Octreotide as an antineoplastic agent in the treatment of functional and nonfunctional neuroendocrine tumors

Diagnosis and comprehensive treatment of a glucagonoma in a patient with residual intrahepatic metastases postoperatively: A case report and literature review

Glucagonomas are rare neuroendocrine neoplasms of the pancreas with malignant potential. At present, their epidemiology is not entirely clear, so clinicians are not well versed, lacking any consensus on diagnosis or comprehensive treatment. The present study reports the case of a 32-year-old woman hospitalized for recurrent glossitis, perioral dermatitis and necrolytic migratory erythema (NME) of both lower limbs. Imaging studies revealed a low-density nodule (~2 cm) in the tail of the pancreas, as well as multiple space-occupying hepatic lesions. Surgical intervention was then selected, and distal pancreatectomy, splenectomy and palliative metastasectomies were performed. Tissue examination subsequently confirmed a primary pancreatic neuroendocrine tumor (grade 2), metastatic to the liver. The NME resolved postoperatively, aided by intramuscular injections of long-acting release octreotide (30 mg) every 28 days. A series of three percutaneous ablative treatments (microwave ablation) were also undertaken within a 2-year period, targeting the liver metastases. The present condition of the patient is good, with no cutaneous relapse to date. Palliative metastasectomies, in conjunction with ablative treatments and combination somatostatin analog (SSA) use, are unique aspects of this case that, to the best of our knowledge, have yet to be documented in the literature. Surgical palliation may benefit patients with liver involvement and prolong their survival time. Likewise, ablative treatments and SSA injections delivered together not only address hepatic spread, but also control hormone-related symptoms, having a positive impact on prognosis. As glucagonomas are so rare, there is no real agreement on their management. The present study aims to guide clinical practice by adding further to the available data.

Systematic literature review of the antitumor effect of octreotide in neuroendocrine tumors

AIM

To provide a comprehensive examination of the existing evidence of the antitumor effect of long-acting octreotide in neuroendocrine tumors (NETs).

METHODS

A systematic literature review of clinical trials and observational studies was conducted in PubMed, EMBASE, and Cochrane through January 18, 2017. Conference abstracts for 2015 and 2016 from 5 scientific meetings were also searched.

RESULTS

Of 41 articles/abstracts identified, 13 unique studies compared octreotide with active or no treatment. Two of the 13 studies were clinical trials; the remaining were observational studies. The phase 3 Placebo-Controlled, Double-Blind, Prospective, Randomized Study of the Effect of Octreotide long-acting repeatable (LAR) in the Control of Tumor Growth in Patients with Metastatic Neuroendocrine Midgut Tumors clinical trial showed that long-acting octreotide significantly prolonged time to tumor progression compared with placebo in patients with functionally active and inactive metastatic midgut NETs; no statistically significant difference in overall survival (OS) was observed, possibly due to the crossover of placebo patients to octreotide. Retrospective observational studies found that long-acting octreotide use was associated with significantly longer OS than no octreotide use for patients with distant metastases although not for those with local/regional disease.

CONCLUSION

The clinical trial and observational studies with informative evidence support long-acting octreotide’s antitumor effect on time to tumor progression and OS. This review showed the rarity of existing studies assessing octreotide’s antitumor effect and recommends that future research is warranted.

Liver transplantation for metastatic neuroendocrine tumor: a case report and review of the literature

Neuroendocrine tumors are divided into gastrointestinal carcinoids and pancreatic neuroendocrine tumors. The WHO has updated the classification of these lesions and has abandoned the term "carcinoid". Both types of tumors are divided into functional and non-functional tumors. They are characterized by slow growth and frequent metastasis to the liver and may be limited to the liver for long periods. The therapeutic approach to hepatic metastases should consider the number and distribution of the liver metastases as well as the severity of symptoms related to hormone production and tumor bulk. Surgery is generally considered as the first line therapy. In patients with unresectable liver metastases, alternative treatments are dependent on the type and the growth rate. Initial treatments consist of long acting somatostatin analogs and/or interferon. Streptozocin-based chemotherapy is usually reserved for symptomatic patients with rapidly advancing disease, but generally the therapy is poorly tolerated and its effects are short-lived. Locoregional therapy directed such as hepatic-artery embolization and chemoembolization, radiofrequency thermal ablation and cryosurgery, is often used instead of systemic therapy, if the disease is limited to the liver. However, liver transplantation should be considered in patients with neuroendocrine metastases to the liver that are not accessible to curative or cytoreductive surgery and if medical or locoregional treatment has failed and if there are life threatening hormonal symptoms. We report a case of liver transplantation for metastatic neuroendocrine tumor of unknown primary source and provide a detailed review of the world literature on this controversial topic.

Effect of octreotide on cell-cycle kinetics and serum carcinoembryonic antigen level in hepatic metastases of colonic adenocarcinoma

AIM: To study the inhibitory effect of somatostatin analogue (octreotide) on tumor growth.

METHODS: The influence of cell-cycle kinetics on hepatic metastases of BALB/c mice colonic adenocarcinoma (CT26) with octreotide treatment in vivo was investigated by flow cytometry. The serum carcinoembryonic antigen (CEA) levels were also determined.

RESULTS: The results showed that the proliferative index (PI) and the S-phase fraction in hepatic tumors of mice treated with octreotide decreased markedly and that the G₀/G₁ serum CEA phase fraction increased significantly in comparison with the control (P < 0.01). After administration of octreotide, the serum CEA levels were also lower than those in the control group. The incidence of liver metastases in the treated group was lower than that in the control. The body weight loss in the mice was slower and survival was longer in the treated group than in the control group. Furthermore, the changes in PI and the fraction distribution of S-phase or G₀/G_1-phase in cell cycle were closely related to the serum CEA levels.

CONCLUSION: Octreotide may be useful for inhibiting the hepatic metastases of colonic carcinoma.