs) are slow growing, clinically silent tumors whose prognosis depends on disease stage. Members of kindreds with a familial form of small intestinal NETs (SI-NETs) represent a high-risk population for whom early detection improves disease outcome. Our aim was to determine the utility of small-bowel capsule endoscopy (SB-CE) for screening high-risk asymptomatic relatives from kindreds with familial carcinoid. METHODS: One hundred seventy-four asymptomatic subjects with a family history (≥2 family members) of SI-NETs were screened under Protocol NCT00646022, Natural History of Familial Carcinoid Tumor at the National Institutes of Health. All patients were imaged with SB-CE and 18fluoro-dihydroxphenylalanine (18F-DOPA) positron emission tomography (PET)/CT, and results were independently analyzed. Patients with a positive imaging study underwent surgical exploration. RESULTS: Thirty-five of 174 asymptomatic subjects screened for SI-NETs were positive on either SB-CE or 18F-DOPA PET. Thirty-two of 35 patients with a positive study were confirmed at surgery. SB-CE was positive in 28 of 32 patients with confirmed tumors for a per-patient sensitivity of 87.5%. SB-CE had a specificity of 97.3% and a negative predictive value of 96.5%. The average tumor number and size were 7.7 and 5.0 mm, respectively, and 81.2% of patients had multiple tumors. 18F-DOPA PET/CT had a similar sensitivity of 84% versus surgery. CONCLUSIONS: SB-CE is a sensitive and specific method comparable with 18F-DOPA PET/CT for screening high-risk patients with familial SI-NET. (Clinical trial registration number: NCT00646022.).

Diagnostic performance of [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the spine, and whole-body diagnostic CT and MRI in the detection of spinal bone metastases associated with pheochromocytoma and paraganglioma.

OBJECTIVE: To compare the diagnostic performance of [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the spine, and whole-body CT and MRI for the detection of pheochromocytoma/paraganglioma (PPGL)-related spinal bone metastases. MATERIALS AND METHODS: Between 2014 and 2020, PPGL participants with spinal bone metastases prospectively underwent [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the cervical-thoracolumbar spine (MRIspine), contrast-enhanced MRI of the neck and thoraco-abdominopelvic regions (MRIWB), and contrast-enhanced CT of the neck and thoraco-abdominopelvic regions (CTWB). Per-patient and per-lesion detection rates were calculated. Counting of spinal bone metastases was limited to a maximum of one lesion per vertebrae. A composite of all functional and anatomic imaging served as an imaging comparator. The McNemar test compared detection rates between the scans. Two-sided p values were reported. RESULTS: Forty-three consecutive participants (mean age, 41.7 ± 15.7 years; females, 22) with MRIspine were included who also underwent [68Ga]DOTATATE PET/CT (n = 43), [18F]FDG PET/CT (n = 43), MRIWB (n = 24), and CTWB (n = 33). Forty-one of 43 participants were positive for spinal bone metastases, with 382 lesions on the imaging comparator. [68Ga]DOTATATE PET/CT demonstrated a per-lesion detection rate of 377/382 (98.7%) which was superior compared to [18F]FDG (72.0%, 275/382, p < 0.001), MRIspine (80.6%, 308/382, p < 0.001), MRIWB (55.3%, 136/246, p < 0.001), and CTWB (44.8%, 132/295, p < 0.001). The per-patient detection rate of [68Ga]DOTATATE PET/CT was 41/41 (100%) which was higher compared to [18F]FDG PET/CT (90.2%, 37/41, p = 0.13), MRIspine (97.6%, 40/41, p = 1.00), MRIWB (95.7%, 22/23, p = 1.00), and CTWB (81.8%, 27/33, p = 0.03). CONCLUSIONS: [68Ga]DOTATATE PET/CT should be the modality of choice in PPGL-related spinal bone metastases due to its superior detection rate. CLINICAL RELEVANCE STATEMENT: In a prospective study of 43 pheochromocytoma/paraganglioma participants with spinal bone metastases, [68Ga]DOTATATE PET/CT had a superior per-lesion detection rate of 98.7% (377/382), compared to [18F]FDG PET/CT (p < 0.001), MRI of the spine (p < 0.001), whole-body CT (p < 0.001), and whole-body MRI (p < 0.001). KEY POINTS: • Data regarding head-to-head comparison between functional and anatomic imaging modalities to detect spinal bone metastases in pheochromocytoma/paraganglioma are limited. • [68Ga]DOTATATE PET/CT had a superior per-lesion detection rate of 98.7% in the detection of spinal bone metastases associated with pheochromocytoma/paraganglioma compared to other imaging modalities: [18]F-FDG PET/CT, MRI of the spine, whole-body CT, and whole-body MRI. • [68Ga]DOTATATE PET/CT should be the modality of choice in the evaluation of spinal bone metastases associated with pheochromocytoma/paraganglioma.

Sporadic Primary Pheochromocytoma: A Prospective Intraindividual Comparison of Six Imaging Tests (CT, MRI, and PET/CT Using 68Ga-DOTATATE, FDG, 18F-FDOPA, and 18F-FDA).

