Somatostatin receptor radionuclide therapy in neuroendocrine tumors

Targeted radionuclide therapy in endocrine-related cancers: advances in the last decade

Targeted radionuclide therapy plays an increasingly important role in managing endocrine-related tumors and significantly advances the therapeutic landscape for patients with these diseases. With increasing FDA-approved therapies and advances in the field, come an increased knowledge of the potential for long-term toxicities associated with these therapies and the field must develop new strategies to increase potency and efficacy while individualizing the selection of patients to those most likely to respond to treatment. Novel agents and modalities of therapy are also being explored. This review will discuss the current landscape and describe the avenues for growth in the field currently being explored.

Clinical Advances and Perspectives in Targeted Radionuclide Therapy

Targeted radionuclide therapy has become increasingly prominent as a nuclear medicine subspecialty. For many decades, treatment with radionuclides has been mainly restricted to the use of iodine-131 in thyroid disorders. Currently, radiopharmaceuticals, consisting of a radionuclide coupled to a vector that binds to a desired biological target with high specificity, are being developed. The objective is to be as selective as possible at the tumor level, while limiting the dose received at the healthy tissue level. In recent years, a better understanding of molecular mechanisms of cancer, as well as the appearance of innovative targeting agents (antibodies, peptides, and small molecules) and the availability of new radioisotopes, have enabled considerable advances in the field of vectorized internal radiotherapy with a better therapeutic efficacy, radiation safety and personalized treatments. For instance, targeting the tumor microenvironment, instead of the cancer cells, now appears particularly attractive. Several radiopharmaceuticals for therapeutic targeting have shown clinical value in several types of tumors and have been or will soon be approved and authorized for clinical use. Following their clinical and commercial success, research in that domain is particularly growing, with the clinical pipeline appearing as a promising target. This review aims to provide an overview of current research on targeting radionuclide therapy.

Case Report: Octreotide plus CVD chemotherapy for the treatment of multiple metastatic paragangliomas after double resection for functional bladder paraganglioma and urothelial papilloma

Background

Metastatic pheochromocytomas and paragangliomas are rare neuroendocrine tumors with a poor prognosis. Bladder paraganglioma concomitant with urothelial papilloma is even rarer. However, the rate of tumor response to cyclophosphamide-vincristine-dacarbazine (CVD) chemotherapy and 5-year overall survival for patients with metastatic PPGLs remained lower. We described, for the first time, a case of a patient with multiple metastatic bladder PGL who received octreotide LAR combined with CVD chemotherapy after urological surgery and then octreotide therapy was continued during follow-up.

Case presentation

A 43-year-old male patient was admitted to the urology department for frequent micturition syncope concomitant with malignant hypertension. Preoperative findings were elevated levels of normetanephrine in 24-h urine or plasma. CT and MRI indicated diagnosis of suspicious bladder paraganglioma. Transurethral resection of bladder tumor combined with laparoscopic partial cystectomy was performed successfully after preoperative phenoxybenzamine with aggressive volume repletion for 7 days. The result of postoperative pathology was immediate-risk functional bladder paraganglioma (T2N0M0, Stage II) concomitant with urothelial papilloma, and the immunohistochemistry results of PPGL were positive for Ki-67 (15%), SDHB, CgA, and SSTR2. The patient achieved enhanced recovery with normal urination and no syncope after surgery. However, the results of ¹⁸F-FDG and ¹⁸F-DOTATATE PET/CT found that the metastatic localizations of bladder PGLs were in the liver, lung, and bones at the 8th month after surgery. The patient received octreotide long-acting repeatable plus six courses of CVD chemotherapy for 6 months, and then octreotide therapy was continued every 3 months until now. Metastatic localizations were stable in CT scans, and vanillylmandelic acid in 24-h urine was maintained at lower levels during follow-up.

Conclusion

Octreotide long-acting repeatable plus CVD chemotherapy after surgery could achieve stable disease in the case with multiple metastatic bladder PGLs, and the following octreotide therapy could maintain a state of stable disease during the period of 6-month follow-up.

A multidisciplinary approach to the work up and management of pulmonary carcinoid tumors and DIPNECH: a narrative review

Background and Objective

Low and intermediate grade neuroendocrine tumors of the lung are uncommon malignancies representing 2% of all lung cancers. These are termed typical and atypical pulmonary carcinoid tumors. These can arise in the setting of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH). The presentation, workup, management and outcomes of patients with these tumors can overlap with more common lung cancers but differ in that many of these patients have a prolonged clinical course. The objective of this narrative review is to summarize the literature and provide evidence and expert-based algorithms for work up and treatment of pulmonary carcinoids and DIPNECH.

Methods

A search of PubMed and Web of Science databases ending April 15, 2022, with the following keywords "lung carcinoid", "DIPNECH", "lung neuroendocrine," and "bronchopulmonary carcinoid".

Key Content and Findings

Pulmonary carcinoid tumors benefit from a multidisciplinary approach. Pre-treatment imaging with contrast-enhanced computed tomography, and DOTATATE positron emission tomography is required. Surgical resection is the gold standard for curative intent, and possibly including sublobar resections. Patients can recur or develop new primaries thus emphasizing the importance of surveillance; national guidelines recommend at least a 10-year follow up. A growing body of literature support the use of endobronchial therapy, with long responses documented. Systemic therapy consists of everolimus, somatostatin analogs, peptide receptor radionuclide therapy, and chemotherapy. Diffuse idiopathic pulmonary neuroendocrine tumor cell hyperplasia is rare, but series suggest somatostatin analogs may confer clinical benefit.

