NeoSCOPE was a clinical trial of two separate neoadjuvant chemoradiotherapy systematic plans for oesophageal cancer. It was the first multi-centre trial in the United Kingdom to incorporate four-dimensional CT into the radiotherapy arrangement. Despite 4D-CT being widely accepted as a standard of care for junctional esophageal tumors, there is very limited evidence of its benefit over the standard three-dimensional computed tomography (3D-CT). A dosimetric comparison study of 3D vs. 4D-CT plans using NeoSCOPE cases, was undertaken that compared the target volume coverage and dosage to the organs affected by cancer.
Established normal tissue complication probability models were used to evaluate the potential of toxicity reduction using 4D-CT plans in esophageal cancer. The four-dimensional computed tomography resulted in a lower average planning target volume, as well as lower dose levels for the constraints with the comparable target volume coverage. NTCP modeling suggested a major risk reduction of cardiac and pulmonary toxicity using 4D-CT. The studies show that incorporating 4D-CT into treatment planning may significantly reduce the toxicity burden from this treatment procedure. The integral dose and volume of PTV are significantly reduced with 4D-CT. In conclusion, the four-dimensional CT plans resulted in significantly lower doses to critical organs at risk.