Esophageal cancer dose escalation using a simultaneous integrated boost technique

Area of Science:

• Radiation Oncology
• Medical Physics
• Oncology

Background:

• Esophageal cancer treatment failures often occur within the gross tumor volume (GTV).
• Previous studies indicate that 75% of radiation therapy (RT) failures are localized to the GTV in unresectable esophageal cancer.
• Optimizing radiation delivery to the GTV is crucial for improving treatment efficacy.

Purpose of the Study:

• To evaluate the feasibility of a simultaneous integrated boost (SIB) technique for selectively escalating radiation dose to the GTV in esophageal cancer patients.
• To compare SIB-IMRT with conventional 2D-CRT and standard IMRT techniques in terms of target coverage and normal tissue sparing.

Main Methods:

• Treatment plans were generated for 10 patients with distal esophageal cancer using four approaches: 2D-CRT (50.4 Gy), 2D-CRT (64.8 Gy), IMRT (50.4 Gy), and SIB-IMRT (64.8 Gy).
• All plans delivered the prescribed dose in 28 fractions with heterogeneity corrections.
• Isodose distributions were analyzed for GTV coverage and exposure of critical organs at risk (heart, lungs, liver, spinal cord).

Main Results:

• The 50.4 Gy IMRT plan significantly reduced cardiac, pulmonary, and hepatic doses compared to 50.4 Gy 2D-CRT.
• The 64.8 Gy SIB-IMRT plan achieved a 28% increase in GTV dose with normal tissue doses comparable to the 50.4 Gy IMRT plan.
• Compared to 50.4 Gy 2D-CRT, 64.8 Gy SIB-IMRT significantly reduced doses to the heart, lungs, liver, and spinal cord.

Conclusions:

• SIB-IMRT enables selective dose escalation to the GTV, the primary site of treatment failure in esophageal cancer.
• This technique allows for simultaneous reduction of radiation dose to critical organs like the heart, lungs, and liver.
• The clinical benefits of SIB-IMRT warrant further systematic investigation and evaluation.