BACKGROUND. Recent professional society guidelines for radionuclide imaging of sporadic pheochromocytoma (PHEO) recommend 18F-fluorodihydroxyphenylala-nine (18F-FDOPA) as the radiotracer of choice, deeming 68Ga-DOTATATE and FDG to be second- and third-line agents, respectively. An additional agent, 18F-fluorodopamine (18F-FDA), remains experimental for PHEO detection. A paucity of research has performed head-to-head comparison among these agents. OBJECTIVE. The purpose of this study was to perform an intraindividual comparison of 68Ga-DOTATATE PET/CT, FDG PET/CT, 18F-FDOPA PET/CT, 18F-FDA PET/CT, CT, and MRI in visualization of sporadic primary PHEO. METHODS. This prospective study enrolled patients referred with clinical suspicion for sporadic PHEO. Patients were scheduled for 68Ga-DOTATATE PET/CT, FDG PET/CT, 18F-FDOPA PET/CT, 18F-FDA PET/CT, whole-body staging CT (portal venous phase), and MRI within a 3-month period. PET/CT examinations were reviewed by two nuclear medicine physicians, and CT and MRI were reviewed by two radiologists; differences were resolved by consensus. Readers scored lesions in terms of confidence in diagnosis of PHEO (1-5 scale; 4-5 considered positive for PHEO). Lesion-to-liver SUVmax was computed using both readers' measurements. Interreader agreement was assessed using intraclass correlation coefficients (ICCs) for SUVmax. Analysis included only patients with histologically confirmed PHEO on resection. RESULTS. The analysis included 14 patients (eight women, six men; mean age, 52.4 ± 16.8 [SD] years) with PHEO. Both 68Ga-DOTATATE PET/CT and FDG PET/CT were completed in all 14 patients, 18F-FDOPA PET/CT in 11, 18F-FDA PET/CT in 7, CT in 12, and MRI in 12. Mean conspicuity score for PHEO was 5.0 ± 0.0 for 18F-FDOPA PET/CT, 4.7 ± 0.5 for MRI, 4.6 ± 0.8 for 18F-FDA PET/CT, 4.4 ± 1.0 for 68Ga-DOTATATE PET/CT, 4.3 ± 1.0 for CT, and 4.1 ± 1.5 for FDG PET/CT. The positivity rate for PHEO was 100.0% (11/11) for 18F-FDOPA PET/CT, 100.0% (12/12) for MRI, 85.7% (6/7) for 18F-FDA PET/CT, 78.6% (11/14) for FDG PET/CT, 78.6% (11/14) for 68Ga-DOTATATE PET/CT, and 66.7% (8/12) for CT. Lesion-to-liver SUVmax was 10.5 for 18F-FDOPA versus 3.0-4.2 for the other tracers. Interreader agreement across modalities ranged from 85.7% to 100.0% for lesion positivity with ICCs of 0.55-1.00 for SUVmax measurements. CONCLUSION. Findings from this small intraindividual comparative study support 18F-FDOPA PET/CT as a preferred first-line imaging modality in evaluation of sporadic PHEO. CLINICAL IMPACT. This study provides data supporting current guidelines for imaging evaluation of suspected PHEO. TRIAL REGISTRATION. ClinicalTrials.gov NCT00004847.

End-of-treatment and serial PET imaging in primary mediastinal B-cell lymphoma following dose-adjusted EPOCH-R: a paradigm shift in clinical decision making.

Dose-adjusted-EPOCH-R obviates the need for radiotherapy in most patients with primary mediastinal B-cell lymphoma. End-of-treatment PET, however, does not accurately identify patients at risk of treatment failure, thereby confounding clinical decision making. To define the role of PET in primary mediastinal B-cell lymphoma following dose-adjusted-EPOCH-R, we extended enrollment and follow up on our published phase II trial and independent series. Ninety-three patients received dose-adjusted-EPOCH-R without radiotherapy. End-of-treatment PET was performed in 80 patients, of whom 57 received 144 serial scans. One nuclear medicine physician from each institution blindly reviewed all scans from their respective institution. End-of-treatment PET was negative (Deauville 1-3) in 55 (69%) patients with one treatment failure (8-year event-free and overall survival of 96.0% and 97.7%). Among 25 (31%) patients with a positive (Deauville 4-5) end-of-treatment PET, there were 5 (20%) treatment failures (8-year event-free and overall survival of 71.1% and 84.3%). Linear regression analysis of serial scans showed a significant decrease in SUVmax in positive end-of-treatment PET non-progressors compared to an increase in treatment failures. Among 6 treatment failures, the median end-of-treatment SUVmax was 15.4 (range, 1.9-21.3), and 4 achieved long-term remission with salvage therapy. Virtually all patients with a negative end-of-treatment PET following dose-adjusted-EPOCH-R achieved durable remissions and should not receive radiotherapy. Among patients with a positive end-of-treatment PET, only 5/25 (20%) had treatment-failure. Serial PET imaging distinguished end-of-treatment PET positive patients without treatment failure, thereby reducing unnecessary radiotherapy by 80%, and should be considered in all patients with an initial positive PET following dose-adjusted-EPOCH-R (clinicaltrials.gov identifier 00001337).

