Incidence and natural history of bone metastases in neuroendocrine tumors.

Abstract

340 Background: Bone metastases (BM) occur in carcinoids and other neuroendocrine tumors (NET), however, a comparative analysis of the incidence and natural history of BM across different NET subtypes has not been performed. We retrospectively characterized BM incidence, complications, and management across five subtypes: carcinoid/unknown primary (CARC), pancreatic NET (PNET), pheochromocytomas/paragangliomas (PHEO), adrenal cortical carcinoma (ACC) and high grade NET (HGNET) using data collected in the context of the NCCN NET Outcomes Database. Methods: 296 NET patients (pts) presenting at UCSF from 2004 to 2007 were retrospectively identified. Eligibility criteria included presentation on or after Jan 1, 2004, continued management at UCSF within one year of consultation, age over 18, and pathological confirmation of an eligible NET subtype. BM identified radiographically and/or pathologically, and classified as symptomatic (pain, pathologic fracture, or spinal cord compression) or asymptomatic. BM treatments (tx) included radiation, surgery, bisphosphonate and/or denosumab. Results: BM identified in 36/296 (12%): 29% pts with HGNET (5/17), 10% pts with CARC (12/121), 7.4% pts with PNET (6/81), 17% pt with PHEO (11/66), 18% pt with ACC (2/11). BM occurred in 21 men/15 women; median age 54. 30/36 (83%) had stage IV disease at diagnosis (dx); 69% had BM at dx. 69% pts were eventually symptomatic: bone pain (24/25, 96%), cord compression (3/25, 12%) and/or pathologic fracture (6/25, 24%); 8/25 (32%) had more than one symptom from BM. Median survival from BM: 28 mo (21.1 mo if symptomatic; 34.3 mo if asymptomatic). Overall, 81% (29/36) pt received tx for BM: 53% XRT (19/36), 25% surgery (9/36), 39% bisphosphonate (14/36), and/or 11% denosumab (4/36). Conclusions: 12% of pts with NET in this database developed BM. Most pts with BM experienced pain. Serious complications such as cord compression and/or pathological fracture occurred in 36% (9/25) suggesting that bisphosphonate and/or denosumab tx may be of value in these patients. Accrual to the database is ongoing.