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K Nazar A, Basu S. Radiolabeled Somatostatin Analogs for Cancer Imaging. Semin Nucl Med 2024:S0001-2998(24)00058-8. [PMID: 39122608 DOI: 10.1053/j.semnuclmed.2024.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2024] [Accepted: 07/01/2024] [Indexed: 08/12/2024]
Abstract
Somatostatin receptors (SSTR) are expressed by many tumours especially those related to neuro-endocrine origin and molecular functional imaging of SSTR expression using radiolabelled somatostatin analogs have revolutionized imaging of patients with these group of malignancies. Coming a long way from the first radiolabelled somatostatin analog 123I-Tyr-3-octreotide, there has been significant developments in terms of radionuclides used, the ligands and somatostatin derivatives. 111In-Pentetreotide extensively employed for imaging NETs at the beginning has now been replaced by 68Ga-SSA based PET-CT. SSA-PET/CT performs superior to conventional imaging modalities and has evolved in the mainframe for NET imaging. The advantages were multiple: (i) superior spatial resolution of PET versus SPECT, (ii) quantitative capabilities of PET aiding in disease activity and treatment response monitoring with better precision, (iii) shorter scan time and (iv) less patient exposure to radiation. The modality is indicated for staging, detecting the primary in CUP-NETs, restaging, treatment planning (along with FDG: the concept of dual-tracer PET-CT) as well as treatment response evaluation and follow-up of NETs. SSA PET/CT has also been incorporated in the guidelines for imaging of Pheochromocytoma-Paraganglioma, Medullary carcinoma thyroid, Meningioma and Tumor induced osteomalacia. At present, there is rising interest on (a) 18F-labelled SSA, (b) 64Cu-labelled SSA, and (c) somatostatin antagonists. 18F offers excellent imaging properties, 64Cu makes delayed imaging feasible which has implications in dosimetry and SSTR antagonists bind with the SST receptors with high affinity and specificity, providing high contrast images with less background, which can be translated to theranostics effectively. SSTR have been demonstrated in non-neuroendocrine tumours as well in the peer-reviewed literature, with studies demonstrating the potential of SSA PET/CT in Neuroblastoma, Nasopharyngeal carcinoma, carcinoma prostate (neuroendocrine differentiation) and lymphoma. This review will focus on the currently available SSAs and their history, different SPECT/PET agents, SSTR antagonists, comparison between the various imaging tracers, and their utility in both neuroendocrine and non-neuroendocrine tumors.
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Affiliation(s)
- Aamir K Nazar
- Radiation Medicine Centre, Bhabha Atomic Research Centre, Tata Memorial Centre Annexe, Mumbai; Homi Bhabha National Institute, Mumbai
| | - Sandip Basu
- Radiation Medicine Centre, Bhabha Atomic Research Centre, Tata Memorial Centre Annexe, Mumbai; Homi Bhabha National Institute, Mumbai.
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Pedersen EA, Verhaegen ME, Joseph MK, Harms KL, Harms PW. Merkel cell carcinoma: updates in tumor biology, emerging therapies, and preclinical models. Front Oncol 2024; 14:1413793. [PMID: 39136002 PMCID: PMC11317257 DOI: 10.3389/fonc.2024.1413793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Accepted: 07/08/2024] [Indexed: 08/15/2024] Open
Abstract
Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine carcinoma thought to arise via either viral (Merkel cell polyomavirus) or ultraviolet-associated pathways. Surgery and radiotherapy have historically been mainstays of management, and immunotherapy has improved outcomes for advanced disease. However, there remains a lack of effective therapy for those patients who fail to respond to these established approaches, underscoring a critical need to better understand MCC biology for more effective prognosis and treatment. Here, we review the fundamental aspects of MCC biology and the recent advances which have had profound impact on management. The first genetically-engineered mouse models for MCC tumorigenesis provide opportunities to understand the potential MCC cell of origin and may prove useful for preclinical investigation of novel therapeutics. The MCC cell of origin debate has also been advanced by recent observations of MCC arising in association with a clonally related hair follicle tumor or squamous cell carcinoma in situ. These studies also suggested a role for epigenetics in the origin of MCC, highlighting a potential utility for this therapeutic avenue in MCC. These and other therapeutic targets form the basis for a wealth of ongoing clinical trials to improve MCC management. Here, we review these recent advances in the context of the existing literature and implications for future investigations.
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Affiliation(s)
| | | | - Mallory K. Joseph
- Department of Dermatology, University of Michigan, Ann Arbor, MI, United States
| | - Kelly L. Harms
- Department of Dermatology, University of Michigan, Ann Arbor, MI, United States
| | - Paul W. Harms
- Department of Dermatology, University of Michigan, Ann Arbor, MI, United States
- Department of Pathology, University of Michigan, Ann Arbor, MI, United States
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Song H, Sgouros G. Alpha and Beta Radiation for Theragnostics. PET Clin 2024; 19:307-323. [PMID: 38688775 DOI: 10.1016/j.cpet.2024.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Targeted radionuclide therapy (TRT) has significantly evolved from its beginnings with iodine-131 to employing carrier molecules with beta emitting isotopes like lutetium-177. With the success of Lu-177-DOTATATE for neuroendocrine tumors and Lu-177-PSMA-617 for prostate cancer, several other beta emitting radioisotopes, such as Cu-67 and Tb-161, are being explored for TRT. The field has also expanded into targeted alpha therapy (TAT) with agents like radium-223 for bone metastases in prostate cancer, and several other alpha emitter radioisotopes with carrier molecules, such as Ac-225, and Pb-212 under clinical trials. Despite these advancements, the scope of TRT in treating diverse solid tumors and integration with other therapies like immunotherapy remains under investigation. The success of antibody-drug conjugates further complements treatments with TRT, though challenges in treatment optimization continue.
