Room: ePoster Forums
Purpose: To evaluate esophageal doses for lung cancer radiotherpay using three radiotherapy techniques: Stereotactic Body Radiotherapy (SBRT), â€˜Low-Modulatedâ€™ Intensity Modulated Radiation Therapy (LM-IMRT), and Three Dimensional Conformal Radiation Therapy (3DCRT).
Methods: Full intensity modulated RT can be undesirable for lung cancer treatment due to the interplay between lung tumor motion and small segment multi-leaf collimator (MLC) movements. In contrast, LM-IMRT is a sparsely intensity modulated radiation therapy technique that limits the degree of modulation, number of segments per beam, and the IMRT segment size during the inverse planning process. In this retrospective study, treatment charts of 210 lung cancer patients treated with radiation therapy or combined chemoradiotherapy between 2014 and 2017 were reviewed. Dosimetric parameters such as mean esophagus dose (MED), Dmax, Dmin, V5, V10, V15, V20, V30, V40, V50, and V60 were derived from the Pinnacle treatment planning system for each patient. One-way ANOVA was used to compare the dosimetric parameters across treatment techniques and Tukey multiple comparison test was used for pairwise comparisons as needed. Statistical analyses were performed using IBM SPSS v.24 and calculated at the 5% significance level (Î±=0.05).
Results: There were significant differences in dosimetric parameters between SBRT and LM-IMRT, and between SBRT and 3DCRT. Although there were no statistically significant differences between LM- IMRT and 3DCRT for mean esophagus dose, V5, V10, V15, and V20, there were significant differences for V30 and V40 for some dose prescriptions; however, after the prescriptions were re-scaled to 60 Gy in 30 fractions, the differences in esophageal doses comparing 3DCRT and LM-IMRT were statistically significant (p<0.05).
Conclusion: The results suggest that the Low-Modulated IMRT was superior to 3DCRT in sparing esophagus during lung irradiation. Our findings can assist clinicians in optimizing treatment technique and dosimetric parameters to minimize esophageal complications during radiation/chemoradiation therapy for lung cancer.