This study aims to characterize current treatment patterns and clinical outcomes among newly diagnosed GEP-NET patients in the United States using open-source Longitudinal Prescription Claims (LRx) and Patient Centric Medical Claims (Dx) databases supplemented with mortality data.

Inclusion criteria:

1. Patients with ≥1 International Classification of Diseases Clinical Modification, 10th revision (ICD-10-CM) diagnosis code for GEP-NET between 01 January 2018 and 31 December 2025. The date of the first such claim will be defined as the diagnosis date.

2. Initiation of first-line (1L) systemic therapy (i.e., somatostatin analogs [SSAs], targeted therapy, peptide receptor radionuclide therapy [PRRT], chemotherapy) indicated for GEP-NET on or after the date of diagnosis. The date of treatment initiation will be defined as the index date.

3. Patients ≥18 years of age on the index date

4. Patients with ≥12 months (360 days) of continuous data availability (proxy for continuous health plan enrollment) prior to the index date, defined as:

   1. ≥1 medical and pharmacy claim >12 months prior to the index date; AND
   2. ≥1 medical and pharmacy claim within the first 6 months of the 12-month period prior to the index date; AND
   3. ≥1 medical and pharmacy claim during the last 6 months of the 12-month period prior to the index date; AND

5. Patients with ≥1 month (30 days) of continuous data availability (proxy for continuous health plan enrollment) following the index date, defined as:

   1. ≥ 1 pharmacy dispensing a GEP-NET treatment at any time during the post-index period, including the index date, reports data during the first month following the index date
   2. ≥ 1 provider prescribing a GEP-NET treatment at any time during the post-index period, including the index date, reports data during the first month following the index date

Exclusion criteria:

1. Patients with evidence of GEP-NET prior to the diagnosis date within the study period
2. Patients with evidence of GEP-NET treatment prior to the index date within the study period
3. Patients with missing or invalid age or sex
4. Patients with other primary malignancies during the 12-month pre-index period
5. Patients with invalid death date (i.e., death date ≤ index date)

Patients with evidence of a GEP-NET diagnosis between 01 January 2018 and 31 December 2025 and initiating a 1L treatment during this time period.