KEY POINTS
- This single-center feasibility study included 80 patients receiving definitive thoracic radiotherapy for lung cancer with the esophagus located within 5 mm of the clinical target volume; 33 had non-small cell lung cancer and 47 had small cell lung cancer.
- The injury-effective esophagus encompassed the esophageal segment overlapping the planning target volume plus a 2-cm superior and inferior extension. Mean dose constraints for the spared segment were set at one-third, one-half, or two-thirds of the prescription dose according to planning target volume overlap.
- Esophagus-sparing plans were generated for all patients, and 96.25% achieved planning target volume D95 above 99% of the prescribed dose. The predefined esophagus-sparing constraint was met in 86.25% of cases.
- Acute radiation-induced esophagitis occurred in 30.0% of patients: grade 1 in 18.75%, grade 2 in 10.0%, and grade 3 in 1.25%. No grade 4 or higher events were reported.
- In paired replanning of 10 patients, esophagus sparing reduced total esophageal mean dose from 21.38 Gy to 18.34 Gy (p=0.0371) and spared-region mean dose from 32.19 Gy to 24.51 Gy (p=0.0039), without a significant reduction in planning target volume D95.
CLINICAL TAKEAWAY
A risk-adapted, segment-specific esophagus-sparing objective appears technically feasible for patients receiving definitive thoracic radiotherapy when the target closely abuts the esophagus. The low rate of severe esophagitis is encouraging, but the single-arm, heterogeneous cohort and unmatched historical benchmark make these findings preliminary and hypothesis-generating rather than practice-changing.