Stereotactic MRI-guided Adaptive Radiation Therapy (SMART) for Locally Advanced Pancreatic Cancer: A Promising Approach

Abstract

Locally advanced pancreatic cancer (LAPC) is characterized by poor prognosis and low response durability with standard-of-care chemotherapy or chemoradiotherapy treatment. Stereotactic body radiation therapy (SBRT), which has a shorter treatment course than conventionally fractionated radiotherapy and allows for better integration with systemic therapy, may confer a survival benefit but is limited by gastrointestinal toxicity. Stereotactic MRI-guided adaptive radiation therapy (SMART) has recently gained attention for its potential to increase treatment precision and thus minimize this toxicity through continuous real-time soft-tissue imaging during radiotherapy. The case presented here illustrates the promising outcome of a 69-year-old male patient with LAPC treated with SMART with daily adaptive planning and respiratory-gated technique.

Keywords: locally advanced pancreatic cancer; mri-guided adaptive radiotherapy; sbrt; smart.

Figure 1. Diagnostic computed tomography with visible pancreatic body lesion.

Figure 2. A) Dose-volume histogram comparing the treatment plan dosimetry with predicted doses based on fraction 4’s anatomy. The predicted plan significantly violates the prescribed dose constraints for the duodenal loop and stomach and inadequately covers the treatment target. B) Dose-volume histogram illustrating the adapted (delivered) treatment plan. The radiation dose to the organs at risk has been greatly reduced, while PTV coverage has been increased.

(GTV - Gross tumor volume; PTV - Planning target volume)

Figure 3. Daily positional changes and deformations of the duodenum (purple contour) and stomach (green contour).