From the Guidelines
Large intestinal carcinoid tumors typically present with symptoms such as abdominal pain, changes in bowel habits, blood in stool, unexplained weight loss, and fatigue, rather than carcinoid syndrome, which is rare in these cases due to liver metabolism of the hormones produced by the tumor. The symptoms of large intestinal carcinoid tumors can vary depending on the location of the tumor within the large intestine. According to 1, approximately two-thirds of carcinoid tumors arise in the gastrointestinal tract, with sites of origin including the stomach, small intestine, appendix, and rectum.
Some patients may experience a feeling of incomplete evacuation after bowel movements. Unlike small intestinal carcinoids, large intestinal carcinoids rarely cause carcinoid syndrome (flushing, diarrhea, wheezing) because the hormones they produce are metabolized by the liver before reaching systemic circulation, as noted in 1 and 1. Right-sided tumors may grow larger before causing symptoms, while left-sided tumors may cause earlier obstructive symptoms due to the narrower lumen.
The prognosis for patients with carcinoid tumors varies according to stage at diagnosis, histologic classification, and primary tumor site, as stated in 1. Some patients remain asymptomatic, with tumors discovered incidentally during screening colonoscopies. The symptoms typically develop gradually over time as the tumor grows. If metastasis occurs, particularly to the liver, patients may develop carcinoid syndrome or symptoms related to the affected organs, as mentioned in 1 and 1. Early detection through regular colorectal cancer screening is important as symptoms often appear only in advanced disease.
Key symptoms to look out for include:
- Abdominal pain
- Changes in bowel habits (constipation or diarrhea)
- Blood in stool
- Unexplained weight loss
- Fatigue
- Feeling of incomplete evacuation after bowel movements It is essential to note that carcinoid syndrome, characterized by flushing, diarrhea, and wheezing, is rare in large intestinal carcinoid tumors unless liver metastases are present, as highlighted in 1 and 1.
From the Research
Symptoms of Large Intestinal Carcinoid
- The symptoms of large intestinal carcinoid can vary, but common symptoms include:
- Carcinoid syndrome, which can occur in patients with large intestinal carcinoid, is characterized by:
- Other symptoms that may be present in patients with carcinoid syndrome include:
Biochemical Markers
- Serum chromogranin A is a nonspecific biochemical tumor marker for carcinoid tumors 2
- Increased urinary excretion of 5-hydroxy indole acetic acid (5-HIAA) is a specific marker for the carcinoid syndrome 2, 5
Localization and Treatment
- Localizing studies for carcinoid tumors/syndrome include:
- Transabdominal ultrasonography (US) 2
- Endoscopy 2
- Endoscopic US 2
- Videocapsule endoscopy 2
- Computerized tomography 2
- Magnetic resonance imaging 2
- Selective abdominal angiography 2
- 111In-pentetreotide scintigraphy (and intraoperative radionuclide probe) 2
- 123I (131I)-metaiodobenzylguanidine (MIBG) scintigraphy 2
- Bone scintigraphy 2
- 11C-5-HT positron emission tomography (PET) 2
- Therapies for carcinoid tumors/syndrome include:
- Surgery 2, 5
- Somatostatin analogs 2, 3, 4
- Interferon-alpha 2
- Radiotherapy 2
- Liver dearterialization 2
- Liver (chemo, or radio)-embolization 2
- Alcohol sclerotherapy of liver metastases 2
- Radiofrequency ablation of liver metastases 2
- Cryosurgery of liver metastases 2
- Occasionally liver transplantation 2
- Radiotherapy-coupled somatostatin analogs 2
- 131I-MIBG 2
- Occasionally chemotherapy 2