Inclusion Criteria:

- Adults age 18 years or older at time of NET diagnosis.

- Diagnosis of GEP-NET or lung NET between 1/1/2019 and 12/31/2023, as evidenced by:

- medical record information on diagnoses and/or medications and/or treatments
and/or test results and/or clinical notes and/or procedures and/or encounters and/or tumor characteristics; and

- patient self-report of their diagnosis.

Exclusion Criteria:

- Any GEP-NET/Lung NET prior to 1/1/19, as evidenced by:

- Medical record information on diagnoses and/or medications and/or treatments and/or test results and/or clinical notes and/or procedures and/or encounters and/or
tumor characteristics; and

- patient self-report of their diagnosis.

- No evidence of NET treatment at the study site as evidenced by medical record information on provider encounters and / or patient is deceased per vital status.