Top Line: It’s hard to imagine much improving the safety and local control of ablative lung radiation for early-stage lung cancer, but what if we could tweak it to better influence systemic control?
The Study: A provocative phase 2 trial randomized 51 patients with early-stage non-small cell lung cancer to standard ablative radiation planning per RTOG 0813/0915 or an “optimized” plan that additionally minimized dose to immune-rich structures including V5/V10 to heart, great vessels, thoracic spine, and lymph-node stations. Importantly, multi-objective plan optimization was used considering the competing dose-spill, and no recommended summed constraint across all lymphocyte-containing regions was determined. Nonetheless, the optimized (i.e., immune site-ALARA) plans successfully significantly reduced low-dose exposure to these structures that translated to a smaller decline in absolute lymphocytes count across follow-up with an overall 13% improvement. Grade 3 lymphopenia occurred in 15% of standard-plan patients versus none with immune-sparing plans. The biggest immune benefit came in central tumors, where absolute lymphocyte count reduction was improved by 30%. Exploratory survival analyses hinted at better disease control and survival with immune-sparing plans, but this small trial was not powered for these endpoints.
TBL: Preliminary data suggests that “immune-sparing” ablative lung radiation is feasible without compromising target objectives or other constraints and translates to measurable immune preservation, particularly for central and/or larger tumors. | Wijesooriya, Int J Radiat Oncol Biol Phys 2026
The Study: A provocative phase 2 trial randomized 51 patients with early-stage non-small cell lung cancer to standard ablative radiation planning per RTOG 0813/0915 or an “optimized” plan that additionally minimized dose to immune-rich structures including V5/V10 to heart, great vessels, thoracic spine, and lymph-node stations. Importantly, multi-objective plan optimization was used considering the competing dose-spill, and no recommended summed constraint across all lymphocyte-containing regions was determined. Nonetheless, the optimized (i.e., immune site-ALARA) plans successfully significantly reduced low-dose exposure to these structures that translated to a smaller decline in absolute lymphocytes count across follow-up with an overall 13% improvement. Grade 3 lymphopenia occurred in 15% of standard-plan patients versus none with immune-sparing plans. The biggest immune benefit came in central tumors, where absolute lymphocyte count reduction was improved by 30%. Exploratory survival analyses hinted at better disease control and survival with immune-sparing plans, but this small trial was not powered for these endpoints.
TBL: Preliminary data suggests that “immune-sparing” ablative lung radiation is feasible without compromising target objectives or other constraints and translates to measurable immune preservation, particularly for central and/or larger tumors. | Wijesooriya, Int J Radiat Oncol Biol Phys 2026