Endocrine Abstracts

Olfactory neuroblastoma (ONB) is a rare neuroendocrine tumour arising within the sino-nasal cavity. It occurs world wide, affecting both sexes, all ages and all races with no underlying predilection having yet been identified. ONB exhibits a range of phenotypes from indolent to very aggressive, and up to 5% cases are associated with ectopic hormone secretion. Despite current gold-standard treatment of surgical resection (either endoscopic or craniofacial resection) followed by post op radiotherapy ± chemotherapy patients remain at lifelong risk of recurrence. Early stage disease has recurrence rates of up to 60%, and patients presenting with advanced (stage 4) or metastatic disease have a poor prognosis. At present very little is known about the molecular mechanisms underlying tumourigenesis in ONB. New disease biomarkers and treatments are therefore urgently needed.

Our multi-centre patient cohort (n=48) shows a wide age range at diagnosis and no clear difference between sex and race. The average age at presentation is 56 years, however stratification of our data reveals that patients presenting with intracranial disease are typically younger (48 years) as are patients who go on to develop metastatic disease (47 years). In our cohort all patients under 40 years presented with advanced disease (stage 3 or 4) and stage 4 disease was the most commonly diagnosed stage at presentation in all patients under 50 years. Stage 2 disease was most common in the 50–70 age group. Overall there was a 41% recurrence rate in our cohort, with multiple recurrences affecting 11%.

We summarise our patterns of recurrence, metastatic disease and outcomes related to patient age, stage and grade at presentation and treatment modalities used. We also highlight atypical features seen in some groups, and demonstrate altered immuno-histochemical profiles in some patient subgroups which may represent de-differentiation of the tumour to a more aggressive phenotype.