ESTRO 2024 - Abstract Book

S606

Clinical - Breast

ESTRO 2024

Each patient was requested to complete the q-DASH questionnaire, and the physiotherapist conducted a thorough physical examination using a clinical goniometer to evaluate the shoulder range of motion in six different movements (extension, flexion, internal rotation, external rotation, abduction, and adduction). In addition, isometric muscle strength in these same movements was assessed utilizing a handheld dynamometer. These evaluations were carried out at two time points: before and one year after the end of radiotherapy. For every patient, we assessed the difference between their pre-radiotherapy and post-radiotherapy measurements. Clinically significant changes were defined as a qDASH score difference of 15 points or higher, a reduction of at least 10 degrees in range of motion, and a decrease of 20 percent or more in muscle strength [6-8]. We extracted the relative volume of the shoulder that received doses of 20 Gy, 30 Gy, and 40 Gy or higher, as V20, V30, and V40, respectively, from the dose-volume histograms (DVH). Subsequently, we analyzed the correlation between DVH-based dosimetric parameters and the occurrence of significant shoulder impairments using Pearson's correlation test.

Results:

In our study, we found that approximately 20% of patients exhibited a significant deterioration, as indicated by a notable 15-point increase in their qDASH scores. We also observed strong correlations between the before-after difference in abduction ROM and the V30 (correlation coefficient, r: 0.955) and V40 (r: 0.820). Similarly, we found robust correlations between the difference in adduction ROM and the V20 (r: 0.928), V30 (r: 0.950), and V40 (r: 0.893). Regarding internal rotation and external rotation movements, we observed noteworthy correlations with V20, with correlations of 0.888 and 0.948, respectively. It is essential to highlight that no significant association was found regarding strength reduction in above mentioned movements.

Conclusion:

In conclusion, our preliminary findings suggest good correlations between abduction, adduction, external and internal rotation range of motion decrement, and the V20. While this study remains ongoing, with an expanding sample size, we anticipate achieving even more statistically significant results. Our aim is to establish a predictive model as we continue to collect data.