Neuroendocrine Tumour (Carcinoids & NET)
Neuroendocrine cancers are rare cancers arising from the endocrine system, which forms a network of glands in the body. This wide network of glands produce a variety of hormones for proper body functions, and can also give rise to an extensive variety of cancers.
Neuroendocrine cancers produce hormones that may cause symptoms such as flush-ing of the skin, wheezing, diarrhoea and fainting spells. Those that do not produce hormones are also called the non-functioning tumours.
Carcinoid tumour is the old terminology for gastrointestinal and lung neuroendocrine tumours. Gastroenteropancreatic neuroendocrine tumours (GEP-NET) is a new termi-nology.
The common sites in the digestive tract are the appendix and small bowel. These tu-mours can also occur in the pancreas (PNET - pancreatic neuroendocrine tumour), bile ducts, gallbladder, duodenum, stomach, large intestine or rectum.
Neuroendocrine tumours are usually slow growing. They may be present for several years without causing harm to the body or giving rise to symptoms. However, a subset of neuroendocrine tumours is more aggressive and hence more likely to invade and damage surrounding vital organs or body structures.
The symptoms of a neuroendocrine tumour are dependent on the location in the body and on the types of hormone produced. For instance, small bowel neuroendocrine tu-mours may produce a hormone known as serotonin. Often, the liver clears the seroto-nin produced by the cancer and in such situations, the patients remain symptom free until the cancer has spread to the liver. Due to the silent nature of these cancers, they are not easy to diagnose in the early stages. Some cases are discovered incidentally through health screening or by chance during an operation for another condition.
Once the tumours spread to the liver, it causes a group of symptoms called carcinoid syndrome. The symptoms are the result of excess hormones in the body. Patients may have diarrhoea, flushing of the skin, wheezing and weight loss.
To diagnose this cancer, your doctors may order tests such as full blood count, liver function tests, blood serotonin, chromogranin A (CgA) and 5HIAA urine test. Scans and imaging studies to evaluate the cancer include ultrasound scan of the heart (echocardiogram), CT scan, magnetic resonance imaging (MRI), Gallium-68 Doctate scan and 18-FDG positron emission tomography scan (PET). Fine needle aspiration biopsy (FNAC) may be taken to confirm the diagnosis.
Biopsy samples allow your doctor to assess the cancer. This is an important step before the doctor recommends the most appropriate treatment for our patients. The grade of the cancer predicts the behaviour of the cancer. For instance, low grade predicts a slow growing tumour, while high grade predicts a faster growing tumour. The stage de-scribes the extent of the cancer growth, i.e. whether the cancer is within the organ of origin, or whether it has spread to the nearby lymph nodes or farther such as to the lung and liver.
Surgery is the mainstay of treatment. When the cancer is completely removed, “cure” is possible in a slow growing cancer, even when the cancer has spread to the liver. Op-eration on the liver (partial hepatectomy) can be performed safely only if there is limited cancer spread to the liver. If the cancer cannot be completely removed, debulking sur-gery to remove most of the cancer improves survival and relieves symptoms in some of these patients. Some of these cancers which have spread to other parts of the body but are symptom free, may be treated conservatively.
Other treatments for these cancers are chemotherapy, targeted therapy (molecular therapy), somatostatin analogues (Sandostatin), targeted radiotherapy; also known as peptide receptor radio-nuclear therapy (PRRT), hepatic artery embolization (TACE or TAE) and radiofrequency ablation (RFA). Your doctor may discuss these options and advise appropriate treatment.