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Affiliation(s)
- Hong Song
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Stanford University, Stanford, CA 94305, USA.
| | - George Sgouros
- Division of Radiological Physics, Department of Radiology and Radiological Sciences, The Johns Hopkins University, Baltimore, MD 21205, USA
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Kircher M, Amerein A, Augustin M, Reitsam NG, Enke JS, Patt M, Wienand G, Bundschuh RA, Pfob CH, Lapa C, Dierks A. SSTR Antagonists as Theranostic Option in Merkel Cell Carcinoma. J Nucl Med 2024; 65:jnumed.123.267124. [PMID: 38331456 PMCID: PMC11149596 DOI: 10.2967/jnumed.123.267124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 01/11/2024] [Indexed: 02/10/2024] Open
Affiliation(s)
- Malte Kircher
- Department of Nuclear Medicine, Faculty of Medicine, University of Augsburg, Augsburg, Germany;
| | - Adriana Amerein
- Department of Nuclear Medicine, Faculty of Medicine, University of Augsburg, Augsburg, Germany
| | - Mareike Augustin
- Department of Dermatology, Faculty of Medicine, University of Augsburg, Augsburg, Germany; and
| | - Nic G Reitsam
- Department of Pathology, Faculty of Medicine, University of Augsburg, Augsburg, Germany
| | - Johanna S Enke
- Department of Nuclear Medicine, Faculty of Medicine, University of Augsburg, Augsburg, Germany
| | - Marianne Patt
- Department of Nuclear Medicine, Faculty of Medicine, University of Augsburg, Augsburg, Germany
| | - Georgine Wienand
- Department of Nuclear Medicine, Faculty of Medicine, University of Augsburg, Augsburg, Germany
| | - Ralph A Bundschuh
- Department of Nuclear Medicine, Faculty of Medicine, University of Augsburg, Augsburg, Germany
| | - Christian H Pfob
- Department of Nuclear Medicine, Faculty of Medicine, University of Augsburg, Augsburg, Germany
| | - Constantin Lapa
- Department of Nuclear Medicine, Faculty of Medicine, University of Augsburg, Augsburg, Germany
| | - Alexander Dierks
- Department of Nuclear Medicine, Faculty of Medicine, University of Augsburg, Augsburg, Germany
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Singh N, McClure EM, Akaike T, Park SY, Huynh ET, Goff PH, Nghiem P. The Evolving Treatment Landscape of Merkel Cell Carcinoma. Curr Treat Options Oncol 2023; 24:1231-1258. [PMID: 37403007 PMCID: PMC11260505 DOI: 10.1007/s11864-023-01118-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2023] [Indexed: 07/06/2023]
Abstract
OPINION STATEMENT Merkel cell carcinoma (MCC) has a high risk of recurrence and requires unique treatment relative to other skin cancers. The patient population is generally older, with comorbidities. Multidisciplinary and personalized care is therefore paramount, based on patient preferences regarding risks and benefits. Positron emission tomography and computed tomography (PET-CT) is the most sensitive staging modality and reveals clinically occult disease in ~ 16% of patients. Discovery of occult disease spread markedly alters management. Newly diagnosed, localized disease is often managed with sentinel lymph node biopsy (SLNB), local excision, primary wound closure, and post-operative radiation therapy (PORT). In contrast, metastatic disease is usually treated systemically with an immune checkpoint inhibitor (ICI). However, one or more of these approaches may not be indicated. Criteria for such exceptions and alternative approaches will be discussed. Because MCC recurs in 40% of patients and early detection/treatment of advanced disease is advantageous, close surveillance is recommended. Given that over 90% of initial recurrences arise within 3 years, surveillance frequency can be rapidly decreased after this high-risk period. Patient-specific assessment of risk is important because recurrence risk varies widely (15 to > 80%: Merkelcell.org/recur) depending on baseline patient characteristics and time since treatment. Blood-based surveillance tests are now available (Merkel cell polyomavirus (MCPyV) antibodies and circulating tumor DNA (ctDNA)) with excellent sensitivity that can spare patients from contrast dye, radioactivity, and travel to a cancer imaging facility. If recurrent disease is locoregional, management with surgery and/or RT is typically indicated. ICIs are now the first line for systemic/advanced MCC, with objective response rates (ORRs) exceeding 50%. Cytotoxic chemotherapy is sometimes used for debulking disease or in patients who cannot tolerate ICI. ICI-refractory disease is the major problem faced by this field. Fortunately, numerous promising therapies are on the horizon to address this clinical need.
