Incidence of brain metastases (BMs) and outcomes in patients (pts) with extrapulmonary neuroendocrine neoplasms (EP-NENs).

Introduction: The incidence, management and outcomes of pts with EPNENs and BMs are unclear. Aim(s): To investigate outcomes in pts with EPNENs ± BMs. Materials and methods: A retrospective study of consecutivepts with EP-NENs and BMs treated at a single ENETS CoE was performed.Median (med) overall survival (OS)/survival from BM diagnosis were estimated(Kaplan Meier). Results: Between Aug 04-Feb 20, 730 pts with an EP-NENdiagnosis were identified: med age 64 yrs (15-90); 56% male, 67% hadadvanced disease (ADVD). In pts with ADVD, the primary NEN site were:small bowel 42%, pancreas 22%, unknown 14%, large bowel 10%, other 5%,stomach 4% and appendix <1%; 37%, 30% and 30% pts had grade (G)1, 2and 3 EP-NENs respectively (no grading 3%). Med OS for pts with ADVD G1,2 and 3 EP-NENs without BMs were 95.8 (95% C.I 77.0-177.1), 61.7 (95% C.I50.1-124.4) and 11.3 (95% C.I 9.3-14.4) months (mo) respectively. 17 pts(2.3%) developed BMs; 2 at initial diagnosis, 15 metachronously; 5 pts (29%)had a solitary BM, 12 (71%) had multiple BMs. The primary sites of originwere: unknown 41%, oesophagus 18%, pancreas 17%, small bowel 12%,cervix 6% and bladder 6%; 6%, 24% and 70% had G1, G2 and G3 EP-NENsrespectively. Most common presenting symptoms of pts with BMs were limbweakness and cognitive impairment. Pts with BMs received high dose steroidsand best supportive care (35%), whole brain radiotherapy with steroids (29%),surgery (18%) and localised radiotherapy (6%). Med OS for pts with G1+2 EPNENs and BMs was not reached. Med OS in pts with G3 EP-NENs and BMswas 9.0 mo (95% CI 6.0-12.1); med survival from BM diagnosis was 2.0 mo(95% CI 0.0-4.4). Conclusion: BMs in pts with EP-NENs are rare,predominant in G3 NENs, and have a poor prognosis. Improved therapeuticoptions are needed.