Yu Yang Soon

MASTERPLAN full publication is out!! The RT volumes are worth a closer look. CTV = primary GTV + nodal GTV + tumour-vessel interface. The TVI extends 5 mm proximally and 5 mm distally along involved/closely adjacent vessels, for patients where surgery is likely. PTV = CTV/ITV + 5 mm. No elective nodal irradiation, and no elective perineural or celiac/SMA plexus volume specified in the protocol. That is a focused target, with gross nodal disease included. Real-time RTQA is a big part of this story. Review identified 36 major planning deviations in 12 patients, reduced to 2 deviations in 2 patients after QA. All plans passed independent review before treatment. As a radiation oncologist, I want that detail alongside the outcomes. Reproducing the treatment means reproducing the contour review, OAR constraints and image guidance too. Also worth keeping the treatment delivery denominator in view: only 40/49 patients assigned to SBRT actually received it (82%). The efficacy analysis is intention-to-treat. It should not be read as an outcome series of patients who all completed SBRT. The surgical numbers need some unpacking. All comparisons below are chemo + SBRT vs chemo alone: ✅ Underwent surgery: 62% vs 44% (29/47 vs 11/25). ✅ Completed resection: 53% vs 44% (25/47 vs 11/25). ✅ R0 among all resected patients: 52% vs 36% (13/25 vs 4/11). ✅ R0 in the resected POPC subset: 62% vs 40% (13/21 vs 4/10). POPC is the potentially operable cohort. So the 62% surgery figure includes exploration without resection, while the 62% R0 figure applies only to resected POPC patients. These are different endpoints with different denominators. None of those between-arm surgical comparisons was statistically significant. The paper also defines R0 as more than 1 mm clearance. Adjuvant chemo is another important difference: 80% vs 36% of resected patients received it (20/25 vs 4/11). That complicates attribution within the treatment pathway. Early progression in the control group may have contributed, so this is a post-randomisation imbalance with more than one possible explanation. The post-hoc analyses were directionally consistent, but the authors explicitly caution about selection bias. For the planning details: PTV_EVAL excluded the GI PRVs, with a minimum 3 mm PRV expansion. OAR constraints took priority over target coverage. Duodenum, stomach and small bowel D0.5cc were each constrained to <33 Gy, with V30 <5 cc. Delivery used standard linacs; breath hold was recommended, and fiducials were placed in 35/40 patients (88%). This is relevant to how we would implement the approach in practice. With no elective nodes, isolated regional nodal relapse was 4% vs 8% (2/49 vs 2/25). Reassuring, although that does not establish the optimal elective volume (especially considering these patients went to surgery - ASTRO/NRG recommends inclusion of elective perineural coverage). Overall G3+ AEs were 70% vs 64% (33/47 vs 16/25). One G3 pancreatitis and one G2 small bowel obstruction were attributed to SBRT. The practical takeaway for me is to keep the target definition and prospective QA attached to the results, and to be precise about what the surgery and R0 numbers actually measure.