Stereotactic radiotherapy and the potential role of magnetic resonance-guided adaptive techniques for pancreatic cancer

Abstract

BACKGROUND Pancreatic cancer is a malignancy with one of the poorest prognoses amongst all cancers. Patients with unresectable tumours either receive palliative care or undergo various chemoradiotherapy regimens. Conventional techniques are often associated with acute gastrointestinal toxicities, as adjacent critical structures such as the duodenum ultimately limits delivered doses. Stereotactic body radiotherapy (SBRT) is an advanced radiation technique that delivers highly ablative radiation split into several fractions, with a steep dose fall-off outside target volumes. AIM To discuss the latest data on SBRT and whether there is a role for magnetic resonance-guided techniques in multimodal management of locally advanced, unresectable pancreatic cancer. METHODS We conducted a search on multiple large databases to collate the latest records on radiotherapy techniques used to treat pancreatic cancer. Out of 1229 total records retrieved from our search, 36 studies were included in this review. RESULTS Studies indicate that SBRT is associated with improved clinical efficacy and toxicity profiles compared to conventional radiotherapy techniques. Further dose escalation to the tumour with SBRT is limited by the poor soft-tissue visualisation of computed tomography imaging during radiation planning and treatment delivery. Magnetic resonance-guided techniques have been introduced to improve imaging quality, enabling treatment plan adaptation and re-optimisation before delivering each fraction. CONCLUSION Therefore, SBRT may lead to improved survival outcomes and safer toxicity profiles compared to conventional techniques, and the addition of magnetic resonance-guided techniques potentially allows dose escalation and conversion of unresectable tumours to operable cases.

Stereotactic ablative radiotherapy or best supportive care in patients with localized pancreatic cancer not receiving chemotherapy and surgery (PANCOSAR): a nationwide multicenter randomized controlled trial according to a TwiCs design

“…These two groups of patients may be sufficiently fit to undergo a short course of stereotactic ablative radiotherapy (SABR). SABR is a non-invasive radiation treatment that is delivered with high precision to the primary tumor in only a few fractions, resulting in a high biological dose to the primary tumor, relatively sparing surrounding organs at risks (OARs) [7][8][9][10].…”

Survival and Toxicity in Patients With Unresectable or Inoperable Biliary Tract Cancers With Ablative Radiation Therapy Versus Nonablative Chemoradiation

“…These findings are consistent with previous studies that evaluated and compared the toxicity profiles of dose escalation or SBRT with conventional fractionation in upper gastrointestinal cancers. 7 , 19 , 21 , 22 , 23…”

Stereotactic Body Radiotherapy (SBRT) of Pancreatic Cancer—A Critical Review and Practical Consideration

“…Further dose escalation to the tumor is limited by poor soft tissue visualization on computed tomography imaging during radiation planning and treatment delivery. Magnetic resonance guided tomography (MRgRT) techniques [ 95 ] have been introduced to improve the quality of imaging and allow for treatment plan adaptation and reoptimization prior to administration of each fraction. Stereotactic MR-guided adaptive radiotherapy (SMART) is a technique combining X-ray beam delivery, daily adaptive treatment planning, and gating/tracking capability using continuous cine MR images.…”