Endocrine Abstracts

Background: The prevalence of neuroendocrine neoplasms (NENs) among younger adults is low; clinical management mirrors that in older cohorts. This study aimed to review presentation, disease trajectory and survival outcomes according to treatment in patients aged 18-40 years (y).

Methods: An electronic database was searched (retrospectively) for patients with NENs (18-40y) (cut-off May 2023). Patients with VHL, tuberous sclerosis, familial adenomatous polyposis or MEN-1/2 were excluded. Patterns of presentation were analysed, including disease primary and tumour grade. Follow-up/survival times were calculated.

Results: 68 patient files were searched (2013-2023); 52 were eligible (median age: 34y (21-40), males: n=27 (52%). Primary site: lung n=22 (42%) (typical lung carcinoid n=21), gastrointestinal (GI) n=20 (38%), pancreas n=8 (15%), biliary n=2 (4%)). Fifteen (28.8%) patients presented with Grade 1 (G1) NETs, 7 (13.5%) with G2, 8 (15.4%) with G3; 2 well-differentiated G3 NET, 6 with NECs, & 21 (40.1%) with typical carcinoid, 1 (1.9%) with atypical carcinoid. Thirty-two patients (61.5%) underwent surgery; lung n=18, jejuno-ileal n=5, pancreas n=3, colon & rectum n=2 each, duodenum & gall bladder n=1 each; 3 cases (5.8%) with palliative intent. In patients undergoing curative resection (n=29), median (m) disease-free survival was not reached (NR); 1 (4%) had relapsed disease (colon NEN) & 2 (6.3%) had post-operative synchronous liver metastases. Twenty-one patients (40%) had metastatic disease; 13 received an SSA (lanreotide/octreotide); mPFS was 21.4 months (mo) (all groups). Six patients had PRRT; mPFS NR. Fourteen patients underwent chemotherapy; 11 for metastatic disease and 2 perioperatively (one patient excluded due to lack of data). mPFS with 1st line chemotherapy was 5.13m (n=11) (mPFS with 2nd line chemotherapy was 1.5m (n=5)). There were 10 deaths (19.2%): mOS 38.1m; gastric type 2: 30% (G3 NET n=1, NEC n=2), pancreas: 30% (G2 NET n=3), gall bladder: 20% (G3 NET n=1, NEC n=1), gastric type 3: 10% (NEC n=1), duodenum: 10% (NEC n=1)).

Conclusions: In this cohort of younger adults, the most common primary site was lung. The majority had surgery with a low recurrence rate. The mPFS on SSAs was favourable compared to historical values. Patients undergoing chemotherapy had a poor prognosis.