Figueredo Negron Carlos Ivan, Gamboa Garay Oscar, Pabón Girón Alexandra, Esguerra Cantillo Jose Alejandro, Guerrero Lizcano Eduardo
Radiation Oncology, Universidad Militar Nueva Granada, Instituto Nacional de Cancerología, Bogotá, D.C., COL.
Medical Physics, Instituto Nacional de Cancerología, Bogotá, D.C., COL.
Cureus. 2022 Dec 25;14(12):e32940. doi: 10.7759/cureus.32940. eCollection 2022 Dec.
Objective The aim of this study was to compare the dosimetric criteria between the intensity-modulated radiation therapy (IMRT) technique with a simultaneous integrated boost (SIB) and the three-dimensional conformal radiation therapy (3DCRT) technique with a sequential boost (SB) plans for patients with locally advanced cervical cancer (LACC). Materials and methods A retrospective dosimetric comparison was performed in 15 patients with locally advanced cervical cancer who had previously been treated with fractions of 1.8 Gy up to doses of 45, 54-55.8, and 59.4 Gy in 28-33 sessions using the three-dimensional conformal radiation therapy (3DCRT) technique with a sequential boost (SB) and who had a new planning that was made using the intensity-modulated radiation therapy (IMRT) technique with a simultaneous integrated boost (SIB) in 25 sessions. The conformity index, quality of coverage, homogeneity index, mean doses, maximum doses, and different organ at risk (OAR) dose constraints were calculated for the dosimetric comparison of treatment plans. Descriptive analysis was performed using measures of central tendency and dispersion for the quantitative variables and absolute and relative frequencies for the qualitative variables. The comparison was made using the Wilcoxon signed rank sum test for a type I error level of 0.05. The statistical software Stata 11 (StataCorp LLC, College Station, Texas, USA) was used in the analysis. Results The mean age of the patients was 52 years, 33% were stage IIIB, and 67% had squamous cell carcinomas. The conformity index was 0.74 and 0.46 (difference: 0.28; p<0.01), the quality of coverage was 0.84 and 0.94 (difference: -0.10; p<0.01), and the homogeneity index was 0.12 and 0.070 (difference: 0.052; p<0.01) for IMRT-SIB and 3DCRT-SB, respectively. When the mean doses of the OARs were compared, all were lower with the IMRT-SIB technique, with statistically significant differences in the rectum and bladder. Conclusions The IMRT-SIB technique achieves a greater conformation of the doses on the treatment volumes with a significant reduction of the doses on the bladder and rectum.
目的 本研究旨在比较局部晚期宫颈癌（LACC）患者采用同步整合加量（SIB）的调强放射治疗（IMRT）技术与采用序贯加量（SB）的三维适形放射治疗（3DCRT）技术的剂量学标准。材料与方法 对15例局部晚期宫颈癌患者进行回顾性剂量学比较，这些患者此前采用三维适形放射治疗（3DCRT）技术及序贯加量（SB），以1.8 Gy的分次剂量进行28 - 33次治疗，剂量达45、54 - 55.8及59.4 Gy，现重新采用同步整合加量（SIB）的调强放射治疗（IMRT）技术进行25次治疗计划制定。计算适形指数、靶区覆盖质量、均匀性指数、平均剂量、最大剂量以及不同危及器官（OAR）的剂量约束，用于治疗计划的剂量学比较。对定量变量采用集中趋势和离散度测量进行描述性分析，对定性变量采用绝对和相对频率进行描述性分析。采用Wilcoxon符号秩和检验进行比较，I型错误水平设定为0.05。分析使用统计软件Stata 11（美国德克萨斯州大学城StataCorp有限责任公司）。结果 患者的平均年龄为52岁，33%为IIIB期，67%为鳞状细胞癌。IMRT - SIB和3DCRT - SB的适形指数分别为0.74和0.46（差值：0.28；p < 0.01），靶区覆盖质量分别为0.84和0.94（差值： - 0.10；p < 0.01），均匀性指数分别为0.12和0.070（差值：0.052；p < 0.01）。比较OAR的平均剂量时，IMRT - SIB技术的所有剂量均较低，直肠和膀胱的剂量差异具有统计学意义。结论 IMRT - SIB技术在治疗靶区实现了更好的剂量适形，同时显著降低了膀胱和直肠的剂量。
