Targeting neuroendocrine tumors with octreotide and lanreotide: Key points for clinical practice from NET specialists

Octreotide and lanreotide are the two somatostatin analogs (SSA) currently available in clinical practice. They have been approved first to control the clinical syndrome (mainly carcinoid syndrome) associated with functioning neuroendocrine tumors (NET) and later for tumor growth control in advanced low/intermediate grade NET. Although evidence regarding their role, especially as antiproliferative therapy, has been increasing over the years some clinical indications remain controversial. Solicited by AIOM (Italian Association of Medical Oncology) a group of clinicians from various specialties, including medical oncology, endocrinology, and gastroenterology, deeply involved in NET for their clinical and research activity, addressed eight open questions, critically reviewing evidence and guidelines and sharing clinical take-home messages. The questions regarded the use of long-acting octreotide and lanreotide in the following settings: functioning and non-functioning NET refractory to label dose, first-line metastatic pulmonary NET, combination with other therapy with an antiproliferative intent, maintenance in NET responding to other therapies, adjuvant treatment, Ki-67-related cut-off, somatostatin receptor imaging, safety, and feasibility. The level of evidence is not absolute for the majority of these clinical contexts, so it is recommended to distinguish routine versus sporadic utilization in very selected cases. Mention of such specific issues by the main European guidelines (ENETS, European Neuroendocrine Tumor Society, and ESMO, European Society for Medical Oncology) was explored and their position reported. However, different clinical decisions on single patients could be made if the case is carefully discussed within a NET-dedicated multidisciplinary team.

Integrating Functional Imaging and Molecular Profiling for Optimal Treatment Selection in Neuroendocrine Neoplasms (NEN)

PURPOSE OF REVIEW

Gastroenteropancreatic NEN (GEP-NEN) are group of malignancies with significant clinical, anatomical and molecular heterogeneity. High-grade GEP-NEN in particular present unique management challenges.

RECENT FINDINGS

In the current era, multidisciplinary management with access to a combination of functional imaging and targeted molecular profiling can provide important disease characterisation, guide individualised management and improve patient outcome. Multiple treatment options are now available, and combination and novel therapies are being explored in clinical trials. Precision medicine is highly relevant for a heterogenous disease like NEN. The integration of dual-tracer functional PET/CT imaging, molecular histopathology and genomic data has the potential to be used to gain a more comprehensive understanding of an individual patient's disease biology for precision diagnosis, prognostication and optimal treatment allocation.

Peptide Receptor Radionuclide Therapy: Looking Back, Looking Forward

Peptide receptor radionuclide therapy (PRRT) is a highly effective anti-cancer treatment modality for patients with non-resectable, metastasized neuroendocrine tumors (NETs). During PRRT, specific receptors that are overexpressed on the cancer cells are targeted with a peptide labeled with a DNA-damaging radionuclide. Even though PRRT is a powerful treatment for metastasized NET patients, the majority still cannot be cured at this stage of the disease. Hence, many investigators focus on improving the therapeutic efficacy of this therapy. Improving PRRT can, for example, be achieved by using other radionuclides with different physical properties, by combining PRRT with radiosensitizing agents or by radiolabeling peptides with different characteristics. However, due to lack of extensive knowledge of radiobiological responses of cancer cells to PRRT, biological parameters that influence absorbed dose or that might even elicit insensitivity to therapy remain elusive and the context in which these improvements will be successful warrants further investigation. In this review, we will discuss the development of PRRT, its clinical merits in current treatment and future perspectives. We will highlight different radionuclides and their benefits and pitfalls, as well as different peptide-conjugates that hold these radionuclides. We will zoom in on the latest developments regarding combinatorial treatments and how investigators from different disciplines such as dosimetry and radiobiology are now joining forces to improve PRRT for NETs.

Second primary neoplasms in patients with lung and gastroenteropancreatic neuroendocrine neoplasms: Data from a retrospective multi-centric study

BACKGROUND

Patients with sporadic neuroendocrine neoplasms may exhibit a higher risk of a second primary tumor than the general population.

AIM

This study aimed to analyze the occurrence of second primary malignancies.

METHODS

A retrospective cohort of 2757 patients with sporadic lung and gastro-entero-pancreatic neuroendocrine neoplasms, managed at eight Italian tertiary referral Centers, was included.

RESULTS

Between 2000 and 2019, a second primary malignancy was observed in 271 (9.8%) neuroendocrine neoplasms patients with 32 developing a third tumor. There were 135 (49.8%) females and the median age was 64 years. The most frequent locations of the second tumors were breast (18.8%), prostate (12.5%), colon (9.6%), blood tumors (8.5%), and lung (7.7%). The second primary tumor was synchronous in 19.2% of cases, metachronous in 43.2%, and previous in 37.6%. As concerned the neuroendocrine neoplasms, the 5- and 10-year survival rates were 87.8% and 74.4%, respectively. PFS for patients with a second primary malignancy was shorter than for patients without a second primary malignancy. Death was mainly related to neuroendocrine neoplasms.

CONCLUSION

In NEN patients the prevalence of second primary malignancies was not negligible, suggesting a possible neoplastic susceptibility. Overall survival was not affected by the occurrence of a second primary malignancy.

Appendicular neoplasms and consequences in patients undergoing surgery for suspected acute appendicitis

INTRODUCTION

In patients treated with an appendectomy for acute appendicitis, the specimen is generally sent for histological evaluation. In an era of increasing non-operative treatment for acute appendicitis, it is important to know the incidence, the diagnostic accuracy, and treatment consequences of appendicular neoplasms that are found in acute appendicitis. We hypothesize that pre- and intra-operative parameters might predict an appendicular neoplasm.

