Surgery/Intervention of neuroendocrine tumors
Neuroendocrine intestinal carcinoma. Click to enlarge the image.
The goal of a curative resection is complete removal of all of the diseased tissue. However, the tumor is often so advanced at the time of diagnosis that radical surgery is not possible. In these cases, some patients will benefit from a palliative resection or de-bulking operation, where most of the tumor tissue is removed. Debulking surgery is not recommended in poorly differentiated carcinomas.
Primary treatment for a tumor in the ileum is an intestinal resection, often with resection of a larger or smaller part of the intestinal mesentery. These tumors are often surrounded by a large fibrotic process. The tumor should be removed radically, if possible. It may be necessary to remove more of the intestines than the primary tumor, as removal of mesentery will involve blood circulation to more of the intestines than the tumor-bearing part.
It is estimated that a neuroendocrine carcinoma in the appendix is found in about 1 in 300 appendectomies. If the tumors are greater than >2 cm, or is located at the basis of the appendix or infiltrates the mesoappendix, it is recommended to perform a right-sided hemicolectomy.
The surgical treatment is, in principle, the same as for rectal tumors. The size and localization determines whether a resection can be performed with a primary bowel anastomosis, or if a rectum amputation with permanent sigmoideostomy must be performed.
Depending on the size and localization, different surgical approaches are chosen, from a simple resection of the intestinal wall, to a large operation including both the stomach and pancreas.
Treatment depends on the type of tumor, size, and localization. Generally, tumors lying on the surface of the organ may be resected locally or by nucleation.
The risk of complications for this type of treatment is usually relatively small. However, such local treatment cannot usually be carried out.
If the tumor is located in the body or the caudal area of the pancreas, a distal pancreas resection should be considered. If the tumor is located in the head area, the possibility of performing Whipple's operation (pancreatico-duodenectomy) is assessed. A distal pancreas resection can, in some cases, be carried out laparascopically in departments specializing in this type of surgery. Whipple's operation is a comprehensive operation with significant risk of complications.
Operation methods vary based on size and localization. Most often, treatment will involve wedge resections, a segment resection, or resection of an entire lung flap. Normal lung tissue is conserved as much as possible. Laser treatment is only an alternative for very small tumors, or when other types of procedures are contraindicated.
The surgical approach depends on the localization of the tumor(s). The operative method is a liver resection of some form, either local resections or more comprehensive resections in parts of the liver. Surgical treatment is evaluated against embolization or radiofrequency ablation. A liver resection is mainly recommended if the tumor can be completely removed. Palliative operations (de-bulking procedure) are only recommended if > 90% of the tumor tissue can be removed. It is then evaluated whether the rest of the tumor can be treated with embolization or ablation, possibly drug therapy.
For small tumors, it is recommended to monitor the patient's status over some time before choosing the operation. This is because these tumors develop very differently, from very slowly to rapidly giving rise to massive, diffuse spreading.
A liver transplantation may be an alternative for patients who, after surgical removal of the primary tumor, solely have liver metastasis which progresses despite medical treatment (8).
Radiofrequency ablation is carried out by inserting electrodes into the tumor with the help of ultrasound. Electricity is use to heat the tumor to about 100°C, which destroys the tumor cells. This can be performed as an open operation, laparascopy, or as a percutaneous procedure with the patient under general anesthesia.
There are limitations for when the method can be used. The tumors should not be greater than 4 cm in diameter. This method can be used on tumors in the liver where liver surgery is technically difficult.