Dose-adjusted EPOCH-rituximab therapy in primary mediastinal B-cell lymphoma.

BACKGROUND: Primary mediastinal B-cell lymphoma is a distinct subtype of diffuse large-B-cell lymphoma that is closely related to nodular sclerosing Hodgkin's lymphoma. Patients are usually young and present with large mediastinal masses. There is no standard treatment, but the inadequacy of immunochemotherapy alone has resulted in routine consolidation with mediastinal radiotherapy, which has potentially serious late effects. We aimed to develop a strategy that improves the rate of cure and obviates the need for radiotherapy. METHODS: We conducted a single-group, phase 2, prospective study of infusional dose-adjusted etoposide, doxorubicin, and cyclophosphamide with vincristine, prednisone, and rituximab (DA-EPOCH-R) and filgrastim without radiotherapy in 51 patients with untreated primary mediastinal B-cell lymphoma. We used results from a retrospective study of DA-EPOCH-R from another center to independently verify the outcomes. RESULTS: The patients had a median age of 30 years (range, 19 to 52) and a median tumor diameter of 11 cm; 59% were women. During a median of 5 years of follow-up, the event-free survival rate was 93%, and the overall survival rate was 97%. Among the 16 patients who were involved in the retrospective analysis at another center, over a median of 3 years of follow-up, the event-free survival rate was 100%, and no patients received radiotherapy. No late morbidity or cardiac toxic effects were found in any patients. After follow-up ranging from 10 months to 14 years, all but 2 of the 51 patients (4%) who received DA-EPOCH-R alone were in complete remission. The 2 remaining patients received radiotherapy and were disease-free at follow-up. CONCLUSIONS: Therapy with DA-EPOCH-R obviated the need for radiotherapy in patients with primary mediastinal B-cell lymphoma. (Funded by the National Cancer Institute; ClinicalTrials.gov number, NCT00001337.).

A Hereditary Form of Small Intestinal Carcinoid Associated With a Germline Mutation in Inositol Polyphosphate Multikinase.

BACKGROUND & AIMS: Small intestinal carcinoids are rare and difficult to diagnose and patients often present with advanced incurable disease. Although the disease occurs sporadically, there have been reports of family clusters. Hereditary small intestinal carcinoid has not been recognized and genetic factors have not been identified. We performed a genetic analysis of families with small intestinal carcinoids to establish a hereditary basis and find genes that might cause this cancer. METHODS: We performed a prospective study of 33 families with at least 2 cases of small intestinal carcinoids. Affected members were characterized clinically and asymptomatic relatives were screened and underwent exploratory laparotomy for suspected tumors. Disease-associated mutations were sought using linkage analysis, whole-exome sequencing, and copy number analyses of germline and tumor DNA collected from members of a single large family. We assessed expression of mutant protein, protein activity, and regulation of apoptosis and senescence in lymphoblasts derived from the cases. RESULTS: Familial and sporadic carcinoids are clinically indistinguishable except for the multiple synchronous primary tumors observed in most familial cases. Nearly 34% of asymptomatic relatives older than age 50 were found to have occult tumors; the tumors were cleared surgically from 87% of these individuals (20 of 23). Linkage analysis and whole-exome sequencing identified a germline 4-bp deletion in the gene inositol polyphosphate multikinase (IPMK), which truncates the protein. This mutation was detected in all 11 individuals with small intestinal carcinoids and in 17 of 35 family members whose carcinoid status was unknown. Mutant IPMK had reduced kinase activity and nuclear localization, compared with the full-length protein. This reduced activation of p53 and increased cell survival. CONCLUSIONS: We found that small intestinal carcinoids can occur as an inherited autosomal-dominant disease. The familial form is characterized by multiple synchronous primary tumors, which might account for 22%-35% of cases previously considered sporadic. Relatives of patients with familial carcinoids should be screened to detect curable early stage disease. IPMK haploinsufficiency promotes carcinoid tumorigenesis.

PET/CT comparing (68)Ga-DOTATATE and other radiopharmaceuticals and in comparison with CT/MRI for the localization of sporadic metastatic pheochromocytoma and paraganglioma.

