In an individual cancer patient extensive genetic and phenotypic variation exists between and within tumor lesions. Tumour load in NET patients can be measured with fluorine-18-L-dihydroxyphenylalaninepositron emission tomography (18F-DOPA-PET) scan.

This aim of the study is to investigate heterogeneity between tumor lesions within patients with intestinal NET by determining the differences in tracer uptake measured on a 18F- DOPA-PET scan retrospectively.

In an individual cancer patient extensive genetic and phenotypic variation exists between and within tumor lesions. Tumour load in NET patients can be measured with fluorine-18-L-dihydroxyphenylalanine positron emission tomography (18F-DOPA-PET) scan.

This aim of the study is to investigate heterogeneity between tumor lesions within patients with intestinal NET by determining the differences in tracer uptake measured on a 18F- DOPA-PET scan in retrospect.

Inclusion Criteria:

• age ≥18 years
• diagnosis of intestinal NET diagnosed by a dedicated NET specialist
• more than one positive lesion on the 18F-DOPA-PET scan.
• available CT-scan within 6 months before or after the 18F-DOPA-PET-scan.

Exclusion Criteria:

• no clinical data available at the UMCG, besides the results of the DOPA PET scan.

We will select the 18F- DOPA-PET scans conducted in the UMCG of adult patients with a metastasized intestinal NET between February 2014 until November 2015. Only patients of whose clinical data are available within the UMCG are included.