Radiotherapy

Radiotherapy is used in the adjuvant setting although there is no prospective or randomised trials for its use. Doses should be 50.4-54 Gy to subclinical disease (nodes, tumour bed) with a boost to 60 Gy for macroscopic disease.

Adjuvant Radiotherapy

Presimulation

Consider differential evaluation of renal function.
Informed consent.

Simulation

Positioning

Supine

Immobilisation

Hands raised on wing board
Kneefix

Bolus/Modifiers

Not required

Image Acquisition

CT scan from hilum to acetabulum, 3 mm slices, with IV contrast.

  • Consider 4D CT or fluoroscopy to evaluate ITV

Planning

Volumes

GTV = Gross residual disease
CTVp = Tumour Bed
CTVn = Regional nodes (porta hepatis, coeliac axis, peripancreatic)
ITV = CTV + 1 cm (sup/inf) or based on movement seen on 4D CT/fluoroscopy
PTV54 = ITV + 0.5 cm
PTV60 (boost) = GTV + 1.5 - 2.5 cm expansion if needed

Organs at Risk

Liver < 32 Gy mean dose
Kidney < 18 Gy mean dose (or < 6 Gy if one kidney > 18 Gy)
Peritoneum - volume receiving > 45 Gy is no greater than 195 cc
Stomach - < 55 Gy
Spinal cord < 45 Gy

Outcomes

Disease control

50% 5 year survival

Acute Toxicity

Nausea, vomiting, diarrhoea, fatigue, skin reaction

Late Toxicity

Small bowel obstruction 10%, cosmetic skin changes. Liver and kidney should be fine if dose constraints met.


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