The management of neuroendocrine tumours of the gastrointestinal tract varies significantly on the location, type and extent of disease.
Insulinoma
Insulinoma is the most common neuroendocrine tumour of the pancreas. For small (< 2 cm) lesions, local surgical excision is usually curative. Larger lesions require partial pancreatectomy due to high risk of local recurrence.
Other Grade 1-2 GEP-NETs
Localised tumours should be managed with curative surgical excision. The technique depends on the location of the tumour; eg. for gastrinoma of the pancreatic head a pancreatoduodenectomy is performed. Rectal and appendiceal NETs can be locally excised safely, whereas those in other sites generally require a lymph node dissection.
Metastatic tumours are incurable and management involves:
- Control of hormonal symptoms
- Surgical excision of macroscopic disease should be undertaken where feasible, including partial liver resections. This removes a significant tumour burden and reduces symptoms related to hormone secretion
- Octreotide, a somatostatin analogue, binds to the somatostatin receptor which is frequently expressed by functional neuroendocrine tumours. This can be functionally imaged using an Somatostatin Receptor Scintigraphy scan but therapy should be attempted even when the scan is negative. Somatostatin inhibits the release of hormones from neuroendocrine cells and can significantly reduce the intensity of symptoms.
- Interferon has been used in the past.
- Patients without hormonal symptoms
- Slowing progression of disease
- Pancreatic neuroendocrine tumours may respond to systemic cytotoxic therapy.
- Radiotherapy may also be of use in pancreatic NETs although historically has been avoided; this has been challenged in recent studies
- Cytotoxic therapy is of minimal use in other neuroendocrine tumours of the gastrointestinal system
- Everolimus may slow progression of disease is a small number of patients
Poorly Differentiated Neuroendocrine Tumours
These tumours have a high mitotic count (typically > 20 per 10 HPF, or Ki-67 > 20%). They behave like small cell carcinoma of the lung, itself a poorly differentiated neuroendocrine tumour, and are treated with systemic cytotoxic chemotherapy that is usually platinum based. Survival is limited.
