Carcinoid syndrome usually takes place in patients with an advanced stage of carcinoid tumors. Carcinoid tumor is a type of rare tumors that occur in the small intestine, appendix, and lung. Moreover, it may grow in other organs of the body like ovaries. According to recent data, 40% of neuroendocrine tumors patients develop carcinoid syndrome which is characterized by the following symptoms:
- Severe diarrhea
- Heart failure
These symptoms are usually attributed to the production of two key endogenous secreted by the tumor, serotonin, and kallikrein.
Several tests are used to screen and diagnose carcinoid tumors:
- Chromogranin A (CgA) test, which is a screening test. This screening test has the limitation of non-specificty to carcinoid tumors. Its level could be elevated by other diseases like pheochromocytoma, hypercortisolemia, hyperthyroidism, medullary thyroid cancer, hyperparathyroidism in addition to the stress level.
- 5-HIAA (5-Hydroxyindoleacetic Acid) test, which measures the level of 5-HIAA in urine for the last 24 hours. This test is a screening test. It was found that the type of food may affect the level of 5-HIAA. Based on that, patients that would like to conduct this test should avoid foods like bananas, walnuts, pineapple, tomatoes, eggplant, kiwi fruit and plums as it contains serotonin (5-HIAA’s precursor).
- Gallium-68 PET/CT DOTATATE scan is considered as one of the confirmatory tests. This test is used to detect both size and location of the tumor.
- Octreoscan: is another confirmatory test where labeled Octreotide is used to confirm the diagnosis.
Patients with Carcinoid tumors suffer from severe diarrhoea. Usually treating physicians prefer to use either Octreodite or Lanreotide injections to control diarrhea and flushing of patients. It was found that the quality of life for patients with Carcinoid tumors improves significantly with the usage of somatostatin analogues like (Octreodite or Lanreotide). In 2020, a new oral form of Octreotide was approved by FDA for the management of Acromegaly, but still not approved for carcinoid syndrome or neuroendocrine tumors.