PURPOSE: Pheochromocytomas/paragangliomas (PPGLs) and their metastases are tumors that predominantly express somatostatin receptor 2 (SSR2). (68)Ga-DOTA(0)-Tyr(3)-octreotate ((68)Ga-DOTATATE) is a PET radiopharmaceutical with both high and selective affinity for SSRs. The purpose of this study was to evaluate the utility of (68)Ga-DOTATATE in comparison with other specific and nonspecific radiopharmaceuticals recommended in the current guidelines for the localization of metastatic sporadic PPGL by PET/CT. METHODS: This prospective study included 22 patients (15 men, 7 women; aged 50.0 ± 13.9 years) with confirmed metastatic PPGL, a negative family history for PPGL, and negative genetic testing, who underwent (68)Ga-DOTATATE, (18)F-fluoro-2-deoxy-D-glucose ((18)F-FDG) PET/CT, and CT/MRI. Only 12 patients underwent an additional (18)F-fluorodihydroxyphenylalanine ((18)F-FDOPA) PET/CT scan and only 11 patients underwent an additional (18)F-fluorodopamine ((18)F-FDA) PET/CT scan. The rates of detection of metastatic lesions were compared among all the imaging studies. A composite of all functional and anatomical imaging studies served as the imaging comparator. RESULTS: (68)Ga-DOTATATE PET/CT showed a lesion-based detection rate of 97.6 % (95 % confidence interval, CI, 95.8 - 98.7 %). (18)F-FDG PET/CT, (18)F-FDOPA PET/CT, (18)F-FDA PET/CT, and CT/MRI showed detection rates of 49.2 % (CI 44.5 - 53.6 %; p < 0.01), 74.8 % (CI 69.0 - 79.9 %); p < 0.01), 77.7 % (CI 71.5 - 82.8 %; p < 0.01), and 81.6 % (CI 77.8 - 84.8 %; p < 0.01), respectively. CONCLUSION: The results of this study demonstrate the superiority of (68)Ga-DOTATATE PET/CT in the localization of sporadic metastatic PPGLs compared to all other functional and anatomical imaging modalities, and suggest modification of future guidelines towards this new imaging modality.

CHARACTERISTICS AND OUTCOMES OF METASTATIC SDHB AND SPORADIC PHEOCHROMOCYTOMA/PARAGANGLIOMA: AN NATIONAL INSTITUTES OF HEALTH STUDY.

OBJECTIVE: Overall about 10 to 20% of pheochromocytomas/paragangliomas (PHEOs/PGLs) are metastatic, with higher metastatic potential observed in succinate dehydrogenase subunit B/fumarate hydratase (SDHB/FH)-related tumors. Due to the improved availability of biochemical and genetic testing and the frequent use of anatomical/functional imaging, there is currently a higher detection rate of metastatic PHEO/PGL. METHODS: A retrospective analysis of 132 patients (27 children, 105 adults) with metastatic PHEO/PGL diagnosed and treated from 2000 to 2014 was conducted. RESULTS: Seventy-seven (58%) males and 55 (42%) females were included; 39 (30%) have died, with no sex preference. Seventy-three (55%) patients had SDHB mutations; 59 (45%) patients had apparently sporadic tumors (AST). SDHB patients had an average age at primary tumor diagnosis of 31 ± 16 years compared to 40 ± 15 years in AST patients (P<.001). The average metastatic interval (MI) decreased with increasing age in both SDHB and AST patients (P = .013 for both). Only 16% of all primary tumors were smaller than 4.5 cm. Eleven percent of patients had biochemically silent disease, more with SDHB. Of SDHB patients, 23% had metastatic tumors at first diagnosis, compared to 15% of AST patients. Five- and 10-year survival rates were significantly better for metastatic AST than SDHB patients (P = .01). Overall survival was significantly different between children and adults (P = .037); this was mostly attributed to the SDHB patients, in whom children had statistically significantly longer survival than adults (P = .006). The deceased patients all died due to the PHEO/PGL and mainly had noradrenergic phenotypes. CONCLUSION: In children, metastatic PHEOs/PGLs are mainly due to SDHB mutations; in adults they are equally distributed between in SDHB mutations and AST, with better 5- and 10-year survival rates for ASTs. In SDHB patients, children survive longer than adults. Primary metastatic tumors, most presenting as noradrenergic PGLs, are larger than 4.5 cm in >80% of patients. The frequency of metastatic tumors from primary AST increases with age, including a decreased MI compared to SDHB tumors. These results support several recommendations that are summarized in the Discussion.

Circulating tumour DNA and CT monitoring in patients with untreated diffuse large B-cell lymphoma: a correlative biomarker study.

