Mangoni Monica, Borghesi Simona, Aristei Cynthia, Becherini Carlotta
Radiotherapy Unit, Oncology Department, Azienda Ospedaliera Universitaria Careggi, University of Florence, Italy.
Radiation Oncology Unit of Arezzo-Valdarno, Azienda USL Toscana Sud Est, Italy.
Rep Pract Oncol Radiother. 2022 Mar 22;27(1):57-62. doi: 10.5603/RPOR.a2022.0005. eCollection 2022.
This paper focuses on the radiobiological mechanisms underlying the effects of stereotactic radiotherapy (SRT ) which, despite SRT expansion, have not yet been fully elucidated. Some authors postulated that radiobiology principles, as applied to conventional fractionations (5R: reoxygenation, repair, repopulation, redistribution, radioresistence), suffice in themselves to account for the excellent clinical results of SRT; others argued that the role of the 5R was limited. Recent preclinical data showed that hypofractionated ablative treatments altered the microenvironment, thus determining cell death either directly or indirectly. Furthermore, dead tumor cells released quantities of antigens, which stimulated antitumor immunity, thus reducing the risk of relapse and metastasis. Better understanding of the radiobiological mechanisms underlying response to high-dose radiation treatment is essential for predicting its short- and long-term effects on the tumor and surrounding healthy tissues and, consequently, for improving its related therapeutic index.
本文聚焦于立体定向放射治疗（SRT）效果背后的放射生物学机制，尽管SRT已得到广泛应用，但其机制尚未完全阐明。一些作者推测，应用于传统分割放疗（5R：再氧合、修复、再增殖、再分布、放射抗拒）的放射生物学原理本身就足以解释SRT出色的临床效果；另一些人则认为5R的作用有限。最近的临床前数据表明，大分割消融治疗改变了微环境，从而直接或间接导致细胞死亡。此外，死亡的肿瘤细胞释放出大量抗原，刺激抗肿瘤免疫，从而降低复发和转移风险。更好地理解高剂量放射治疗反应背后的放射生物学机制，对于预测其对肿瘤和周围健康组织的短期和长期影响至关重要，进而有助于提高其相关治疗指数。
