Excision of GISTMedical editor Stephan Stoldt MD
Oslo University Hospital
Raphael Pollock, MD, PhD
MD Anderson Cancer Center
For localized intraabdominal or visceral sarcomas including GIST, operative treatment with complete resection of the tumor is the only curative modality and is indicated in all patients that seem medically fit to undergo the procedure.
Only in selected cases of localized GIST, especially in the rectum, where downstaging of the tumor is desirable in order to limit the extent of an operation, will neoadjuvant treatment with thyrosinase kinase inhibitors be instituted for a period ranging from 6-12 months.
Intraabdominal sarcomas can present with an intact serosal covering toward the peritoneal cavity, but in many instances this margin is nonexistent and the tumor has a naked intraperitoneal surface that greatly increases the risk of transperitoneal metastasis.
Tumor rupture, if not already present before operation, should be avoided by meticulous handling of these tumors. All peritoneal surfaces should be examined for potential metastasis.
The extent of resection of the gastrointestinal organ of origin is dependent on the size of the tumor base, its location and other anatomical and physiological aspects. Partial resections are most often sufficient to achieve negative tumor margins.
When surrounding organs have tight adherances to the tumor, an en bloc resection of these organs with the tumor should be performed. Only in selected cases should these patients be treated by laparoscopic procedures.
- The patient is free of macroscopic tumor tissue.
- Common laparotomy tray
- Self-retaining abdominal retractor, Bookwalter or similar
- Depending on the localization of the tumor: Ligasure, staple instruments (GIA, TA)
- Depending on the localization of the tumor in the GI-tract, preoperative colon emptying may be necessary.
- Antibiotic and thrombosis prophylaxes are given.
- Epidural catheter is inserted for pain treatment.
- A bladder catheter is installed unless the procedure is of very short duration.
- The patient is operated under sedation.
- The positioning of the patient depends on location of the incision.
The same oncological principles described in the resection of retroperitoneal sarcomas are applied.
- A generous midline incision is the preferred surgical approach.
- Occasionally, this incision is extended to either groin or as a thoracotomy for optimal exposure.
- The tumor must be excised with an intact pseudo-capsule in order to attain negative margins and avoid tumor spillage. This can only be achieved by careful dissection within normal tissue around all planes of the tumor.
- If necessary, involved and/or contiguous fixed organs must be removed en-bloc with the tumor. Violation of the tumor capsule undoubtedly leads to tumor cell spillage and this in turn translates to a high risk for relapse and reduced prognosis.
- Tumors localized in the right retroperitoneal space are often resected en-bloc with the right kidney, right adrenal gland, and right hemicolon. When in the left retroperitoneal space, tumors are often removed together with the left kidney, left adrenal gland, tail of the pancreas, spleen, and left hemicolon.
- In some cases, muscular structures that delimit the retroperitoneal space like the diafragm, psoas, iliacus, or transversus abdominis must be partially resected together with the tumor. In other cases, small bowel is fixed to the tumor and must also be partially removed.
A detailed operative description, including status of peritoneal surfaces, inadvertent intralesional dissection and tumor rupture must be reported in order to aid in risk-classification and indication for postoperative systemic treatment.
Complications that can occur:
- Anastomosis failure
- Stenosis development
- Cardiopulmonary complications
Most patients are ready for discharge after 5-6 days.
When the histology result is available, it is determined whether the patient requires chemotherapy.
If the treatment is considered finished, the following outpatient follow-ups are standard:
- Biannually for the first 5 years with clinical examinations supplemented with CT of abdomen/pelvis and thoracic X-ray
- Annually for the next 5 years