BACKGROUND: Diffuse large-B-cell lymphoma is curable, but when treatment fails, outcome is poor. Although imaging can help to identify patients at risk of treatment failure, they are often imprecise, and radiation exposure is a potential health risk. We aimed to assess whether circulating tumour DNA encoding the clonal immunoglobulin gene sequence could be detected in the serum of patients with diffuse large-B-cell lymphoma and used to predict clinical disease recurrence after frontline treatment. METHODS: We used next-generation DNA sequencing to retrospectively analyse cell-free circulating tumour DNA in patients assigned to one of three treatment protocols between May 8, 1993, and June 6, 2013. Eligible patients had diffuse large-B-cell lymphoma, no evidence of indolent lymphoma, and were previously untreated. We obtained serial serum samples and concurrent CT scans at specified times during most treatment cycles and up to 5 years of follow-up. VDJ gene segments of the rearranged immunoglobulin receptor genes were amplified and sequenced from pretreatment specimens and serum circulating tumour DNA encoding the VDJ rearrangements was quantitated. FINDINGS: Tumour clonotypes were identified in pretreatment specimens from 126 patients who were followed up for a median of 11 years (IQR 6·8-14·2). Interim monitoring of circulating tumour DNA at the end of two treatment cycles in 108 patients showed a 5-year time to progression of 41·7% (95% CI 22·2-60·1) in patients with detectable circulating tumour DNA and 80·2% (69·6-87·3) in those without detectable circulating tumour DNA (p<0·0001). Detectable interim circulating tumour DNA had a positive predictive value of 62·5% (95% CI 40·6-81·2) and a negative predictive value of 79·8% (69·6-87·8). Surveillance monitoring of circulating tumour DNA was done in 107 patients who achieved complete remission. A Cox proportional hazards model showed that the hazard ratio for clinical disease progression was 228 (95% CI 51-1022) for patients who developed detectable circulating tumour DNA during surveillance compared with patients with undetectable circulating tumour DNA (p<0·0001). Surveillance circulating tumour DNA had a positive predictive value of 88·2% (95% CI 63·6-98·5) and a negative predictive value of 97·8% (92·2-99·7) and identified risk of recurrence at a median of 3·5 months (range 0-200) before evidence of clinical disease. INTERPRETATION: Surveillance circulating tumour DNA identifies patients at risk of recurrence before clinical evidence of disease in most patients and results in a reduced disease burden at relapse. Interim circulating tumour DNA is a promising biomarker to identify patients at high risk of treatment failure. FUNDING: National Cancer Institute and Adaptive Biotechnologies.

Translational predictive biomarker analysis of the phase 1b sorafenib and bevacizumab study expansion cohort.

Predictive biomarkers are needed to triage patients to the best therapy. We prospectively planned examination of sequential blood, biopsy, and functional imaging with which to confirm the mechanism and to identify potential predictive biomarkers in a phase Ib clinical trial expansion of patients with solid tumors receiving sorafenib/bevacizumab. The maximally tolerated doses of sorafenib at 200 mg twice daily with bevacizumab at 5 mg/kg every other week were given to biopsiable patients. Patients were randomized to receive either sorafenib or bevacizumab monotherapy for the first 28-day cycle with the second drug added with cycle 2. Biopsies, dynamic contrast-enhanced MRI, and fluorodeoxyglucose-proton emission tomography were done pre-therapy and at 2 and 6 weeks (2 weeks into combination therapy). Tumor and serum proteomics, Ras/Raf mutational analysis, and functional imaging results were examined individually and across the dataset to identify potential changes predictive of response to therapy and those that confirm the biochemical drug mechanism(s). Therapy with sorafenib/bevacizumab resulted in clinical benefit in 45% of this mixed solid tumor group. ERK activation and microvessel density were decreased with monotherapy treatment with sorafenib or bevacizumab, respectively; whereas a decreased signal over the group of total AKT, phospho(p)-VEGF receptor2, p-endothelial nitric-oxide synthase, b-RAF, and cleaved poly(ADP-ribose) polymerase was associated with earlier progression of disease. Tumor metabolic activity decreased in those patients with clinical benefits lasting longer than 4 months, and activity increased with progression of disease. Cleavage of caspase 3 and poly(ADP-ribose) polymerase was increased, and Ki67 expression decreased in patients with prolonged clinical benefits, consistent with decreased proliferation and increased apoptosis. The conglomerate analysis, incorporating pharmacodynamic and tumor biochemistry, demonstrated sorafenib/bevacizumab-targeted vascular activity in the tumor. Results suggest potential biomarkers for which changes, as a group, during early therapeutic exposure may predict clinical benefit.

Early responses to adenoviral-mediated transfer of the aquaporin-1 cDNA for radiation-induced salivary hypofunction.

No conventional therapy exists for salivary hypofunction in surviving head and neck cancer patients with Radiation Therapy Oncology Group late grade 2-3 toxicity. We conducted a phase I clinical trial to test the safety and biologic efficacy of serotype 5, adenoviral-mediated aquaporin-1 cDNA transfer to a single previously irradiated parotid gland in 11 subjects using an open label, single-dose, dose-escalation design (AdhAQP1 vector; four dose tiers from 4.8 × 10(7) to 5.8 × 10(9) vector particles per gland). Treated subjects were followed at scheduled intervals. Multiple safety parameters were measured and biologic efficacy was evaluated with measurements of parotid salivary flow rate. Symptoms were assessed with a visual analog scale. All subjects tolerated vector delivery and study procedures well over the 42-d study period reported. No deaths, serious adverse events, or dose-limiting toxicities occurred. Generally, few adverse events occurred, and all were considered mild or moderate. No consistent changes were found in any clinical chemistry and hematology parameters measured. Objective responses were seen in six subjects, all at doses <5.8 × 10(9) vector particles per gland. Five of these six subjects also experienced subjective improvement in xerostomia. AdhAQP1 vector delivery to a single parotid gland was safe and transfer of the hAQP1 cDNA increased parotid flow and relieved symptoms in a subset of subjects.

Diagnosis and preoperative imaging of multiple endocrine neoplasia type 2: current status and future directions.

