Medullary thyroid carcinoma (MTC) is a rare malignancy comprising 1–2% of all thyroid cancers in the United States. Approximately 20% of cases are familial, secondary to a germline RET mutation, while the remaining 80% are sporadic, but also harbour a somatic RET mutation in more than half of all cases. Up to 15-20% of patients will present with metastatic disease, and retrospective series report a 10-year survival of 10-40% from time of first metastasis. Historically, systemic therapies for metastatic MTC have been limited and cytotoxic chemotherapy has demonstrated poor objective response rates. However, in the last decade, targeted therapies, particularly multitargeted tyrosine kinase inhibitors (TKIs), have demonstrated prolonged progression-free survival in advanced and progressive MTC. Both cabozantinib and vandetanib have been approved as first-line treatment options in many countries; however, their use is limited by high toxicity rates and dose reductions are often necessary. New generation TKIs, such as selpercatinib or pralsetinib, that exhibit selective activity against RET, have recently been approved as a second-line treatment option, and they exhibit a more favourable side-effect profile. Peptide receptor radionuclide therapy (PRRT) or immune checkpoint inhibitors may also constitute potential therapeutic options in specific clinical settings. In this review we aim to present all current therapeutic options available for patients with progressive MTC, as well as the new or as yet experimental treatments.
Anna Angelousi, Aimee R Hayes, Eleftherios Chatzellis, Gregory A Kaltsas, and Ashley B. Grossman
Krystallenia I Alexandraki, Gregory A Kaltsas, Simona Grozinsky-Glasberg, Eleftherios Chatzellis, and Ashley B Grossman
Gastrointestinal neuroendocrine neoplasms (GI-NENs) are increasingly being recognised, while appendiceal NENs (aNENs) currently constitute the third most common GI-NEN. Appendiceal NENs are generally considered to follow an indolent course with the majority being localised at diagnosis. Thus, the initial surgical approach is not that of a planned oncological resection. Due to the localised nature of the disease in the majority of cases, subsequent biochemical and radiological assessment are not routinely recommended. Histopathological criteria (size, mesoappendiceal invasion, Ki-67 proliferation index, neuro- and angio-invasion) are mainly used to identify those patients who are also candidates for a right hemicolectomy. Goblet cell carcinoids are a distinct entity and should be treated as adenocarcinomas. Despite the absence of any substantial prospective data regarding optimal management and follow-up, recent consensus statements and guidelines have been published. The purpose of this review is to overview the published studies on the diagnosis and management of appendiceal NENs and to suggest a possible management protocol.
Gregory A Kaltsas, Janet L Cunningham, Sture E Falkmer, Lars Grimelius, and Apostolos V Tsolakis
Connective tissue growth factor (CTGF) and IGF1 are both expressed in a variety of tumours and are involved in tumourigenesis. However, information about their expression in the gastrointestinal (GI) neuroendocrine (NE) cells and tumours is mainly limited, with the exception of midgut carcinoids where abundant CTGF expression has been demonstrated. Normal mucosa specimens from stomach and ileum, as well as tumour tissue specimens from gastric NE tumours (GNETs; n=58) and midgut NETs (n=38) were included. Immunohistochemical techniques were used to investigate the possible expression of CTGF and IGF1 in GI NE cells and tumours. The latter results were correlated with various clinico-biochemical and histopathological variables. CTGF was expressed in a proportion of NE cells of the normal GI mucosa but not in enterochromaffin-like (ECL) cells, whereas IGF1 was undetectable. CTGF was absent in the foci of ECL cell hyperplasia, and in most of the poorly differentiated carcinomas, but present in some GNETs (mainly in type III ECL cell carcinoids (ECL-CCs)) and in all but one midgut NETs. CTGF correlated with tumour stage in well-differentiated GNETs and with size larger than 1 cm but only in the subgroup of type I ECL-CCs. IGF1 was detected in the foci of ECL cell hyperplasia and in all GI NETs. These findings suggest that both CTGF and IGF1 may be involved in the neoplastic transformation of GI NE cells, whereas IGF1 may play an important role even at early stage.
