International Survey of Clinical Practice Exploring Use of Platinum-Etoposide Chemotherapy for Extra-Pulmonary High Grade Neuroendocrine Carcinoma (EP-G3-NEC)

Introduction: Platinum-etoposide (PE) chemotherapy (CH) is a globallyestablished combination for EP-G3-NEC; the optimal schedule has not beenestablished. Aim(s): The aim was to explore which PE CH schedules are inuse across centres, to assess consistency in clinical practice. Materials andmethods: An international survey was designed, and completed by clinicianswith an expertise in the field. Results: Seventy-five replies were received(June-Nov’17) from medical oncologists, (n=53; 70.7%), radiation oncologists(12; 16.0%), gastroenterologists (8; 10.7%) and endocrinologists (2; 2.7%);most frequent countries of practice: United Kingdom (25; 33.3%) and Spain(13; 17.3%). Most physicians (40; 53.3%) had >10 years’ NET experience; 32(43.20%) were working in ENETS Centres of Excellence. A minority (13;17.6%) did not take Ki67 or morphology (9; 12.0%) into consideration forselection of CH regimen. Most respondents (72; 96.0%) selected PE CH asfirst-line treatment for EP-G3-NEC; with variable impact of poor-differentiationand/or Ki67>55%. There was also variability regarding schedules used:cisplatin-based (37/71; 52.1%), carboplatin-based (34/71; 47.9%); intravenousetoposide (64/71; 90.1%), oral etoposide (7/71; 9.9%). CH was usuallyadministered up to a maximum of 6 cycles (58; 79.5%). Choice of second-lineCH depended on time to progression on PE-based first-line: if >6 months, rechallengewith PE was the preferred choice (34; 45.9%); if <6 months,alternative combinations such as fluoropyrimidine/irinotecan (21; 29.2%) ortemozolomide/capecitabine (22; 30.6%) were used. Conclusion: Significantvariation in PE regimen employed exists. Standardising clinical practice wouldfacilitate clinical trial development.