Multiple endocrine neoplasia type 2 (MEN2) is a rare autosomal dominant syndrome caused by mutations in the RET protooncogene and is characterized by a strong penetrance of medullary thyroid carcinoma (all subtypes) and is often accompanied by pheochromocytoma (MEN2A/2B) and primary hyperparathyroidism (MEN2A). The evaluation and management of MEN2-related tumours is often different from that of sporadic counterparts. This review article provides an overview of clinical manifestations, diagnosis and surgical management of MEN2 patients. This review also presents applications of the most up-to-date imaging modalities to MEN2 patients that are tightly linked to the clinical management and aims to guide physicians towards a rationale for the use of imaging prior to prophylactic thyroidectomy, initial surgery and reoperations for persistent/recurrent disease. This review also concludes that, in the near future, it is expected that these patients will indeed benefit from newly developed positron emission tomography approaches which will target peptide receptors and protein kinases. Identification of MEN2-specific radiopharmaceuticals will also soon arise from molecular profiling studies. Furthermore, subtotal (cortical-sparing) adrenalectomy, which is a valid option in MEN2 for avoiding long-term steroid replacement, will benefit from an accurate estimation through imaging of differential adrenocortical function.

18F-FDG PET/CT as a predictor of hereditary head and neck paragangliomas.

BACKGROUND: Hereditary head and neck paragangliomas (HNPGLs) account for at least 35% of all HNPGLs, most commonly due to germline mutations in SDHx susceptibility genes. Several studies about sympathetic paragangliomas have shown that (18)F-FDG PET/CT was not only able to detect and localize tumours, but also to characterize tumours ((18)F-FDG uptake being linked to SDHx mutations). However, the data concerning (18)F-FDG uptake specifically in HNPGLs have not been addressed. The aim of this study was to evaluate the relationship between (18)F-FDG uptake and the SDHx mutation status in HNPGL patients. METHODS: (18)F-FDG PET/CT from sixty HNPGL patients were evaluated. For all lesions, we measured the maximum standardized uptake values (SUVmax), and the uptake ratio defined as HNPGL-SUVmax over pulmonary artery trunk SUVmean (SUVratio). Tumour sizes were assessed on radiological studies. RESULTS: Sixty patients (53.3% with SDHx mutations) were evaluated for a total of 106 HNPGLs. HNPGLs-SUVmax and SUVratio were highly dispersed (1.2-30.5 and 1.0-17.0, respectively). The HNPGL (18)F-FDG uptake was significantly higher in SDHx versus sporadic tumours on both univariate and multivariate analysis (P = 0.002). We developed two models for calculating the probability of a germline SDHx mutation. The first one, based on a per-lesion analysis, had an accuracy of 75.5%. The second model, based on a per-patient analysis, had an accuracy of 80.0%. CONCLUSIONS: (18)F-FDG uptake in HNPGL is strongly dependent on patient genotype. Thus, the degree of (18)F-FDG uptake in these tumours can be used clinically to help identify patients in whom SDHx mutations should be suspected.

Adrenal nodular hyperplasia in hereditary leiomyomatosis and renal cell cancer.

PURPOSE: The condition hereditary leiomyomatosis and renal cell carcinoma is characterized by cutaneous leiomyomas, uterine fibroids and aggressive papillary renal cell carcinoma. A number of our patients with hereditary leiomyomatosis and renal cell carcinoma had atypical adrenal nodules, which were further evaluated to determine whether these nodules were associated with hereditary leiomyomatosis and renal cell carcinoma. MATERIALS AND METHODS: Patients with hereditary leiomyomatosis and renal cell carcinoma underwent a comprehensive clinical and genetic evaluation. We reviewed the clinical presentation, anatomical and functional imaging, endocrine evaluation, pathological examination and germline mutation testing results. RESULTS: Of 255 patients with hereditary leiomyomatosis and renal cell carcinoma 20 (7.8%) had primary adrenal lesions, including 4 with bilateral adrenal lesions and 4 with multiple nodules. Two patients had adrenocorticotropic hormone independent hypercortisolism. A total of 27 adrenal lesions were evaluated. The imaging characteristics of 5 of these lesions (18.5%) were not consistent with adenoma by noncontrast computerized tomography criteria. Positron emission tomography was positive in 7 of 10 cases (70%). A total of 12 nodules were surgically resected from 10 adrenal glands. Pathological examination revealed macronodular adrenal hyperplasia in all specimens. CONCLUSIONS: Unilateral and bilateral adrenal nodular hyperplasia was detected in a subset of patients with hereditary leiomyomatosis and renal cell carcinoma. A functional endocrine evaluation is recommended when an adrenal lesion is discovered. Imaging frequently reveals lesions that are not typical of adenomas and positron emission tomography may be positive. To date no patient has had adrenal malignancy, and active surveillance of hereditary leiomyomatosis and renal cell carcinoma adrenal nodules appears justified.

Functional characterization of nonmetastatic paraganglioma and pheochromocytoma by (18) F-FDOPA PET: focus on missed lesions.