Conclusions

Pulmonary carcinoid tumors and DIPNECH are rare. Despite lack of regulatory approvals for advanced disease, multiple options are available but should be sequenced according to the clinical status and disease biology. Each patient should be discussed in a multidisciplinary setting and clinical trials should be considered if available.

Somatostatin plus Ulinastatin in the Treatment of Severe Acute Pancreatitis and Its Effect on Serum Cytokine Levels

Objective

To investigate the effect of somatostatin combined with ulinastatin in the treatment of patients with severe acute pancreatitis and its effect on serum cytokine levels.

Methods

This study is a retrospective trial. One hundred patients with severe acute pancreatitis in our hospital between March 2020 and May 2021 were recruited and assigned into the control group (ulinastatin alone) and experimental group (somatostatin plus ulinastatin) according to different treatment methods, 50 cases each. The clinical efficacy and serum cytokine levels of the two groups were compared.

Results

Somatostatin plus ulinastatin was associated with a higher total effective rate versus ulinastatin alone (p < 0.05). After treatment, the experimental group observed significantly better interleukin-10 (IL-10), interleukin-18 (IL-18), and tumor necrosis factor-α (TNF-α) when compared with those in the control group (p < 0.05); somatostatin plus ulinastatin resulted in better serum amylase, blood calcium, blood urea nitrogen, blood sugar, and white blood cell count versus ulinastatin alone (p < 0.05).

Conclusion

Somatostatin plus ulinastatin is a viable alternative in the treatment of patients with severe acute pancreatitis, with a remarkable efficacy profile. It is worthy of clinical application.

Combination of [177Lu]Lu-DOTA-TATE Targeted Radionuclide Therapy and Photothermal Therapy as a Promising Approach for Cancer Treatment: In Vivo Studies in a Human Xenograft Mouse Model

Peptide receptor radionuclide therapy (PRRT) relies on α- and β-emitting radionuclides bound to a peptide that commonly targets somatostatin receptors (SSTRs) for the localized killing of tumors through ionizing radiation. A Lutetium-177 (¹⁷⁷Lu)-based probe linked to the somatostatin analog octreotate ([¹⁷⁷Lu]Lu-DOTA-TATE) is approved for the treatment of certain SSTR-expressing tumors and has been shown to improve survival. However, a limiting factor of PRRT is the potential toxicity derived from the high doses needed to kill the tumor. This could be circumvented by combining PRRT with other treatments for an enhanced anti-tumor effect. Photothermal therapy (PTT) relies on nanoparticle-induced hyperthermia for cancer treatment and could be a useful add-on to PRRT. Here, we investigate a strategy combining [¹⁷⁷Lu]Lu-DOTA-TATE PRRT and nanoshell (NS)-based PTT for the treatment of SSTR-expressing small-cell lung tumors in mice. Our results showed that the combination treatment improved survival compared to PRRT alone, but only when PTT was performed one day after [¹⁷⁷Lu]Lu-DOTA-TATE injection (one of the timepoints examined), showcasing the effect of treatment timing in relation to outcome. Furthermore, the combination treatment was well-tolerated in the mice. This indicates that strategies involving NS-based PTT as an add-on to PRRT could be promising and should be investigated further.

Net theranostics

Theranostics is a term coined by combining the words “therapeutics” and “diagnostics,” referring to single chemical entities developed to deliver therapy and diagnosis simultaneously. Neuroendocrine tumors are rare cancers that occur in various organs of the body, and they express neuroendocrine factors such as chromogranin A and somatostatin receptor. Somatostatin analogs bind to somatostatin receptor, and when combined with diagnostic radionuclides, such as gamma‐emitters, are utilized for diagnosis of neuroendocrine tumor. Somatostatin receptor scintigraphy when combined with therapeutic radionuclides, such as beta‐emitters, are effective in treating neuroendocrine tumor as peptide receptor radionuclide therapy. Somatostatin receptor scintigraphy and peptide receptor radionuclide therapy are some of the most frequently used and successful theranostics for neuroendocrine tumor. In Japan, radiopharmaceuticals are regulated under a complex law system, creating a significant drug lag, which is a major public concern. It took nearly 10 years to obtain the approval for somatostatin receptor scintigraphy and peptide receptor radionuclide therapy use by the Japanese government. In 2021, ¹¹¹Lu‐DOTATATE (Lutathera), a drug for peptide receptor radionuclide therapy, was covered by insurance in Japan. In this review, we summarize the history of the development of neuroendocrine tumor theranostics and theranostics in general, as therapeutic treatment for cancer in the future. Furthermore, we briefly address the Japanese point of view regarding the development of new radiopharmaceuticals.

Bombesin Receptor Family Activation and CNS/Neural Tumors: Review of Evidence Supporting Possible Role for Novel Targeted Therapy

G-protein-coupled receptors (GPCRs) are increasingly being considered as possible therapeutic targets in cancers. Activation of GPCR on tumors can have prominent growth effects, and GPCRs are frequently over-/ectopically expressed on tumors and thus can be used for targeted therapy. CNS/neural tumors are receiving increasing attention using this approach. Gliomas are the most frequent primary malignant brain/CNS tumor with glioblastoma having a 10-year survival <1%; neuroblastomas are the most common extracranial solid tumor in children with long-term survival<40%, and medulloblastomas are less common, but one subgroup has a 5-year survival <60%. Thus, there is an increased need for more effective treatments of these tumors. The Bombesin-receptor family (BnRs) is one of the GPCRs that are most frequently over/ectopically expressed by common tumors and is receiving particular attention as a possible therapeutic target in several tumors, particularly in prostate, breast, and lung cancer. We review in this paper evidence suggesting why a similar approach in some CNS/neural tumors (gliomas, neuroblastomas, medulloblastomas) should also be considered.