Brief Introduction:
- Aggressive and lethal malignancy
- 6th most common GI malignancy
- Advanced disease at diagnosis
- 80% metastatic at diagnosis
- 20% resectable
Risk Factors:
- Women>Men
- Older age group
- Cholelithiasis
- Smoking
- Salmonella typhi infection- bile carcinogens
- Porcelain Gallbladder
Investigations:
- CT/MRI - not able to differentiate between scarring and residual tumor.
Radiographic features:
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Mass replacing gall bladder - hypoattenuating/isoattenuating mass in gall bladder fossa- leading to biliary obstruction.
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Wall thickening- usually > 1cm. Mimics benign conditions.
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Intraluminal polypoid.
Extension of tumor
- The most common direct extension is - Liver, followed by colon, followed by the duodenum, and followed by the pancreas.
Role of 18F FDG PET/CT in the management of carcinoma gallbladder:
In diagnosis:
- Detection of residual disease in those patients who underwent Cholecystectomy for a benign cause.
- NCCN still doesn’t recommend PET/CT routinely for pre-op workup or response assessment in a carcinoma gall bladder patients but recognises promising results in studies.
Staging:
- To rule out hepatic and extrahepatic metastasis.
- It is not a good method to detect carcinomatosis, especially in small volumes of tumors.
- Signet ring variant of tumor Show variable FDG uptake. Therefore FDG is not ideal for staging in those tumors.
- Leung et al, found that 18F FDG PET/CT has added value as an addition to CT and helps confirm suspicious nodal disease.
- Butte et al, showed that 18F FDG PET/CT has value in staging in patients with T1b or greater stage of tumour and it is better in detecting lymph nodes compared to CT alone.
- Petrowsky et al, showed that 18F FDG PET/CT is superior to CT alone in identifying distant metastases.
Therapeutic decisions:
- FDG PET/CT upstages patients, which leads to a change in the management of the patients.
- It identifies disseminated disease- and prevents aggressive curative attempts.
- Hwang et al, showed that SUVmax from PET/CT is an independent predictor of OS.
- Yoo et al, showed that TLG - a volume based metabolic parameter is predictive of PS and superior to both MTV and SUV.