AIMS AND METHODS: To evaluate the clinical value of (18) F-fluorodihydroxyphenylalanine ((18) F-FDOPA) PET in relation to tumour localization and the patient's genetic status in a large series of pheochromocytoma/paraganglioma (PHEO/PGL) patients and to discuss in detail false-negative results. A retrospective study of PGL patients who were investigated with (18) F-FDOPA PET or PET/CT imaging in two academic endocrine tumour centres was conducted (La Timone University Hospital, Marseilles, France and National Institutes of Health (NIH), Bethesda, MD, USA). RESULTS: One hundred sixteen patients (39·7% harbouring germline mutations in known disease susceptibility genes) were evaluated for a total of 195 PHEO/PGL foci. (18) F-FDOPA PET correctly detected 179 lesions (91·8%) in 107 patients (92·2%). Lesion-based sensitivities for parasympathetic PGLs (head, neck, or anterior/middle thoracic ones), PHEOs, and extra-adrenal sympathetic (abdominal or posterior thoracic) PGLs were 98·2% [96·5% for Timone and 100% for NIH], 93·9% [93·8 and 93·9%] and 70·3% [47·1 and 90%] respectively (P < 0·001). Sympathetic (adrenal and extra-adrenal) SDHx-related PGLs were at a higher risk for negative (18) F-FDOPA PET than non-SDHx-related PGLs (14/24 vs 0/62, respectively, P < 0·001). In contrast, the risk of negative (18) F-FDOPA PET was lower for parasympathetic PGLs regardless of the genetic background (1/90 in SDHx vs 1/19 in non-SDHx tumours, P = 0·32). (18) F-FDOPA PET failed to detect two head and neck PGLs (HNPGL), likely due to their small size, whereas most missed sympathetic PGL were larger and may have exhibited a specific (18) F-FDOPA-negative imaging phenotype. (18) F-FDG PET detected all the missed sympathetic lesions. CONCLUSIONS: (18) F-FDOPA PET appears to be a very sensitive functional imaging tool for HNPGL regardless of the genetic status of the tumours. Patients with false-negative tumours on (18) F-FDOPA PET should be tested for SDHx mutations.

A pharmacodynamic study of the P-glycoprotein antagonist CBT-1® in combination with paclitaxel in solid tumors.

BACKGROUND: This pharmacodynamic trial evaluated the effect of CBT-1® on efflux by the ATP binding cassette (ABC) multidrug transporter P-glycoprotein (Pgp/MDR1/ABCB1) in normal human cells and tissues. CBT-1® is an orally administered bisbenzylisoquinoline Pgp inhibitor being evaluated clinically. Laboratory studies showed potent and durable inhibition of Pgp, and in phase I studies CBT-1® did not alter the pharmacokinetics of paclitaxel or doxorubicin. METHODS: CBT-1® was dosed at 500 mg/m2 for 7 days; a 3-hour infusion of paclitaxel at 135 mg/m2 was administered on day 6. Peripheral blood mononuclear cells (PBMCs) were obtained prior to CBT-1® administration and on day 6 prior to the paclitaxel infusion. (99m)Tc-sestamibi imaging was performed on the same schedule. The area under the concentration-time curve from 0-3 hours (AUC(0-3)) was determined for (99m)Tc-sestamibi. RESULTS: Twelve patients were planned and enrolled. Toxicities were minimal and related to paclitaxel (grade 3 or 4 neutropenia in 18% of cycles). Rhodamine efflux from CD56+ PBMCs was a statistically significant 51%-100% lower (p < .0001) with CBT-1®. Among 10 patients who completed imaging, the (99m)Tc-sestamibi AUC(0-3) for liver (normalized to the AUC(0-3) of the heart) increased from 34.7% to 100.8% (median, 71.9%; p < .0001) after CBT-1® administration. Lung uptake was not changed. CONCLUSION: CBT-1® is able to inhibit Pgp-mediated efflux from PBMCs and normal liver to a degree observed with Pgp inhibitors studied in earlier clinical trials. Combined with its ease of administration and lack of toxicity, the data showing inhibition of normal tissue Pgp support further studies with CBT-1® to evaluate its ability to modulate drug uptake in tumor tissue. DISCUSSION: Although overexpression of ABCB1 and other ABC transporters has been linked with poor outcome following chemotherapy efforts to negate that through pharmacologic inhibition have generally failed. This is thought to be a result of several factors, including (a) failure to select patients with tumors in which ABCB1 is a dominant resistance mechanism; (b) inhibitors that were not potent, or that impaired drug clearance; and (c) the existence of other mechanisms of drug resistance, including other ABC transporters. Although an animal model for Pgp has been lacking, recent studies have exploited a Brca1(-/-); p53(-/-) mouse model of hereditary breast cancer that develops sporadic tumors similar to cancers in women harboring BRCA1 mutations. Treatment with doxorubicin, docetaxel, or the poly(ADP-ribose) polymerase inhibitor olaparib brings about shrinkage, but resistance eventually emerges. Overexpression of the Abcb1a gene, the mouse ortholog of human ABCB1, has been shown to be a mechanism of resistance in a subset of these tumors. Treating mice with resistant tumors with olaparib plus the Pgp inhibitor tariquidar resensitized the tumors to olaparib. Although results in this animal model support a new look at Pgp as a target, in this era of "targeted therapies," trial designs that directly assess modulation of drug uptake, including quantitative nuclear imaging, should be pursued before clinical efficacy assessments are undertaken. Such assessment should be performed with compounds that inhibit tissue Pgp without altering the pharmacokinetics of chemotherapeutic agents. This pharmacodynamic study demonstrated that CBT-1®, inhibits Pgp-mediated efflux from PBMCs and normal liver.

