Endocrine Abstracts

Background and aim: Neuroendocrine neoplasms (NEN) show increasing incidence and varying biology, but epidemiological and clinical data for other than gastroenteropancreatic (GEP) and thoracic NEN are scattered. Furthermore the best therapeutic approach in NEN arising in uncommon sites is still debated. Aim of this study is to assess the epidemiological and clinical features of NEN arising in uncommon sites in a monocentric series of a referral center.

Materials and methods: Epidemiological and clinical data of 182 patients with histologically confirmed NEN, referred at the Federico II NET Center of Naples, from 2002 to 2018, with newly diagnosed, sporadic and histologically confirmed NEN were retrospectively reviewed. NEN arising in uncommon sites were selected, while GEP and thoracic NEN, as well as pheocromocitoma, paraganglioma and medullary thyroid cancer were excluded.

Results: NEN arising in uncommon sites were diagnosed in 11 patients (6%), 6 males, 5 females, mean age 66 years (range 48–86). Median age at diagnosis was 64 years (range 48–85). Uncommon primary sites were: skin 4 (37%), rhinopharynx 2 (18%), bladder 1 (9%), breast 1 (9%), prostate 1 (9%), ovary 1 (9%), vagina 1 (9%). Clinical presentation is not specific and diagnosis was confirmed by anatomopathological examination. Mean Ki67 index, available in 8 patients, was 64% (range 5–80). Primary tumor was surgically resected in all patients, locally advanced in 5 (45%) and distant metastases occurred in 3 patients (27%), with primary located in bladder, rhinopharynx and prostate. Five (45%) patients underwent radiotherapy, 3 (27%) received therapy with somatostatin analogs (SSA), 1 (9%) platinum-based chemotherapy, 1 (9%) both SSA and platinum chemotherapy, 1 (9%) temozolomide. Median progression free survival (PFS) was 34 months ±13.2 (CI 95% 8–60). Median overall survival (OS) was 36 months (CI 95% 5–66). Seven (64%) patients were died at the time of the last follow-up, 5 of them due to disease related causes.

Conclusions: NEN arising in uncommon sites occur in older ages and often show an aggressive biological behavior, with high ki67 index. Surgery is the most common therapeutic approach, followed by radiotherapy. Low PFS and OS highlight the need of adequate therapeutic approach and identification of risk and prognostic factors.