Institute of Modern Physics, Fudan University, Shanghai, China.
Department of Radiation Oncology, 71141Shanghai Chest Hospital, Shanghai Jiaotong University, Shanghai, China.
Technol Cancer Res Treat. 2022 Jan-Dec;21:15330338221107966. doi: 10.1177/15330338221107966.
To access the comparative dosimetric and radiobiological advantages of two methods of intensity-modulated radiation therapy (IMRT)-based hybrid radiotherapy planning for stage III nonsmall cell lung cancer (NSCLC). Two hybrid planning methods were respectively characterized by conventional fraction radiotherapy (CFRT) and stereotactic body radiotherapy (SBRT) and CFRT and simultaneous integrated boost (SIB) planning. All plans were retrospectively completed using the 2 methods for 20 patients with stage III NSCLC. CFRT and SBRT dose regimes 2 Gy × 30 f and 12.5 Gy × 4 f were, respectively, used for planning target volume of lymph node (PTV) and planning target volume of the primary tumor (PTV), while dose regimes 2 Gy × 26 f for PTV and sequential 2 Gy × 4 f for PTV combined with 12.5 Gy × 4 f for PTV were adopted for CFRT and SIB plans. SBRT and SIB EQD dose were calculated voxel by voxel, and then, respectively, superimposed with 30-fraction and 26-fraction CFRT plan dose to achieve biological equivalent dose (BED) dosimetric parameters of CFRT and SBRT and CFRT and SIB plans. Tumor control probability (TCP)/normal tissue complication probability (NTCP) was, respectively, calculated by equivalent uniform dose/Lyman-Kutcher-Burman models. BED plan parameters and TCP/NTCP were analyzed between 2 methods of hybrid planning. Primary tumor/lymph node (LN)/total TCP values were, respectively, evaluated as a function of the radiation dose needed to control 50% of tumor (TCD) for 20 patients. Dosimetric errors were analyzed by nontransit electronic portal imaging device dosimetry measurement during hybrid plan delivery. Statistically lower BED plan parameters of PTV D and homogeneity index resulted in slightly lower averaged LN/total TCP curves by CFRT and SIB planning. The gaps between Max and Min LN/total TCP curves were significantly closer for CFRT and SIB planning, which indicated better robustness of LN/total TCPs. A lower esophagus dose resulted in a lower esophagus NTCP by CFRT and SIB planning, which may be compromised by 1 week shorter overall treatment time by CFRT and SIB irradiation. Spinal cord was significantly reduced by CFRT and SIB plans. The dose verification results of the subplans involved in hybrid plans were acceptable, which showed that the 2 methods of hybrid planning could be delivered accurately in our center. CFRT and SIB plannings have more advantages on BED plan parameters and TCP/NTCP than CFRT and SBRT planning, and both methods of IMRT-based hybrid planning could be executed accurately for stage III NSCLC. The effectiveness of the results needs to be validated in the hybrid trial.
为了评估两种基于调强放疗（IMRT）的混合放疗计划方法在治疗 III 期非小细胞肺癌（NSCLC）中的比较剂量学和放射生物学优势。这两种混合计划方法分别采用常规分割放疗（CFRT）和立体定向体部放疗（SBRT）以及 CFRT 和同步整合推量（SIB）计划。所有计划均通过 2 种方法对 20 例 III 期 NSCLC 患者进行回顾性完成。CFRT 和 SBRT 剂量方案分别为 2 Gy×30 f 和 12.5 Gy×4 f，用于淋巴结（PTV）和原发肿瘤（PTV）的计划靶区，而 CFRT 和 SIB 计划分别采用 2 Gy×26 f 用于 PTV 和序贯 2 Gy×4 f 用于 PTV 并结合 12.5 Gy×4 f 用于 PTV。SBRT 和 SIB 的 EQD 剂量通过体素进行计算，然后分别与 30 次分割和 26 次分割 CFRT 计划剂量叠加，以实现 CFRT 和 SBRT 以及 CFRT 和 SIB 计划的生物等效剂量（BED）剂量学参数。通过等效均匀剂量/Lyman-Kutcher-Burman 模型分别计算肿瘤控制概率（TCP）/正常组织并发症概率（NTCP）。分析了两种混合计划方法之间的 BED 计划参数和 TCP/NTCP。通过对 20 名患者的 50%肿瘤控制所需的辐射剂量（TCD），评估了原发肿瘤/淋巴结（LN）/总 TCP 值。通过混合计划传输期间的非瞬态电子门成像设备剂量测量分析剂量误差。统计分析表明，CFRT 和 SIB 计划的 PTV D 和均匀性指数的 BED 计划参数较低，导致 LN/总 TCP 曲线的平均值略低。CFRT 和 SIB 计划的最大和最小 LN/总 TCP 曲线之间的差距明显缩小，这表明 LN/总 TCP 更具稳健性。CFRT 和 SIB 计划的食管剂量较低，导致食管 NTCP 较低，这可能因 CFRT 和 SIB 照射的总治疗时间缩短 1 周而受到影响。脊髓剂量明显降低。混合计划中涉及的子计划的剂量验证结果是可以接受的，这表明这两种基于 IMRT 的混合计划方法可以在我们中心准确实施。CFRT 和 SIB 计划在 BED 计划参数和 TCP/NTCP 方面优于 CFRT 和 SBRT 计划，两种基于 IMRT 的混合计划方法均可准确治疗 III 期 NSCLC。结果的有效性需要在混合试验中验证。
