ESTRO meets Asia 2024 - Abstract Book

S407

RTT – Treatment planning, OAR and target definitions

ESTRO meets Asia 2024

Results:

Considering the small number of partial grades of radiation pneumonitis, the combined groups for which the chi square test was performed without correction were combined as follows: grades 0 and 1 were combined as ≤1, and grades 3 and 4 were combined as ≥3. The difference in the ·proportion of impaired lung function between the two groups was not statistically significant(p>0.05) ， but ≤1 impaired was predominant in the IMRT group, and ≥3 was predominant in the VMAT group. In terms of the grouping of lung volumes at different radiotherapy doses, only some groups differed between the two methods: the mean value of V5 was higher in the VMAT method than in the IMRT method (p<0.05), the mean value of V10 and the mean value of V20 were higher in the VMAT method than in the IMRT method (p>0.05) ， and the mean value of V40, V45, V50, and V55 was higher in the IMRT method than in the VMAT (<0.05). The difference in MLD distribution between the two groups was not significant. Time to diagnosis was used as the starting point for survival (data left-censored for 6 patients), and death or event occurrence (after the start of radiotherapy) or last follow-up as the endpoint. Kaplan-Meier curves were used to analyze the overall survival of elderly patients with non-small-cell lung cancer treated in the IMRT group versus the VMAT group. The overall median survival, median survival in the IMRT group, and mean survival valuation in the VMAT group were 58.597months (95% CI 45.937-71.257) 、 49.731 months (95% CI 3.934-65.529) ， and 41.380 months (95% CI 435.36047.401), respectively. We compared the overall survival, recurrence-free survival, and distant metastasis-free survival between the IMRT considering the small sample*size, overall survival may be critically significant, 0S (p=0.057).

Conclusion:

In intermediate to advanced elderly NSCLC patients, we did not directly find differences in the incidence of radiation pneumonitis, overall survival, recurrence-free survival, and distant-transition-free survival in intensity modulated radiotherapy (IMRT) compared with the volume-modulated arc radiotherapy(VMAT) radiotherapy modality.IMRT reduced the extent of low-dose radiation in the lungs compared with VMAT, but the extent of high dose radiation was slightly greater. However, given the small sample size, the overall survival p-value may be critically significant, OS(p=0.057 ) ， larger samples and more center studies are needed for validation.

Keywords: NSCLC, Radiotherapy, Radiation pneumonitis