When Constrained by Constraints: Thinking Outside of the Box in Both Technology and Biology

Technological approaches to reduce severe radiation toxicities of definitive radiation therapy in high-risk stage IIIC non-small cell lung cancer (NSCLC) include 1.Modality: Intensity modulated radiation therapy/volumetric arc therapy or intensity modulated proton therapy must be used. 2.Delivery: Breath-hold delivery and/or daily volumetric imaging should be considered to minimize planning target volume (PTV) margin. Adaptive replan after 3 weeks is strongly recommended. 3.Doses: Balancing between target coverage and normal tissue sparing, we could consider PTV = gross tumor volume + 5 mm without clinical target volume margin if needed. Additionally, we could use a simultaneous integrated boost to boost gross tumor volume to a dose of ≥60 Gy while reducing the PTV dose of 45 to 50 Gy as needed.