Gregory A Kaltsas, Jane Evanson, Alexandra Chrisoulidou, and Ashley B Grossman
The sellar and parasellar region is an anatomically complex area where a number of neoplastic, inflammatory, infectious, developmental and vascular diseases can develop. Although most sellar lesions are due to pituitary adenomas, a number of other pathologies involving the parasellar region can present in a similar manner. The diagnosis of such lesions involves a multidisciplinary approach, and detailed endocrinological, ophthalmological, neuroimaging, neurological and finally histological studies are required. Correct diagnosis prior to any intervention is essential as the treatment of choice will be different for each disorder, particularly in the case of primary malignant parasellar tumours. The complexity of structures that define the parasellar region can produce a variety of neoplastic processes, the malignant potential of which relies on histological grading. In the majority of parasellar tumours, a multimodal therapeutic approach is frequently necessary including surgery, radiotherapy, primary or adjuvant medical treatment and replacement of apparent endocrine deficits. Disease-specific medical therapies are mandatory in order to prevent recurrence or further tumour growth. This is particularly important as neoplastic lesions of the parasellar region tend to recur after prolonged follow-up, even when optimally treated. Apart from the type of treatment, identification of clinical and radiological features that could predict patients with different prognosis seems necessary in order to identify high-risk patients. Due to their rarity, central registration of parasellar tumours is required in order to be able to provide evidence-based diagnostic and mainly therapeutic approaches.
Kimberly Kamp, Brenda Gumz, Richard A Feelders, Dik J Kwekkeboom, Gregory Kaltsas, Frederico P Costa, and Wouter W de Herder
Although 177Lu-octreotate is an effective treatment for patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs), some patients will fail or develop disease progression necessitating further treatment. We examined whether the safety and efficacy of everolimus after prior treatment with 177Lu-octreotate is different from the published safety profile of everolimus in GEP-NETs. In this multicenter study, 24 GEP-NET patients were included. Adverse events were assessed according to the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE), version 3.0. Tumor response was measured according to the Response Evaluation Criteria in Solid Tumors (RECIST), version 1.0. Major clinical adverse events (grade 3 or 4) during treatment with everolimus were hyperglycemia (20.8%), fatigue (8.3%), thrombocytopenia (8.3%), and elevated alanine transaminase levels (8.3%). By radiological review, there were four partial responses (16.7%), five patients (62.5%) with stable disease, and three patients (12.5%) with progressive disease. For two patients (8.3%), no data on tumor response were available. Median progression-free survival (PFS) was 13.1 months (95% CI, 11.5–21.2). Median PFS of the current study was longer when compared with the RADIANT-3 trial (13.1 vs 11.4 months) and shorter when compared with the RADIANT-1 trial (13.1 vs 16.7 months). In conclusion, the safety profile of everolimus is not influenced by previous treatment with peptide receptor radiotherapy.
Krystallenia I Alexandraki, Ariadni Spyroglou, Stylianos Kykalos, Kosmas Daskalakis, Georgios Kyriakopoulos, Georgios C Sotiropoulos, Gregory A Kaltsas, and Ashley B Grossman
Following improvements in the management and outcome of neuroendocrine neoplasms (NENs) in recent years, we see a subset, particularly of pancreatic NENs, which become more aggressive during the course of the disease. This is reflected by an increase in the Ki-67 labelling index, as a marker of proliferation, which may lead to an occasion of increase in grading, but generally does not appear to be correlated with histologically confirmed dedifferentiation. A systematic review of the literature was performed in PubMed, Cochrane Library, and Embase until May 2020 to identify cases that have behaved in such a manner. We screened 244 articles: only seven studies included cases in their cohort, or in a subset of the cohort studied, with a proven increase in the Ki-67 during follow-up through additional biopsy. In addition to these studies, we have also tried to identify possible pathophysiological mechanisms implicated in advanced NENs, although currently no studies appear to have addressed the mechanisms implicated in the switch to a more aggressive biological phenotype over the course of the disease. Such progression of the disease course may demand a change in the management. Summarising the overall evidence, we suggest that future studies should concentrate on changes in the molecular pathways during disease progression with sequential biopsies in order to shed light on the mechanisms that render a neoplasm more aggressive than its initial phenotype or genotype.