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Affiliation(s)
- Neha Singh
- Department of Medicine, Division of Dermatology, University of Washington, 850 Republican Street, Box 358050, Seattle, WA, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA, USA
| | - Erin M McClure
- Department of Medicine, Division of Dermatology, University of Washington, 850 Republican Street, Box 358050, Seattle, WA, USA
- University of South Florida, Morsani College of Medicine, Tampa, FL, USA
| | - Tomoko Akaike
- Department of Medicine, Division of Dermatology, University of Washington, 850 Republican Street, Box 358050, Seattle, WA, USA
| | - Song Y Park
- Department of Medicine, Division of Dermatology, University of Washington, 850 Republican Street, Box 358050, Seattle, WA, USA
| | - Emily T Huynh
- Department of Medicine, Division of Dermatology, University of Washington, 850 Republican Street, Box 358050, Seattle, WA, USA
| | - Peter H Goff
- Department of Medicine, Division of Dermatology, University of Washington, 850 Republican Street, Box 358050, Seattle, WA, USA
- Department of Radiation Oncology, University of Washington, Seattle, WA, USA
| | - Paul Nghiem
- Department of Medicine, Division of Dermatology, University of Washington, 850 Republican Street, Box 358050, Seattle, WA, USA.
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Fagerstedt KW, Vesterinen T, Leijon H, Sihto H, Böhling T, Arola J. Somatostatin receptor expression in Merkel cell carcinoma: correlation with clinical data. Acta Oncol 2023; 62:1001-1007. [PMID: 37540574 DOI: 10.1080/0284186x.2023.2239481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 07/14/2023] [Indexed: 08/06/2023]
Abstract
BACKGROUND Merkel cell carcinoma (MCC) is a rare, high-grade neuroendocrine neoplasm (NEN) of the skin. Somatostatin receptors (SSTRs) are G protein-linked receptors that regulate cell proliferation and growth. SSTRs are expressed in many NENs; however, scant information is available on their expression in MCCs or their association with clinical parameters and patient outcomes. MATERIAL AND METHODS This retrospective study was conducted at Helsinki University Hospital and the University of Helsinki. Using a tissue microarray, we investigated SSTR1-5 expression by immunohistochemistry in 99 MCC tissue samples. Samples were collected between 1983 and 2017 and coupled with the patients' clinical data. RESULTS SSTR2-SSTR5 were detected in 69%, 6%, 4%, and 1% of the tumours, respectively. However, SSTR1 expression was not observed. Cytoplasmic SSTR2 positivity was associated with metastatic disease at the time of diagnosis (p = 0.009), but it did not correlate with disease-specificity or overall survival. CONCLUSION SSTR2-5 expression was observed in MCCs. In particular, SSTR2 expression is clinically valid because it is associated with metastatic disease at the time of diagnosis and can thus serve as a prognostic marker. Moreover, SSTR2 overexpression provides a molecular basis for tumour imaging and treatment with somatostatin analogues.
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Affiliation(s)
- Klaus W Fagerstedt
- Department of Pathology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Tiina Vesterinen
- HUS Diagnostic Centre, Department of Pathology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Helena Leijon
- HUS Diagnostic Centre, Department of Pathology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Harri Sihto
- Department of Pathology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Tom Böhling
- Department of Pathology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Johanna Arola
- Department of Pathology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- HUS Diagnostic Centre, Department of Pathology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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Pini C, Matassa G, Gelardi F, Antunovic L. Now you see me: lights on Merkel Cell Carcinoma. Eur J Hybrid Imaging 2023; 7:6. [PMID: 36935458 PMCID: PMC10025171 DOI: 10.1186/s41824-023-00164-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 02/08/2023] [Indexed: 03/21/2023] Open
Abstract
Merkel Cell Carcinoma (MCC) is a rare primary cutaneous cancer with aggressive behaviour and poor prognosis. Although MCC cells express somatostatin receptors (SSTR), SSTR-targeted PET/CT is not routinely performed in clinical practice. In contrast, the use of [18F]FDG PET/CT is more widespread and its prognostic role is well established. We present the case of an MCC patient suspected recurrence who underwent restaging with both [18F]FDG and [68 Ga]Ga-DOTA-TOC PET/CT. [18F]FDG PET/CT showed pathological uptake only in mediastinal lymph nodes, but SSTR imaging also revealed multiple liver and skeletal metastases, leading to significant disease upstaging and relevant changes in the therapeutic management.
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Affiliation(s)
- Cristiano Pini
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090, Pieve Emanuele, Milan, Italy
- IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089, Rozzano, Milan, Italy
| | - Giovanni Matassa
- IRCCS Policlinico San Matteo di Pavia, Viale Camillo Golgi 19, 27100, Pavia, Italy
| | - Fabrizia Gelardi
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090, Pieve Emanuele, Milan, Italy.
- IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089, Rozzano, Milan, Italy.
| | - Lidija Antunovic
- IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089, Rozzano, Milan, Italy
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