Treatment patterns of gastrointestinal neuroendocrine tumors (NET).

Abstract

387 Background: NET comprise a broad set of rare tumors. Almost 2/3 arise in the gastrointestinal (GI) tract. NCCN guidelines for unresectable GI NET recommend somatostatin analogues (SSA) first, however, guidelines do not recommend a particular sequence for remaining therapies. Our objective is to describe real world treatment patterns of GI NET. Methods: This retrospective study combined 2 claims databases to examine newly pharmacologically treated patients using tabular and graphical techniques. Treatments included SSA, cytotoxic chemotherapy (CC), targeted therapy (TT), interferon (IF) and combinations. Patients ≥ 18 years, with ≥ 1 inpatient or ≥ 2 outpatient claims for GI NET who received pharmacologic treatment from 7/1/09-6/30/14 were identified. A 6 month clean period prior to first treatment ensured patients were newly treated. Patients were followed until end of enrollment. Results: We identified 2,258 newly treated GI NET patients. 59.6% started first line therapy with SSA monotherapy, 33.3% CC, 3.6% TT, and 0.5% IF. The remainder received combination therapies. Mean follow up was 576 days. Mean duration of first line therapy was 361 days for all newly treated patients (449 SSA, 215 CC, 267 TT). 58.9% of patients had no subsequent pharmarcological treatment after discontinuation of first line therapy.The most common second line was combination therapy with SSA (i.e., CC or TT added). In patients who did not begin with SSA, most received SSA as second line. In graphical pattern analysis, there was no clear pattern visible after first line therapy. Conclusions: More than 1/2 of pharmacologically treated patients began treatment with SSA and 1/3 with CC, with duration of use > 1 year and just over 6 months, respectively. We found treatment patterns after first line were unclear, and more than 1/2 of patients had no subsequent pharmacological treatments after discontinuing first line therapy. It is unclear whether there is underutilization of the pharmacological therapy or this is due to stable disease status after alternative non-pharmacological treatment. Future studies directed at understanding treatment patterns using patient medical records are warranted. As new treatments emerge, reassessment of treatment patterns may be needed.