Endocrine Abstracts

Background: Metastatic pheochromocytomas (PCs) and paragangliomas (PGLs) are rare neuroendocrine neoplasms with a <1:10⁶ incidence, defined by the presence of metastatic disease besides recurrent or locally invasive disease.

Aim: Retrospective analysis of clinical, biochemical/hormonal, imaging, genetic and histopathological features of patients with malignant PCs/PGLs diagnosed over 15 years.

Results: Thirteen patients (aged 49.5±15.5 years old) with either metastatic PCs (n=6) or PGLs (n=6) were collected; one had both PCs and PGLs. The mean follow-up period was 6.38 years (range: 1–14 years). Almost half of the patients presented with synchronous metastases mostly in lymph nodes (cervical and abdominal); the remaining developed metastases after a mean follow-up of 4 years (range 2–10 years). Seventy per cent of the patients had functional neoplasms; 6 (46%) had concomitant normetanephrine and metanephrine secretion, one only dopamine and 2 only normetanephrine secretion. Out of 6 patients tested genetically, one had SDHB mutation and another SDHD. The mean Ki-67% proliferative index of the primary and metastatic sites were 11±3.8% and 44±7% respectively. Eight patients (62%) underwent surgical resection of the primary tumour or multiple surgical interventions. Two developed stable disease (SD) without further treatment whereas the remaining progressed (PD) and received additional therapeutic modalities. Four patients had treatment with radiopeptides (PRRTs) (2 with 17Lu-DOTATE and 2 with 131I-MIBG) either as monotherapy or after surgery; two exhibited SD. Four patients received chemotherapy, either as monotherapy or after surgery but all developed PD. Two patients had localised radiotherapy, the first as monotherapy and the second after chemotherapy and they both progressed. Two patients (15%), deceased during the follow-up period: the first one year after the detection of metastases and the second 8 months after initial diagnosis.

Conclusions: Metastatic PGLs and PCs are rare tumours that can achieve prolonged survival. In our small series, it seems that PRRTs could be a promising treatment for advanced and/or non operable PCs/PGLs. However, allthese patients require multiple therapeutic modalities either local or systemic best dealt in a multidisciplinary setting.