MRIdian® – MR-guided radiation therapy for Pancreatic Cancer
Promising results in pancreatic cancer
Some of the greatest potential benefits that have been seen with the MRIdian® have been when treating cancer in the upper abdomen. Pancreatic cancer is particularly challenging to treat with radiation therapy due to the tumor being surrounded by sensitive healthy tissues such as the duodenum. Soft tissue visualization and adaptive replanning and beam gating come in to their own in these environments.
Supported by clinical evidence
A study conducted in 2019 evaluated outcomes of inoperable pancreatic cancer (n=44) treated using MRIdian® with and without dose escalation in a multi-institutional, retrospective, cohort study based on data from five institutions.1
Patients were stratified into high-dose (biologically effective dose (BED10 >70) and standard-dose groups (BED10 ≤70). Treatment fraction adaptation was more common in the high-dose group (83%) vs the standard-dose group (15%). Overall survival (OS), freedom from local failure (FFLF), acute GI toxicity was evaluated after RT.
Key results
High-dose patients (n=24, 55%) had a significant improvement in 2-year OS (49% vs. 30%, p=0.03) (figure 1) and trended towards significance for 2-year
FFLF (77% vs. 57%, p=0.15) compared to standard-dose patients (n=20, 45%).
No G3+ toxicity occurred in the high-dose group.
Fig 1: OS start of radiation therapy stratified by biologically effective dose (BED10)1
Overall survival results are promising
A study carried out by Parikh et al evaluated the outcomes of inoperable cancer patients treated with hypofractionation (HF) and SABR using MR-guided radiation therapy.2
Patients (n=30) with inoperable pancreatic cancer were treated with ablative doses if MR-guided radiation therapy at a single institution. Hypo-fractionated radiation was given with a median prescription dose of 67.5 Gy/15 fractions (range 50-67.5 Gy). All patients receiving hypofractionated radiation received concurrent chemotherapy, consisting of gemcitabine, gemcitabine and nab-paclitaxel, capecitabine of 5FU. SABR was given with a prescription dose of 50 Gy/5 fractions without concurrent chemotherapy. Patients (n=23) received HF radiation and SABR (n=7).
Key results
Median follow-up from diagnosis and from start of RT was 15.3 months and 10.3 months, respectively.
OS from diagnosis at 15 months was 81% for SABR patients and 72% for HF patients; 1-year survival from start of RT was 82% for the SABR patients and 72% for the HF patients.
Patients treated with ablative doses of radiation using HF or SABR, demonstrate improved OS, compared with historical figures.
Furthermore, toxicity with either technique is low.
References
- Rudra S, et al. Cancer Med 2019; 8(5):2123-2132.
- Parikh PJ, et al. Int J Radiat Oncol 2018; 102(3):e79-80.
