Reinartz Gabriele, Baehr Andrea, Kittel Christopher, Oertel Michael, Haverkamp Uwe, Eich Hans Th
Department of Radiation Oncology, University Hospital Münster, Albert-Schweitzer-Campus 1, 48149 Münster, Germany.
Cancers (Basel). 2021 Mar 19;13(6):1390. doi: 10.3390/cancers13061390.
Successful studies on radiation therapy for gastric lymphoma led to a decrease in planning target volume (PTV) and radiation dose with low toxicities, maintaining excellent survival rates. It remains unclear as to which effects are to be expected concerning dose burden on organs at risk (OAR) by decrease in PTV vs. dose and whether a direct impact on toxicity might be expected. We evaluated 72 radiation plans, generated prospectively for a cohort of 18 patients who were treated for indolent gastric lymphoma in our department. As a prospective work, four radiation plans with different radiation doses and target volumes (40 Gy-involved field, 40 Gy-involved site, 30 Gy-involved field, 30 Gy-involved site) were generated for each patient. Mean dose burden on adjacent organs was compared between the planning groups. Cohort toxicity data served to estimate parameters for the Lyman-Kutcher-Burman (LKB) model for normal tissue complication probability (NTCP). These were used to anticipate adverse events for OAR. Literature parameters were used to estimate high-grade toxicities of OAR. Decrease of dose and/or PTV led to median dose reductions between 0.13 and 5.2 Gy, with a significant dose reduction on neighboring organs. Estimated model parameters for liver, spleen, and bowel toxicity were feasible to predict cohort toxicities. NTCP for the endpoints elevated liver enzymes, low platelet count, and diarrhea ranged between 15.9 and 22.8%, 27.6 and 32.4%, and 21.8 and 26.4% for the respective four plan variations. Field and dose reduction highly impact dose burden and NTCP for OAR during stomach radiation. Our estimated LKB model parameters offer a good approximation for low-grade toxicities in abdominal organs with modern radiation techniques.
关于胃淋巴瘤放射治疗的成功研究使得计划靶体积（PTV）和放射剂量降低，且毒性较低，同时保持了优异的生存率。目前尚不清楚PTV降低与剂量降低对危及器官（OAR）剂量负担的预期影响，以及是否预期会对毒性产生直接影响。我们评估了72个放射治疗计划，这些计划是前瞻性地为我们科室18例惰性胃淋巴瘤患者制定的。作为一项前瞻性工作，为每位患者生成了四个不同放射剂量和靶体积的放射治疗计划（40 Gy累及野、40 Gy累及部位、30 Gy累及野、30 Gy累及部位）。比较了各计划组相邻器官的平均剂量负担。队列毒性数据用于估计正常组织并发症概率（NTCP）的Lyman-Kutcher-Burman（LKB）模型参数。这些参数用于预测OAR的不良事件。使用文献参数估计OAR的高级别毒性。剂量和/或PTV的降低导致中位剂量减少0.13至5.2 Gy，相邻器官的剂量有显著降低。肝脏、脾脏和肠道毒性的估计模型参数可用于预测队列毒性。对于终点指标肝酶升高、血小板计数降低和腹泻，四个计划变体各自的NTCP范围分别为15.9%至22.8%、27.6%至32.4%和21.8%至26.4%。在胃部放疗期间，野和剂量的减少对OAR的剂量负担和NTCP有很大影响。我们估计的LKB模型参数为采用现代放射技术时腹部器官的低级别毒性提供了良好的近似值。
