Multi-criteria Optimization Achieves Superior Normal Tissue Sparing in a Planning Study of Intensity-modulated Radiation Therapy for RTOG 1308-eligible Non-small Cell Lung Cancer Patients

Purpose: In this planning study, we studied the benefit of intensity-modulated radiation therapy (IMRT) with multi-criteria optimization (MCO) in locally advanced non-small cell lung carcinoma (NSCLC).

Methods: We selected 10 consecutive patients with gross tumor within 1cm of the esophagus eligible for RTOG 1308, randomized phase II trial of 70 Gy protons vs photons. Planning was performed per protocol. In addition, a novel approach for esophagus sparing was applied by making the contralateral esophagus (CE) an avoidance structure. MCO and non-MCO plans underwent double-blinded review. Plan differences in dose-volume histogram parameters were analyzed.

Results: Median plan differences were mean lung dose=0.8 Gy (p=0.01), lung V20=1.1% (p=0.06), heart V30=1.0% (p=0.03), heart V45=0.6% (p=0.03), esophagus V60=1.2% (p=0.04), and CE V45=3.2% (p=0.01), all favoring MCO over non-MCO. PTV coverage with 95% dose was ⩾98.0% for both plans. There were 5 minor protocol deviations with non-MCO plans and 2 with MCO. Median improvement of active planning time with MCO was 88 min (p<0.01). Physicians preferred 8 MCO and 2 non-MCO plans (p=0.04).

Conclusions: MCO plans yielded significant improvements in organ-at-risk sparing without compromising target coverage, consumed less dosimetrist time, and were preferred by physicians. We suggest incorporating MCO into prospective clinical trials.