Low accrual, close out in November 2025

The MASPAC trial investigates the added benefit of MR-guided adaptive SBRT of the primary tumor embedded between standard chemotherapy cycles for pain control and prevention of pain in patients with metastatic PDAC (mPDAC).

Patients not progressing after 8 weeks of standard of care systemic therapy (SoC-CT: minimum doublet chemotherapy) will be included and randomized between arm A, receiving MR-guided adaptive SBRT of the primary tumor combined with continuation of SoC-CT, and arm B, continuing SoC-CT without SBRT.

Arm A: The primary tumor is treated with SBRT (6.6 Gy x 5) on a MR-LINAC in breath-hold technique. This scheme was shown to have a reasonable toxicity profile on a conventional LINAC. A low toxicity profile is even more important in patients with metastatic and therefore definitively incurable cancer. Therefore, treatment is performed on a MR-LINAC to deliver high doses to the tumor while keeping the toxicity profile as low as possible. For this purpose, daily adaptive planning is performed aiming to maintain stringent dose constraints for organs at risk (duodenum / stomach / bowel / kidney). Chemotherapy will be continued after SBRT. Arm B: Continuing SoC-CT (according to clinical routine appr. 2 weeks after the previous cycle) without SBRT.

Inclusion Criteria:

• Male and female patients with histologically proven, metastatic pancreatic adenocarcinoma of the pancreatic head or body amenable for MR-guided adaptive SBRT with at least stable disease after 8 weeks of standard of care doublet chemotherapy
• age >18 years
• Eastern Cooperative Oncology Group (ECOG) Performance Status 0, 1 or 2
• Ability to follow study instructions and likely to attend and complete all required visits

Exclusion Criteria:

• Subjects not able to give consent
• Subjects without legal capacity who are unable to understand the nature, scope, significance and consequences of this clinical study
• Simultaneous participation in another clinical study or participation in any clinical trial involving an investigational medicinal product or treatment within 30 days prior to beginning of this study
• Subjects with a physical or psychiatric condition which at the investigator's discretion may put the subject at risk, may confound the study results, or may interfere with the subject's participation in this study
• Women of child bearing potential or sexually active males not willing to use effective contraception while on treatment and 12 weeks after the end of treatment (such as oral, injectable, or implantable contraceptives, or intrauterine contraceptive devices) unless they are surgically sterilized / hysterectomized or there are any other criteria considered sufficiently reliable by the investigator in individual cases
• Biopsy proven tumor invasion into the stomach and/or duodenum
• Medically uncontrolled pain