SMART achieved durable local control in pancreatic cancer while distant progression dominated

KEY POINTS

• This prospective single-centre cohort included 118 patients with locally advanced pancreatic cancer treated within the MOMENTUM framework. Patients typically received 2–6 months of induction chemotherapy before reassessment and SMART.
• Treatment consisted of 50 Gy in 5 fractions over 7–10 days on a 1.5-T MR-Linac using daily adapt-to-shape replanning, verification MRI and cine-MRI monitoring during free-breathing delivery.
• Local control was encouraging. Cumulative local progression was 15.0% at 1 year and 22.2% at 2 years, whereas distant progression reached 51.7% and 57.6%, respectively.
• Among patients with documented progression, 72% first progressed distantly versus 28% locally. Median time to distant progression as the first failure was only 3.7 months, emphasizing the systemic nature of the disease.
• Median survival from SMART was 13.2 months, with 23.9% alive at 2 years. From initial pancreatic cancer diagnosis, median survival was 19.6 months, with 2-year survival of 40.4%.
• Median progression-free survival from SMART was 5.6 months, and 2-year PFS was 14.8%. Eight patients subsequently underwent surgery.
• Gastrointestinal constraints frequently limited target coverage: median GTV V47.5 Gy was 95.9% in baseline plans and 94.0% across adaptive plans, and the ≥99% coverage goal was achieved in only a minority of patients because OAR limits were prioritized.
• Acute grade ≥3 toxicity occurred in 5.4% of assessed patients. Severe events included one grade 4 ulcer perforation and one grade 5 duodenal perforation, both considered potentially treatment-related. Late grade ≥3 toxicity was reported in 3.2% of evaluable patients.

CLINICAL TAKEAWAY

SOURCE

Radiotherapy and Oncology