Abstract

Purpose

The purpose of this study was to evaluate the tumor control probability (TCP), normal tissue complication probability (NTCP) and adaptive time management (ATM) in patients who had non-small cell lung cancer (NSCLC) and underwent radiotherapy with same gap length at different treatment weeks.

Material and Methods

Twenty patients’ definitive radiotherapy treatments, completed in 6.5 weeks, were evaluated retrospectively. Three different scenarios with gaps in 5 fractions at different weeks of treatment (2nd, 4th, and 6th week) were planned. Three ATM models (biologically effective dose (C_BED), time-dose-fractionation (C_TDF) and in-house developed (C_InH)) were calculated for each scenario. TCP and NTCP were calculated and compared with the dose-volume histogram (DVH) of each model.

Results

TCP was accepted as 100% in uninterrupted treatments. When treatment was interrupted and not compensated with ATM, the highest TCP difference was determined as 23.46% in the 4th week (p<.001). Based on comparisons of ATM models, the lowest TCP decrease was found in C_InH. Increasing the fraction size by C_InH and C_BED provided more TCP improvement than increasing the number of fractions by C_TDF.

Conclusion

The treatment gap to be given in the middle of the treatment is more challenging in terms of tumor control. Adaptive approaches that maintain overall treatment time while increasing fractional dose offer increased TCP.

中文翻译：

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非小细胞肺癌患者接受根治性放疗的适应性时间管理：不同间隙持续时间情景的剂量学研究

摘要

目的

本研究的目的是评估接受相同间隙长度放疗的非小细胞肺癌（NSCLC）患者的肿瘤控制概率（TCP）、正常组织并发症概率（NTCP）和适应性时间管理（ATM）。在不同的治疗周。

材料与方法

对 20 名患者在 6.5 周内完成的最终放疗进行了回顾性评估。计划了在不同治疗周（第 2、第 4 和第 6 周）的 5 个分数中有间隔的三种不同情况。针对每种情况计算了三个 ATM 模型（生物有效剂量 (C _BED )、时间剂量分级 (C _TDF ) 和内部开发 (C _InH )）。计算 TCP 和 NTCP 并与每个模型的剂量体积直方图 (DVH) 进行比较。

结果

TCP 在不间断治疗中被接受为 100%。当治疗中断且未用 ATM 补偿时，最高 TCP 差异在第 4 周确定为 23.46% ( p <.001)。根据 ATM 模型的比较，发现 C _{InH 中}TCP 减少最低。通过C _InH和C _BED增加馏分大小比通过C _TDF增加馏分数量提供了更多的TCP 改进。

结论

治疗中途给予的治疗间隔在肿瘤控制方面更具挑战性。保持整体治疗时间同时增加部分剂量的适应性方法提供增加的 TCP。