Endocrine Abstracts

Objective: The prevalence of metastatic bone disease in patients with neuroendocrine tumours (NETs) and their response to first line treatment with biphosphonates.

Methods: We studied 271 patients (141 females) with NETs: 54 gastric, nine duodenal, 102 pancreatic, 29 small intestine, 29 appendix, 14 colon, 15 lung, one thymic, 20 unknown primary and ten elsewhere. Since September 2012 all patients with NETs and bone metastases were recruited to receive 4 mg of zoledronic acid monthly for two consecutive years. They were all followed-up by biochemical parameters and bone scan.

Results: In the whole cohort 13 (7.6%) patients had bone metastases. The prevalence of bone disease was 4.9% in pancreatic (five patients), 3.4% in small intestine (one patient), 7.1% in colon (one patient), 20% in lung (three patients), 100% in thymic NETs (one patient), and 10% in NETs with unknown primary NET (two patients). Two hundred 50 patients had sporadic NETS and 21 in the context of MEN1 and VHL; only one patient with MEN1 (4.8%) had bone disease. Ten patients were recruited in the treatment arm, three with lung (one completed 1 year of follow-up with improvement), three with pancreatic (one died after the 1st month of treatment), one with thymic (died before the 6-month evaluation) and one with sigmoid NET and two with unknown primary lesion (one died before a 6-month evaluation and the other had deterioration).

Conclusion: Approximately 4.2% of patients with NETs present bone disease. Our preliminary results show a 50% of positive response after treatment with biphosphonates in patients who remain alive during treatment.