Endocrine Abstracts

Introduction: European Neuroendocrine Tumour Society guidelines advocate the use of platinum-based chemotherapy in combination with Etoposide as first line chemotherapy in advanced GEP-NEC. Following this regime, 30% of digestive NEC and 60% of colorectal NEC showed a lack of benefit or evidence of disease progression. Available retrospective evidence is from small studies. Other studies have shown BMI relates to survival in NEN. This study aims at studying chemotherapy regimens used in England in the last 10 years for patients with GEP-NEC.

Methods: Patients with primary GEP-NEC diagnosed between 2012-2021 were extracted from NCRAS and divided into chemotherapy (group-1) or no chemotherapy (group-2). Kaplan Meier estimated overall survival (OS) was calculated by site, chemotherapy regimen and body mass index (BMI). Logistic regression was used to evaluate for significant factors associated with receiving chemotherapy.

Results: 2,636 patients with GEP-NEC were extracted. 38% received first-line chemotherapy. The most common site to recieve chemotherapy was pancreas (35.3%). 50.3% of patients in group-1 had performance status of 0 or 1. In total, 64 different regimens were used. The most common regimen was Cisplatin/Carboplatin+etoposide (66.1%). Carboplatin+5FU+Streptozocin was used in 3.4% of patients. OS in the chemo group was higher in the first 12 months (48.1% vs. 41.5%). Small intestinal NEC and caecal NEC receiving chemotherapy had the highest and lowest OS respectively (73.5% vs. 31.9%). Appendiceal and colonic NEC not receiving chemotherapy had highest and lowest OS respectively (87.6% vs. 21.6%). Patients who received Carboplatin+5FU+Streptozocin had higher OS compared to Cisplatin/Carboplatin+etoposide in all sites combined and in the colorectal NEC subgroup. Multivariable logistic regression showed routine diagnostic presentation (versus emergency presentation), younger age and advanced stage were more likely to receive chemotherapy. Small intestine and appendix NEC had lower rates of chemotherapy. No difference in OS of group-1 was shown between BMI groups.

Conclusion: Most patients with GEP-NEC do not receive chemotherapy. There is a large variation in chemotherapy regimens in GEP-NEC with Cisplatin/Carboplatin+etoposide being the most common regimen. Receiving chemotherapy is associated with younger age, advanced stage and elective diagnosis. BMI has no effect on OS of GEP-NEC.