Streptozocin/5-fluorouracil chemotherapy of pancreatic neuroendocrine tumours in the era of targeted therapy

[Gastrointestinal neuroendocrine tumors: update 2024]

Gastrointestinal neuroendocrine tumours (NETs) are rare and clinically heterogeneous. From a diagnostic perspective, well-differentiated tumours must be distinguished from poorly differentiated neuroendocrine carcinomas. The disease may be associated with autonomous hormone secretion by the tumour, and the resulting syndromes are often associated with reduced survival. Somatostatin analogues form the backbone of antiproliferative and antisecretory treatment alongside local ablative procedures. In pancreatic NET, prospective studies confirm the value of specific chemotherapy, particularly in terms of higher remission rates. New tyrosine kinase inhibitors are an option for patients that have failed to respond to standard treatments. Inhibition of HIF2-alpha is an emerging effective treatment option for patients with von Hippel-Lindau-syndrome associated tumours, e.g. pancreatic NET. Radioligand therapy is an established second-line option for advanced NET of the small intestine, and recent study results support its use in pancreatic NET in earlier-line treatment. Due to the complexity of the disease, management of NET patients should be performed in close collaboration with a specialized multidisciplinary team.

Efficacy and safety of streptozocin-based chemotherapy for gastroenteropancreatic neuroendocrine tumors in Japanese clinical practice

BACKGROUND

Streptozocin has been used to treat neuroendocrine tumors in Europe and the USA; however, its actual status in Japan has not been fully clarified owing to the rarity of this disease and the relatively recent approval of streptozocin in Japan.

METHODS

We retrospectively analyzed 53 patients with gastroenteropancreatic neuroendocrine tumors who were treated with streptozocin-based chemotherapy at two Japanese hospitals between January 2004 and June 2023.

RESULTS

The overall response and disease control rates were 27.7 and 74.5%, respectively, and the median progression-free survival and overall survival were 7.1 and 20.3 months, respectively. Performance status ≥1 showed a significant negative correlation with progression-free survival, and performance status ≥1 and liver tumor burden ≥25% showed a significant negative correlation with overall survival. No significant differences were observed in the treatment response between pancreatic and gastrointestinal neuroendocrine tumors. No treatment-related serious adverse events were observed; however, 87.7% of patients expressed a decrease in the estimated glomerular filtration rate, which negatively correlated with the duration of streptozocin treatment (r = 0.43, P = 0.0020). In the streptozocin re-administration group (n = 5), no differences were found in efficacy between the initial and second streptozocin treatments.

CONCLUSIONS

Although streptozocin is a safe, streptozocin-induced renal dysfunction is a dilemma in streptozocin responders. Streptozocin may benefit patients with gastroenteropancreatic neuroendocrine tumors, especially those with a good performance status; however, in some cases, planned streptozocin withdrawal or switching to other drugs should be considered.

Recurrence-Free Survival and Disease-Specific Survival in Patients with Pancreatic Neuroendocrine Neoplasms: A Single-Center Retrospective Study of 413 Patients

INTRODUCTION

The prognosis and impact of different prognostic factors in pancreatic neuroendocrine neoplasms (pNEN) remain controversial.

AIM

To investigate prognostic factors for recurrence-free survival and disease-specific survival in patients with pNEN, divided into three groups: patients undergoing surveillance (tumor size < 2 cm, group 1), patients followed after curative-intended surgery (group 2), and patients with unresectable disease or residual tumors after resection (group 3).

METHOD

A single-center retrospective study including consecutive patients over a 20-year period. Multivariate Cox regression analyses were performed to identify risk factors.

RESULTS

413 patients were included, with a mean (SD) age of 62 ± 14 years. In group 1 (n = 51), median (IQR) follow-up was 29 (21-34) months, and tumor size was 1.0 (0.8-1.4) cm. One progressed and had a tumor resection. In group 2 (n = 165), follow-up 59 (31-102) months, median tumor size 2 (1.2-3.4) cm, median Ki-67 index 5 (3-10)%, the 5-year recurrence rate was 21%. Tumor size (p < 0.001), Ki-67 index (p = 0.02), and location in the pancreatic head (p < 0.001) were independent risk factors. In group 3 (n = 197), follow-up 19 (6-46) months, median tumor size 4.2 (2.6-7.0) cm, Ki-67 index 17 (9-64)%, the median disease-specific survival was 22 (6-75) months-99 in NET G1; 54 in NET G2; 14 in NET G3; and 6 months in neuroendocrine carcinomas (NEC). Age (p = 0.029), plasma chromogranin A (p = 0.014), and proliferation, expressed by grade (p = 0.001) and Ki-67 index (p < 0.001), were risk factors.

CONCLUSION

Growth in pNET < 2 cm requiring surgery was observed in 1/51. Tumor size, Ki-67 index, and location in the head were prognostic factors for disease recurrence, while age, plasma chromogranin A, and proliferation predicted mortality in patients with unresectable disease or residual tumors after resection.

