The concomitant of non-classical stereotactic body radiotherapy with tislelizumab based on multidisciplinary modalities for leiomyosarcoma: A case report

Background: Stereotactic body radiotherapy (SBRT) and immune checkpoint inhibitors (ICIs) could obtain a certain synergistic effect on bone and soft tissue sarcoma (BSTS). Given its low radiosensitivity, BSTS usually require an irradiation dose >65 Gy to achieve local control. Herein, we developed a non-classical SBRT technique called "onion-shaped simultaneous boost (OSB)," and reported a patient with prostatic leiomyosarcoma which received non-classical SBRT and other systemic treatments.

Methods: In the case, a 49-year-old male patient was diagnosed with prostatic leiomyosarcoma in November 2018. In the radiotherapy plans, the maximum doses of the targets were more than 65 Gy, while the doses of the organs at risk (OARs) were strictly limited.

Results: After receiving radiotherapy, ICI, and other multidisciplinary modalities, the patient achieved partial response (PR).

Conclusion: In this clinical case, we have observed that the OSB technique, which employs an increased per-fraction radiotherapy dose without the need to match the single-fraction doses typical of conventional SBRT, effectively enhances the therapeutic impact on leiomyosarcoma without an increase in radiotherapy-related side effects. By integrating the OSB technique with a multidisciplinary array of antineoplastic strategies, we can more effectively manage sarcomas in clinical practice.