Carcinoid tumors are slow-growing neuroendocrine tumors that originate from cells of the neuroendocrine system. Most patients will not show obvious symptoms in life and are usually discovered accidentally during surgery for other reasons. However, once carcinoid syndrome develops, it can cause a variety of symptoms, including heart lesions.
About 10% of carcinoid tumors secrete too many hormones, especially serotonin, which can affect heart health.
Carcinoid tumors are most commonly found in the small intestine, especially the ileum, but are also found in the cecum and rectum. These tumors grow slowly relative to other malignancies, so many patients do not experience any discomfort in the early stages of the disease. However, when these tumors begin to metastasize to other organs, especially the liver, the development of carcinoid syndrome may be observed, with complications from cardiac disease occurring in 49% of patients.
Symptoms of carcinoid syndrome include facial flushing, diarrhea, and heart valve disease, all of which are associated with secretions from the tumor.
Carcinoid syndrome is a set of symptoms caused by tumors releasing too much serotonin and other biologically active substances. These symptoms include skin flushing, diarrhea, bronchoconstriction, and right ventricular valve disease. Serotonin promotes the proliferation of heart muscle cells, which can cause tricuspid valve disease, a direct link between carcinoid syndrome and heart disease.
Although most patients will not be affected by carcinoid tumors during their lifetime, a small number of patients will develop carcinoid syndrome, usually because the tumors increase in number or metastasize. Certain gastric gland carcinoid tumors are more likely to occur in the presence of low stomach acid, which is associated with chronic conditions such as hashish thyroiditis or pernicious anemia.
About 1 in 5 men will develop a syndrome caused by carcinoid tumors, and 50% of these will involve heart problems.
For carcinoid tumors, surgery is the primary treatment. If the tumor has metastasized to the liver, which is generally considered incurable, treatment with radiopharmaceuticals can be used to suppress tumor growth and prolong the patient's life. Chemotherapy is generally ineffective against carcinoid tumors and is generally not recommended.
Patient symptom management is also critical, as somatostatin analogs (Octreotide or Lanreotide) can help reduce endocrine secretion activity and have a certain inhibitory effect on tumors.
As research into carcinoid tumors and related cardiac lesions continues, the medical community's understanding and management of these symptoms will continue to improve. In addition, how to apply this knowledge to clinical practice to help more patients obtain early diagnosis and timely treatment will be an important direction in the future.
When we think about why carcinoid syndrome affects a small number of patients but is strongly linked to heart disease, should we reexamine our attitudes toward and treatment of this disease?