METHODS

Data was used from our previous prospective observational cohort study. All patients undergoing surgery for suspected acute appendicitis were included. The primary outcome was the incidence of appendicular neoplasms in patients operated for acute appendicitis. Secondary outcomes were pre-operative diagnostics and imaging outcomes, intra-operative surgical judgment, and postoperative management and outcome. Possible predictors of an appendicular neoplasm were identified and used in multivariable logistic regression. Patients with an appendicular neoplasm were followed for 3 years after initial appendectomy.

RESULTS

A total of 1975 patients underwent surgery for suspected acute appendicitis and in 98.3% (1941/1975) the appendix was removed. In 1.5% (30/1941) of these patients, an appendicular neoplasm was found. Among the malignant neoplasms, the majority were grade 1 neuroendocrine tumors (NET) in 65% (13/20). On pre-operative imaging, there was no suspicion of malignancy. In three cases, there was an intra-operative suspicion of malignancy. Multivariable analysis showed only age as an independent predictor for appendicular neoplasms. No recurrent or new malignancy was found during follow-up.

DISCUSSION

The incidence of appendicular neoplasm in patients undergoing an acute appendectomy is very low and clinical risk factors could not be identified.

Measurement variability of liver metastases from neuroendocrine tumors on different magnetic resonance imaging sequences

PURPOSE

To assess dimension measurement variability of liver metastases from neuroendocrine tumors (LMNET) on different magnetic resonance imaging (MRI) sequences.

MATERIAL AND METHODS

In this institutional review board-approved retrospective study from January 2011 to December 2012, all liver MRI examinations performed at our department in patients with at least one measurable LMNET according to response evaluation criteria in solid tumors (RECIST1.1) were included. Up to two lesions were selected on T2-weighted MR images. Three reviewers independently measured long axes of 135 hepatic metastases in 30 patients (16 men, 14 women, mean age 61±11.4 (SD) years; range 28-78 years), during two separate reading sessions, on T2-weighted, diffusion-weighted MRI (DWI) (b; 50, 400, 800 s/mm²) and arterial, portal and late phases after intravenous administration of a gadolinium chelate. Intraclass-correlation coefficients and Bland-Altman plots were used to assess intra-and interobserver variability.

RESULTS

Intra- and interobserver agreements ranged between 0.87-0.98, and 0.88-0.97, respectively. Intersequence agreements ranged between 0.92 [95%CI: 0.82-0.98] and 0.98 [95%CI: 0.93-0.99]. 95% limits of agreement for measurements were -10.2%,+8.9% for DWI (b=50s/mm²) versus -21.9%,+24.2% and -15.8,+17.2% for arterial and portal phases, respectively.

CONCLUSION

An increase<9% in measurement and a decrease of -10% on DWI should not be considered as true changes, with 95% confidence, versus 24% and -22% on arterial and 17%, -16% on portal phases, respectively. DWI might thus be the most reliable MR sequence for monitoring size variations of LMNETs.

Clinicopathologic study of neuroendocrine tumors of gastroenteropancreatic tract: a single institutional experience

BACKGROUND

The gastroenteropancreatic neuroendocrine tumors (GEPNET) have a characteristic histologic appearance unrelated of the exact site of origin. However the behavior of these tumors are different in each of these sites. In this article we study the clinicopathological features of GEPNET. These tumors were classified and graded according to WHO 2010 criteria. The immunohistochemical (IHC) features were evaluated and the grade of the tumor was correlated with Ki67.

METHODS

A total of 40 cases of GEPNET diagnosed on biopsies as well as resected specimens were analyzed from January 2012 to June 2015.

RESULTS

There were 28 resected specimens and 12 biopsies. Majority of the gastric neuroendocrine tumors (NET) showed classic morphology of cells arranged in islands. There were 3 cases each of grade 1 and grade 2 and one was diagnosed as mixed adenoneuroendocrine carcinoma (MANEC). All the duodenal NET were well differentiated (grade 1). There were 8 cases in colon and rectum, of which 4 cases were grade 3 and 3 cases were grade 2. Majority of the pancreatic tumors were grade 1. The mean mitotic count along with ki67 had good correlation in NET of stomach, duodenum colon and rectum.

CONCLUSIONS

The most common site was small intestine followed by pancreas. Majority of the tumors were NET G1. Tumors from colorectal region were mostly NEC G3. There was a strong correlation by spearman correlation analysis between Ki67 and mitotic count and moderate correlation between ki67 and tumor grade as well as mitotic rate and tumor grade. Ki67 was helpful in grading these tumors.

Role of 18F-fluorodeoxyglucose PET in the study of neuroendocrine tumors

The most widely used PET radiopharmaceutical in daily clinical practice is (18)F-fluorodeoxyglucose (FDG). The evaluation of glycolytic metabolism by (18)F-FDG is potentially useful in identifying high-risk patients with aggressive neuroendocrine disease associated with a poor outcome. Although the use of new somatostatin analogues labeled with 68-Gallium for PET has significantly increased the sensitivity of NET imaging compared with single photon emission computed tomography and (18)F-FDG-PET, (18)F-FDG may retain an important role in managing patients with NETs owing to its high prognostic value and its higher sensitivity in delineating disease extent, especially in aggressive and high-grade tumors.