Predictive Factors of Response to Streptozotocin in Neuroendocrine Pancreatic Neoplasms

Pancreatic neuroendocrine neoplasms (Pan-NENs) may exhibit a heterogeneous clinical course, ranging from indolent to progressive/metastatic behavior. In the latter scenario, streptozocin (STZ) is considered the cornerstone of systemic treatment; however, response to STZ-based chemotherapy may vary among individuals. In this narrative review, we aimed to identify the predictive factors of response to STZ in advanced Pan-NENs. We performed an extensive search in international online databases for published studies and ongoing clinical trials evaluating STZ in Pan-NENs. We found 11 pertinent studies evaluating 17 patient-, tumor-, or treatment-related factors. Age, CgA blood levels, tumor grade, Ki-67% index, anatomical location of the primary tumor, tumor stage, site of metastasis origin, liver tumor burden, extrahepatic spread, functional status, O6-methylguanine-methyltransferase (MGMT) status, line of therapy, and response to previous treatments were all statistically associated with radiological response and/or survival. The identified predictors may help clinicians make appropriate treatment decisions, in this way improving clinical outcomes in patients with advanced Pan-NENs.

European Neuroendocrine Tumour Society (ENETS) 2023 guidance paper for nonfunctioning pancreatic neuroendocrine tumours

This ENETS guidance paper for well-differentiated nonfunctioning pancreatic neuroendocrine tumours (NF-Pan-NET) has been developed by a multidisciplinary working group, and provides up-to-date and practical advice on the management of these tumours. Using the extensive experience of centres treating patients with NF-Pan-NEN, the authors of this guidance paper discuss 10 troublesome questions in everyday clinical practice. Our many years of experience in this field are still being verified in the light of the results of new clinical, which set new ways of proceeding in NEN. The treatment of NF-Pan-NEN still requires a decision of a multidisciplinary team of specialists in the field of neuroendocrine neoplasms.

Analyses of sex-based clinicopathological differences among patients with gastrointestinal neuroendocrine neoplasms in Europe

BACKGROUND

Previous studies have found variations in cancer types, tumor progression, and disease outcomes between men and women. However, there is limited knowledge of the effect of sex on gastrointestinal neuroendocrine neoplasms (GI-NENs).

METHODS

We identified 1354 patients with GI-NEN from the IQVIA's Oncology Dynamics database. Patients were derived from four European countries (Germany, France, the United Kingdom (UK), Spain). Clinical and tumor related characteristics including patients' age, tumor stage, tumor grading and differentiation, frequency and sites of metastases, as well as co-morbidities were analyzed as a function of patients´ sex.

RESULTS

Among the 1354 included patients, 626 were female and 728 were male. The median age was similar between both groups (w: 65.6 years, SD: 12.1 vs. m: 64.7 years; SD: 11.9; p = 0.452). UK was the country with the most patients, however, there was no differences in the sex ratio between the different countries. Among documented co-morbidities, asthma was more often diagnosed in women (7.7% vs. 3.7%), while COPD was more prevalent in men (12.1% vs. 5.8%). The ECOG performance states was comparable between females and males. Of note, the patients´ sex was not associated with tumor origin (e.g., pNET or siNET). Females were overrepresented among G1 tumors (22.4% vs. 16.8%), however, median proliferation rates according to Ki-67 were similar between both groups. In line, no differences in tumor stages was found and rates of metastases as well as the specific sites of metastases were similar between males and females. Finally, no differences in the applied tumor specific treatments between the both sexes became apparent.

CONCLUSION

Females were overrepresented among G1 tumors. No further sex-specific differences became apparent, highlighting that sex-related factors might play a rather subordinate role in the pathophysiology of GI-NENs. Such data may help to better understand the specific epidemiology of GI-NEN.

Clinical characteristics of 662 patients with pancreatic neuroendocrine tumors receiving antitumoral therapy

Pancreatic neuroendocrine neoplasia constitute an important subentity of the gastroenteropancreatic neuroendocrine neoplasms accounting for up to 15% of all neuroendocrine neoplasm. Prognosis and oncological behavior of pancreatic neuroendocrine tumors (pNETs) is extremely heterogenous and dependent on the specific tumor stage and differentiation. However, systematic data on the specific epidemiology of pNET are scarce. We identified 662 patients with pNET within the Oncology Dynamics database (IQVIA). Patients were derived from 4 European countries (Germany, France, UK, Spain), 3 Asian countries (Japan, China, South Korea) and 2 South American countries (Mexico and Brazil) and with regard to major patient and tumor related characteristics including patients' age, sex, tumor stage, tumor grading, and differentiation. The mean age of the study cohort was 62 years (SD 12 years) with 53.9.1% of all patients being male. The majority of patients had an Eastern co-operative of Oncology Group 1 performance status (63.3%). The most common Union international contre le cancer tumor stage was stage IV (85%) with liver metastases (89.0%) representing the most common site of extra-pancreatic tumor manifestation. The majority of all patients displayed well or moderate tumor differentiation (9.6% of patients had a Ki-67 expression below 2%. 67.6% of pNET patients had a Ki-67 expression between 2 and 20% and 22.8% of patients showed an expression above 20%). At time point of diagnoses, 93.1% of patients were classified as inoperable. Of note, 93.9 % of patients received systemic anti-tumoral therapy in palliative intention, while treatment was administered in 1.4 % of cases in neoadjuvant and in 4.7% of cases in in an adjuvant setting. Biological therapy was applied to 39.4% of patients, followed by targeted therapies (31.4%) and chemotherapy. Pancreatic neuroendocrine neoplasia are diagnosed in advanced tumor stages, globally. Systemic treatment was the most commonly used treatment modality. Such data may help to better understand the specific epidemiology of pNET worldwide.