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General Surgery
Gastrointestinal Stromal Tumors
Built from Maingot's Abdominal Operations
What’s inside
9 sections · 132 slides
Overview
- Topics covered
The tumour and its biology
What a stromal tumour is, the cell it grows from, and the switch that is stuck on
- Definition of gastrointestinal stromal tumour
- 0.1-3%
- Two developments that changed management
- Origin of the term
- Cell of origin
- Histologic patterns of gastrointestinal stromal tumour
- Reading the three histologic patterns
- Spindle cell pattern
- Epithelioid cell pattern
- Misclassification before objective criteria
- The KIT receptor and its ligand
- Gain-of-function KIT mutations
- From mutation to tumour growth
- CD117 immunostaining in gastrointestinal stromal tumour
- CD117 staining as the diagnostic marker
- Distinguishing GIST from smooth muscle tumours
- KIT mutation sites and their frequency
- KIT and PDGFRA mutation sites on the receptor
- Reading the receptor diagram
- PDGFRA mutations
- Staining status versus mutation status
- Wild-type gastrointestinal stromal tumour
- Molecular subgroups of gastrointestinal stromal tumour
Who develops these tumours
Age, the inherited settings, and how common the disease is
- Age and sex distribution
- Gastrointestinal stromal tumour in children
- Germline KIT and PDGFRA mutations
- Gastrointestinal stromal tumour in neurofibromatosis type 1
- Carney's triad
- Carney-Stratakis syndrome
- Inherited and syndromic settings
- Incidence estimates
Presentation and diagnosis
Where these tumours sit, how they announce themselves, and which tests settle the diagnosis
- Anatomic distribution of primary tumours
- Uncommon sites of origin
- 69%
- Bleeding as the common presenting symptom
- Tumour rupture and obstruction
- Metastatic disease at diagnosis
- Contrast-enhanced CT as the first imaging test
- CT appearance of a primary gastric stromal tumour
- MRI for rectal and liver disease
- Role of FDG-PET
- Endoscopic appearance
- Endoscopic ultrasound and fine-needle aspiration
- Indications for preoperative biopsy
- Diagnostic pathway for a suspected stromal tumour
Judging how a tumour will behave
Size, mitotic count and site - and what the margin means
- The three established prognostic factors
- Risk assessment for primary gastrointestinal stromal tumours
- Reading the risk table
- Site of origin and risk of progression
- Additional adverse prognostic factors
- Mutation type and outcome
- Resection margin categories
- Margin status and survival
Surgery for primary disease
The operation itself, what to do with very small tumours, and results after resection
- Goals of the operation
- Exploration of the abdomen
- Extent of resection
- When a larger operation is needed
- Lymphadenectomy is not required
- Managing a positive microscopic margin
- Tumours 2 cm or larger
- Subcentimetre gastric tumours
- Gastric tumours of 1 to 2 cm
- Small tumours outside the stomach
- Endoscopic resection is not recommended
- Deciding by size and site
- Laparoscopic resection
- Gastric stromal tumour isolated between traction sutures
- Stomach divided with a linear stapler
- What the laparoscopic images show
- 50%
- Why surgery alone is often not enough
Drug therapy around the operation
Imatinib before surgery, imatinib after surgery, and what the trials showed
- Imatinib and sunitinib
- Rationale for neoadjuvant therapy
- The multicentre neoadjuvant phase II trial
- Optimal duration of preoperative imatinib
- Large gastric stromal tumour before drug therapy
- The same tumour after nine months of imatinib
- What the before and after scans show
- Perioperative imatinib trials: design and eligibility
- Perioperative imatinib trials: remaining studies
- Reading the perioperative trials table
- Adjuvant imatinib trials
- The ACOSOG Z9001 randomised trial
- Limitations of the adjuvant data
- Outstanding questions in adjuvant therapy
Advanced and recurrent disease
Drug therapy first, and the narrow place surgery still holds
- Failure of conventional chemotherapy and radiotherapy
- Imatinib as first-line therapy
- Imatinib dose and dose escalation
- Exon 9 mutations and higher-dose imatinib
- Continuing imatinib indefinitely
- Sunitinib after imatinib failure
- Sunitinib dosing
- Agents under investigation
- Sequence of drug therapy in advanced disease
- Rationale for cytoreductive surgery
- Limited versus generalized progression
- Retrospective series of resection during drug therapy
- Reading the retrospective series table
- Completeness of resection by response category
- Survival by disease status at operation
- Extent and morbidity of cytoreductive operations
- Goals and drug therapy after cytoreduction
- Selecting patients for cytoreductive surgery
- Liver metastasis before imatinib
- The same liver metastasis after eight months of imatinib
- Sequence in a responding patient
- Palliative and emergency surgery
- Unresectable metastatic disease obstructing the stomach
- Extent of tumour before palliative debulking
- What the palliative case shows
- Management schema for primary and advanced disease
- Reading the management schema
Follow-up and summary
Surveillance after resection, and the points worth carrying away
- Surveillance after resection
- Summary: biology and diagnosis
- Summary: treatment
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- Maingot's Abdominal Operations, 12th Edition