ESTRO 2024 - Abstract Book

S3569

Physics - Dose prediction, optimisation and applications of photon and electron planning

ESTRO 2024

Results:

In the first patient, a notable reduction in pain was observed shortly after LRT. Unfortunately, due to the tumor's substantial volume, comorbidities, and the absence of systemic treatment, the patient eventually died. In the case of the second patient, four months after LRT, a follow-up computed tomography scan indicated a decrease in the dimensions of the chest wall infiltration to 124 x 43 mm. Moreover, no areas of pathological contrast enhancement were observed in the irradiated tumor, and the remaining metastatic lesions had regressed. Presently, the patient remains under observation. As of the current assessment (2.5 years post-LRT), the irradiated lesion remains stable and devoid of any pain symptoms. The remaining metastases are being managed through systemic treatment. In the case of the third patient, a CT scan conducted 3 months later unveiled a substantial reduction in tumor volume (pre-radiotherapy: GTV 13/05/2022 - 585.05 cc, post-radiotherapy: GTV 24/08/2022 - 330.77 cc). Furthermore, the lesion in the right 9th rib exhibited significant calcification, providing effective pain relief.

Conclusion:

Despite promising initial efficacy results, the current level of evidence remains limited, highlighting the need for further research to establish solid evidence regarding the effectiveness of LRT. When we consider the potential of LRT, it becomes clear that its broader application in the treatment of large lesions holds significant promise for changing clinical practice. Moreover, the immunomodulatory properties of LRT can be integrated as a key element of multimodal therapies, potentially combining with immunotherapy, offering an excellent future treatment option for patients with very large tumors. The challenge is to develop an optimal PTV drawing scheme and high dose hotspot distribution, as the current understanding of how changing the distribution of dose hotspots geometrically affects biological response across the tumor site remains elusive.

Keywords: Lattice radiotherapy

References:

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