GASTROENTEROPANCREATIC NEUROENDOCRINE TUMORS (GEP-NETs) - APPROACH TO DIAGNOSIS AND MANAGEMENT

PET/CT and PET/MRI in neuroendocrine neoplasms

Advanced molecular imaging has come to play an integral role in the management of gastro-entero-pancreatic neuroendocrine neoplasms (GEP-NENs). Somatostatin receptor (SSTR) PET has now emerged as the reference standard for the evaluation of NENs and is particularly critical in the context of peptide receptor radionuclide therapy (PRRT) eligibility. SSTR PET/MRI with liver-specific contrast agent has a strong potential for one-stop-shop multiparametric evaluation of GEP-NENs. 18F-FDG is a complementary radiotracer to SSTR, especially in the context of high-grade neuroendocrine neoplasms. Knowledge gaps in quantitative evaluation of molecular imaging studies and their role in assessment of response to PRRT and combination therapies are active research areas. Novel radiotracers have the potential to overcome existing limitations in the molecular imaging of GEP-NENs. The purpose of this article is to provide an overview of the current trends, pitfalls, and recent advancements of molecular imaging for GEP-NENs.

Inflammation Related to Obesity in the Etiopathogenesis of Gastroenteropancreatic Neuroendocrine Neoplasms

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are rare neoplasms, which, due to their heterogeneous nature, non-specific symptoms, and lack of specific tumor markers pose many diagnostic and clinical challenges. In recent years, the effectiveness of GEP-NEN diagnosis has increased, which is probably associated with the greater availability of diagnostic tests and the cooperation of many experienced specialists in various scientific disciplines. In addition to the possible genetic etiology, the cause of GEP-NET development is not fully understood. Inflammation and obesity are known risks that contribute to the development of many diseases. Chronic inflammation accompanying obesity affects the hormonal balance and cell proliferation and causes the impairment of the immune system function, leading to neoplastic transformation. This review explores the role of inflammation and obesity in GEP-NETs. The exact mechanisms inducing tumor growth are unknown; however, the profile of inflammatory factors released in the GEP-NET tumor microenvironment is responsible for the progression or inhibition of tumor growth. Both the excess of adipose tissue and the impaired function of the immune system affect not only the initiation of cancer but also reduce the comfort and lifetime of patients.

Estimation of Health-Related Utilities for 177Lu-DOTATATE in GEP-NET Patients Using Utilities Mapped from EORTC QLQ-C30 to EQ-5D-3L and QLU-C10D Utilities

BACKGROUND

Gastroenteropancreatic neuroendocrine tumours (GEP-NET) are a rare, life-threatening type of cancer. The survival benefit of ¹⁷⁷Lu-DOTATATE has been demonstrated in GEP-NET patients. Health technology assessment bodies require data on health-related utility impacts of treatment. A cancer-specific instrument, EORTC QLQ-C30, was used to collect the data for ¹⁷⁷Lu-DOTATATE within clinical studies, but utility-based instruments were not included.

OBJECTIVE

The main aim of this study was to compare EQ-5D-3L and QLU-C10D utilities obtained from EORTC QLQ-C30 using two different approaches. A secondary aim was to analyse the EQ-5D-3L and QLU-C10D utilities of patients treated with ¹⁷⁷Lu-DOTATATE versus best supportive care. A supplementary aim was to evaluate the effect of ¹⁷⁷Lu-DOTATATE on patients' health-related utility over time.

METHODS

Three datasets were used for the analysis. NETTER-1 is a clinical trial, whilst ERASMUS and Guy's and St. Thomas (GStT) are real-world datasets. Two mapping algorithms (response mapping and ordinary least square regression) were applied to generate EQ-5D-3L utilities from EORTC QLQ-C30. An algorithm was used to obtain QLU-C10D utilities from EORTC QLQ-C30.

RESULTS

In all studies, EQ-5D-3L utilities were higher than QLU-C10D utilities at most time points measured, although the magnitude of the differences was small. In NETTER-1, EQ-5D-3L and QLU-C10D utilities were higher in the ¹⁷⁷Lu-DOTATATE arm compared with the octreotide long-acting release (LAR) arm, overall and pre-progression. In all studies, patients' health-related utilities seem to be maintained over time.

CONCLUSION

There were small differences between EQ-5D-3L and QLU-C10D utilities, but these did not translate to relative differences over time or between groups. In NETTER-1, patients in the ¹⁷⁷Lu-DOTATATE arm had higher health-related utilities than patients in the octreotide LAR arm. Health-related utility may at least remain maintained in patients with GEP-NET receiving ¹⁷⁷Lu-DOTATATE.

Histopathologist-level quantification of Ki-67 immunoexpression in gastroenteropancreatic neuroendocrine tumors using semiautomated method

The role of Ki-67 index in determining the prognosis and management of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) has become more important yet presents a challenging assessment dilemma. Although the precise method of Ki-67 index evaluation has not been standardized, several methods have been proposed, and each has its pros and cons. Our study proposes an imaging semiautomated informatics framework [semiautomated counting (SAC)] using the popular biomedical imaging tool "ImageJ" to quantify Ki-67 index of the GEP-NETs using camera-captured images of tumor hotspots. It aims to assist pathologists in achieving an accurate and rapid interpretation of Ki-67 index and better reproducibility of the results with minimal human interaction and calibration. Twenty cases of resected GEP-NETs with Ki-67 staining that had been done for diagnostic purposes have been randomly selected from the pathology archive. All of these cases were reviewed in a multidisciplinary cancer center between 2012 and 2019. For each case, the Ki-67 immunostained slide was evaluated and five camera-captured images at 40 × magnification were taken. Prints of images were used by three pathologists to manually count the tumor cells. The digital versions of the images were used for the semiautomated cell counting using ImageJ. Statistical analysis of the Ki-67 index correlation between the proposed method and the MC revealed strong agreement on all the cases evaluates ( n = 20 ), with an intraclass correlation coefficient of 0.993, "95% CI: 0.984 to 0.997." The results obtained from the SAC are promising and demonstrate the capability of this methodology for the development of reproducible and accurate semiautomated quantitative pathological assessments. ImageJ features are investigated carefully and accurately fine-tuned to obtain the optimal sequence of steps that will accurately calculate Ki-67 index. SAC is able to accurately grade all the cases evaluated perfectly mating histopathologists' manual grading, providing reliable and efficient solution for Ki-67 index assessment.