Molecular imaging of adrenal neoplasms.

The adrenal glands are complex structures from which a variety of benign and malignant tumors may arise and are a common site of metastatic disease. Several radiopharmaceuticals are used for imaging the adrenals, including I-123/I-131 metaiodobenzylguanidine (MIBG), norcholesterol derivatives, In-111 pentetreotide and Ga-68 somatostatin analogs, [F-18]fluorodeoxyglucose, [F-18]fluorodopa, [F-18]fluorodopamine, C-11 meta hydroxyephedrine, and C-11/F-18/I-123 Metomidate (MTO) or its analogs. In this review we focus on the role of these reagents in metastatic lesions, cortical neoplasms, pheochromocytoma/paraganglioma, and neuroblastoma (NB).

Radionuclide therapy of adrenal tumors.

Adrenal tumors arising from chromaffin cells will often accumulate radiolabeled metaiodobenzylguanidine (MIBG) and thus are amenable to therapy with I-131 MIBG. More recently, therapy studies have targeted the somatostatin receptors using Lu-177 or Y-90 radiolabeled somatostatin analogs. Because pheochromocytoma (PHEO)/paraganglioma (PGL) and neuroblastoma (NB), which often arise from the adrenals, express these receptors, clinical trials have been performed with these reagents. We will review the experience using radionuclide therapy for targeting PHEO/PGL and NBs.

Performances of Functional and Anatomic Imaging Modalities in Succinate Dehydrogenase A-Related Metastatic Pheochromocytoma and Paraganglioma.

The study identifies the importance of positron emission tomographic (PET) and anatomic imaging modalities and their individual performances in detecting succinate dehydrogenase A (SDHA)-related metastatic pheochromocytoma and paraganglioma (PPGL). The detection rates of PET modalities-68Ga-DOTATATE, 18F-FDG, and 18F-FDOPA-along with the combination of computed tomography (CT) and magnetic resonance imaging (MRI) are compared in a cohort of 11 patients with metastatic PPGL in the setting of a germline SDHA mutation. The imaging detection performances were evaluated at three levels: overall lesions, anatomic regions, and a patient-by-patient basis. 68Ga-DOTATATE PET demonstrated a lesion-based detection rate of 88.6% [95% confidence interval (CI), 84.3-92.5%], while 18F-FDG, 18F-FDOPA, and CT/MRI showed detection rates of 82.9% (CI, 78.0-87.1%), 39.8% (CI, 30.2-50.2%), and 58.2% (CI, 52.0-64.1%), respectively. The study found that 68Ga-DOTATATE best detects lesions in a subset of patients with SDHA-related metastatic PPGL. However, 18F-FDG did detect more lesions in the liver, mediastinum, and abdomen/pelvis anatomic regions, showing the importance of a combined approach using both PET modalities in evaluating SDHA-related PPGL.

Parathyroid Imaging: Past, Present, and Future.

The goal of parathyroid imaging is to identify all sources of excess parathyroid hormone secretion pre-operatively. A variety of imaging approaches have been evaluated and utilized over the years for this purpose. Ultrasound relies solely on structural features and is without radiation, however is limited to superficial evaluation. 4DCT and 4DMRI provide enhancement characteristics in addition to structural features and dynamic enhancement has been investigated as a way to better distinguish parathyroid from adjacent structures. It is important to recognize that 4DCT provides valuable information however results in much higher radiation dose to the thyroid gland than the other available examinations, and therefore the optimal number of phases is an area of controversy. Single-photon scintigraphy with 99mTc-Sestamibi, or dual tracer 99mTc-pertechnetate and 99mTc-sestamibi with or without SPECT or SPECT/CT is part of the standard of care in many centers with availability and expertise in nuclear medicine. This molecular imaging approach detects cellular physiology such as mitochondria content found in parathyroid adenomas. Combining structural imaging such as CT or MRI with molecular imaging in a hybrid approach allows the ability to obtain robust structural and functional information in one examination. Hybrid PET/CT is widely available and provides improved imaging and quantification over SPECT or SPECT/CT. Emerging PET imaging techniques, such as 18F-Fluorocholine, have the exciting potential to reinvent parathyroid imaging. PET/MRI may be particularly well suited to parathyroid imaging, where available, because of the ability to perform dynamic contrast-enhanced imaging and co-registered 18F-Fluorocholine PET imaging simultaneously with low radiation dose to the thyroid. A targeted agent specific for a parathyroid tissue biomarker remains to be identified.