Refractory Carcinoid Syndrome in Small Intestine NET: What to Do After First-Line Treatment Fails
This protocol applies to patients with small intestine neuroendocrine tumour (Si-NET) presenting with carcinoid syndrome — characterised by diarrhoea and flushing — in whom first-line medical management did not achieve adequate symptom and biochemical control.
Clinical Scenario: Carcinoid Syndrome
Patients with Si-NET may present with carcinoid syndrome (CS) due to secretion of biologically active compounds such as serotonin and tachykinins, or may be discovered during surgery for intestinal obstruction or bleeding. Patients with CS follow a distinct management pathway from those with non-functioning Si-NET.
First-Line Therapy Did Not Meet Goals
Prior therapy for refractory CS included addition of telotristat ethyl (oral) to somatostatin analogue (SSA), SSA dose escalation or high-dose SSA, or addition of IFN-α. The therapeutic targets — reduction of diarrhoea and 5-HIAA levels — were not adequately achieved. This protocol defines the escalation step.
Next-Line Treatment Approach
In this setting, locoregional and ablative treatments — including debulking surgery — are considered among the early options for refractory carcinoid syndrome. Additional escalation strategies are available depending on disease extent and behaviour.
Full regimen, sequencing, and all treatment criteria are available in the complete structured protocol below.
References
DOI: 10.1111/jne.13423It is important to note that patients suffering from CS are treated differently from patients with non-functioning Si-NET.
Some patients present with specific symptoms of the carcinoid syndrome (CS) due to secretion of biologically active compounds such as serotonin and tachykinins or are discovered during surgery for intestinal obstruction or bleeding.
Locoregional and ablative treatments including debulking surgery, should be considered early for refractory CS (Recommendation B-3a).
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