ESTRO 2024 - Abstract Book

S1627

Clinical - Lung

ESTRO 2024

Results:

In total, LV-GLS was measured in 378 echocardiographies, with 127, 111, 77, and 63 at baseline, 6 weeks, 6 months, and one year respectively. Ninety-three patients had measurements available both at baseline and 6 weeks after radiotherapy. Thirteen of these (14.0%) developed subclinical LV dysfunction. This prevalence did not rise 6 months after radiotherapy (7 out of 66, 10.6%). On the other side, at 1 year after radiotherapy, this increased to 24.5% (13 out of 53). This is consistent with a gradual deterioration of LV-GLS over time (p=0.003, Figure 2). At 6 weeks after treatment, patients treated with VMAT had worse LV- GLS than those treated with IMPT (β=0.198, p=0.012). A trend for worse LV-GLS was found for lung cancer patients compared to oesophageal cancer patients (β=0.153, p=0.05 at 6 weeks). Pathology, TNM classification, smoking, alcohol usage, cardiac history, hypertension, and diabetes had no effect on LV-GLS change at follow-up (p>0.05). Also, surgical resection before irradiation, induction chemotherapy and adjuvant immunotherapy had no effect on LV-GLS (p>0.05). In the VMAT patient group, increasing MHD worsened the relative change of LV-GLS at one year after radiotherapy (β= -0.483, p=0.014). However, in the IMPT group, MHD did not influence LV- GLS (β=0.264, p=0.18). MHD was significantly higher in the VMAT group than the IMPT group (13.57 Gy vs. 7.36 Gy, p<0.001), suggesting that the impact of treatment modality on LV-GLS may be dose-related. Moreover, the lack of effect in the IMPT group suggests that the changes in LV-GLS occur beyond a certain threshold only.

Conclusion:

Thoracic radiotherapy for lung and oesophageal cancer can cause progressive subclinical deterioration of left ventricular function, with first changes visible as early as 6 weeks after treatment. Although the impact of these early changes needs to be investigated, they may be prevented by reducing the dose to the heart, for example, by using IMPT.