Ablative radiation therapy for locally advanced pancreatic cancer: techniques and results

Marsha Reyngold,Parag Parikh,Christopher H Crane

doi:10.1186/s13014-019-1309-x

Abstract

Standard doses of conventionally fractionated radiation have had minimal to no impact on the survival duration of patients with locally advanced unresectable pancreatic cancer (LAPC). The use of low-dose stereotactic body radiation (SBRT) in 3- to 5-fractionshas thus far produced a modest improvement in median survival with minimal toxicity and shorter duration of treatment, but failed to produce a meaningful difference at 2 years and beyond. A much higher biologically effective dose (BED) is likely needed to achieve tumor ablation The challenge is the delivery of ablative doses near the very sensitive gastrointestinal tract. Advanced organ motion management, image guidance, and adaptive planning techniques enable delivery of ablative doses of radiation (> = 100Gy BED) when more protracted hypofractionated regimens or advanced image guidance and adaptive planning are used. This approach has resulted in encouraging improvements in survival in several studies. This review will summarize the evolution of the radiation technique over time from conventional to ablative and describe the practical aspects of delivering ablative doses near the GI tract using cone beam CT image (CBCT) guidance and online adaptive MRI guidance.

Highlights

Unresectable locally advanced pancreatic cancer continues to carry a grim prognosis with a median survival of 10–16 months even in the context of the significant improvement in chemotherapy options seen in the last two decades [1]
At least a third of the patients die of complications related to local progression with or without any evidence of metastatic disease [2], and local progression may predominate as the cause of death for patients surviving more than 15 months regardless of their metastatic status [2, 3]
Lessons from conventional radiotherapy experience Standard radiotherapy options, commonly delivering 40 to 60 Gy in 1.8–2.0 Gy per fraction add minimal to no survival benefit for patients with locally advanced unresectable pancreatic cancer (LAPC) who have received chemotherapy

Summary

Introduction

Unresectable locally advanced pancreatic cancer continues to carry a grim prognosis with a median survival of 10–16 months even in the context of the significant improvement in chemotherapy options seen in the last two decades [1]. Lessons from conventional radiotherapy experience Standard radiotherapy options, commonly delivering 40 to 60 Gy in 1.8–2.0 Gy per fraction add minimal to no survival benefit for patients with locally advanced unresectable pancreatic cancer (LAPC) who have received chemotherapy. These doses were based on the tolerability of large field radiation to the stomach and duodenum in the 2D and 3-D era, and have been shown to provide a modest local tumor control benefit only.

Results

Conclusion