Locally Advanced Pancreatic Cancer After Systemic Therapy: Ablative MR-guided Radiotherapy

Rationale: About 40% of patients with pancreatic cancer are diagnosed with locally advanced pancreatic cancer (LAPC). Recommended treatment consists of chemotherapy to prevent disease dissemination and prolong survival. Nevertheless, local tumor growth often causes severe morbidity, including pain, gastrointestinal obstruction, and malnutrition. This has a substantial negative impact on health-related quality of life (HRQoL). Eventually, one-third of patients die due to local tumor growth rather than from systemic disease spread. For palliation of symptoms and improved local tumor control, potentially prolonging survival, minimally-invasive ablative therapies may be effective. Online adaptive stereotactic Magnetic Resonance-guided radiotherapy (MRgRT) is an innovative treatment modality that enables high-precision ablative radiotherapy for pancreatic tumors. This potentially improves RT efficacy without increasing the risk of RT-related toxicity. Consequently, MRgRT holds promise for the treatment of pancreatic cancer.

Objective: To investigate the efficacy of stereotactic MRgRT on HRQoL deterioration-free survival, including death as an event, in patients with LAPC after systemic chemotherapy.

Study design: Nationwide randomized controlled trial (1:1 randomization).

Study population: Patients with LAPC according to Dutch Pancreatic Cancer Group (DPCG) criteria who are not eligible for tumor resection after at least two months of chemotherapy (sample size 150 patients). Also, patients with LAPC who are eligible but choose to refrain from chemotherapy and/or surgery can participate in this trial.

Intervention: Patients in the intervention arm receive 50Gy MRgRT in five fractions over two weeks in one of the four Consortium Centers, followed by standard care, either consisting of continuation of chemotherapy or best supportive care. Patients in the control arm continue standard care without ablative MRgRT.

Main study endpoints: The primary outcome is HRQoL deterioration-free survival from the time of randomization, defined as the Time Until Definitive Deterioration (TUDD) including death as an event. HRQoL is evaluated using the EORTC QLQ-C30 Summary Score. The TUDD is defined as a 10-point minimal clinically important difference compared to baseline, with no further improvement of ≥10 points afterwards. All patients will be offered home monitoring using the Trial@home platform to decrease the burden of trial participation.

Inclusion criteria

• Pathology proven pancreatic ductal adenocarcinoma (PDAC);
• At least two (preferably four) months systemic therapy with (m)FOLFIRINOX and/or gemcitabine + nab-paclitaxel; or eligibility for chemotherapy but no initiation of chemotherapy based on patients' wish;
• No option for surgical resection, either because anatomical irresectability based on the surgeon's judgement (assessed on imaging or during explorative laparotomy) and/or frailty (unfit for surgery or chemotherapy) and/or no surgery based on patient's wish.
• No evidence of distant metastatic disease progression, evaluated by CT Thorax / Abdomen / Pelvis and/or PET-CT scan;
• Performance status WHO 0-2.

Exclusion criteria

• Contra-indications for MRI or CT with an intravenous contrast agent according to the protocol of the local radiology and/or radiotherapy departments

• Contraindications for MRgRT, as determined by the involved expert radiation oncologists of the Consortium
• <18 years old
• Pregnancy