NEUROENDOCRINE TUMOURS: MANAGEMENT
Treatment should always aim to cure if possible but as most patients present with local or distant metastases this is often not possible. Under such circumstances, the goals of treatment are to control symptoms and halt or reverse tumour growth for as long as possible. For many patients, this is achievable for several years even in the presence of metastases because of the indolent nature of many NETs. Treatment choice is influenced by histological grade, stage, symptoms and radionuclide (Octreoscan®) uptake. Importantly, treatment decisions should be undertaken by a multidisciplinary team with experience in managing NETs (Figure 32.1).
This should be undertaken for patients with potentially curative disease. Increasingly, surgery is also considered in patients with liver metastases confined to one lobe, or in bilobar disease and a single dominant lesion causing symptoms.
Somatostatin analogues form the mainstay of treatment for most patients with NETs. Immediate-release octreotide has now been largely superseded by long-acting depot preparations (octreotide LAR or lanreotide autogel), given every 3–4 weeks. These preparations lead to significant symptomatic improvement in patients with carcinoid syndrome or functional pancreatic NETs, and reduce the time to tumour progression in symptomatic or asymptomatic tumours. Two new drug therapies, sunitinib (a tyrosine kinase inhibitor) and everolimus (an mTOR pathway inhibitor), have recently become licenced for pancreatic NETs.
Chemotherapy is not widely used in the management of NETs but does have a role in higher grade NETs, especially those of pancreatic origin.
Radiofrequency ablation and transarterial hepatic embolisation can lead to symptomatic improvements in patients with liver predominant disease.
Carcinoid heart disease
About 20–30% of patients with carcinoid syndrome develop carcinoid heart disease. This typically affects the right-sided heart valves (tricuspid more commonly than pulmonary) and is best diagnosed by echocardiography. Symptomatic relief can be obtained with diuretic therapy, but valve replacement surgery is often needed as definitive treatment.
This is highly variable and dependent on a number of factors including histological grade, stage, primary tumour site and co-morbidities. It is important to recognise that patients with well-differentiated, low grade tumours can live for many years resence of metastatic disease, hence quality of life is very important treatment goal.