老年综合评估状态对老年直肠癌患者放疗摆位误差的影响

Impact of status determined by comprehensive geriatric assessment on setup error during rectal cancer radiotherapy for elderly patients

目的探讨老年综合评估(CGA)状态对老年直肠癌患者放疗摆位误差的影响。方法前瞻性纳入45例≥70岁拟行放疗的老年直肠癌患者, 在治疗前对患者进行CGA。45例患者的中位年龄为77岁, 男28例, 女17例。CGA状态良好组31例, 不良组14例;俯卧位放疗35例, 仰卧位放疗10例。放疗期间通过锥形束CT(CBCT)进行摆位校正, 放疗第1周每天行1次, 之后每周1次。将CBCT图像与定位CT图像进行骨配准融合, 采集左右(x轴)、头脚(y轴)和腹背(z轴)方向上的摆位误差, 共获得338套CBCT图像。采用广义估计方程检验CGA状态和放疗体位对摆位误差的影响。结果全组患者在左右、头脚、腹背方向上的摆位误差分别为(0.24±0.19)、(0.33±0.25)和(0.19±0.15)cm, 头脚方向上的摆位误差明显大于左右方向和腹背方向(Z=-4.86、-7.72, P<0.001), 左右方向上的摆位误差明显大于腹背方向(Z=-2.79,P=0.005)。CGA状态良好组和不良组患者在左右方向上的摆位误差分别为(0.21±0.17)和(0.30±0.22)cm(Z=2.16, P=0.031)。CGA状态良好组和不良组患者在头脚方向和腹背方向上的摆位误差差异均无统计学意义(P>0.05)。俯卧位和仰卧位放疗患者在腹背方向上的摆位误差分别为(0.17±0.13)和(0.27±0.19)cm(Z=2.85, P=0.004)。俯卧位和仰卧位患者在左右方向和头脚方向上的摆位误差差异均无统计学意义(P>0.05)。结论老年直肠癌患者的CGA状态对左右方向上的摆位误差有影响, 临床可能需要调整计划靶区来外扩边界。

Objective To explore the impacts of comprehensive geriatric assessment(CGA)on setup errors during the radiotherapy of elderly patients with rectal cancer.Methods A total of 45 patients over 70 years of age and receiving radiotherapy were enrolled in the study.A comprehensive geriatric assessment was conducted before the radiotherapy.The enrolled patients had a median age of 77 years,including 28 male and 17 female cases.Meanwhile,31 patients were determined to be in a good CGA status and 14 were determined to be in a poor CGA status,and 35 patients received radiotherapy in the prone position and 10 in the supine position.Cone beam CT(CBCT)was used for setup correction during radiotherapy.CBCT was performed daily in the first week and once a week from the second week.By fusing and aligning the CBCT images with simulation CT images according to the lumbar vertebra,setup errors in the left-right(x axis),cranio-caudal(y axis),and anterior-posterior(z axis)directions were obtained.A total of 338 CBCT images were obtained.A generalized linear model was used to evaluate the effects of multiple factors on the setup errors.Results During the radiotherapy,setup errors of all patients were(0.24±0.19)cm in the left-right direction,(0.33±0.25)cm in the cranio-caudal direction,and(0.19±0.15)cm in the anterior-posterior direction.The setup error in the cranio-caudal direction was more than that in the left-right direction and that in the anterior-posterior direction(Z=-4.86,-7.72,P<0.001).The setup error in the left-right direction was greater than that in the anterior-posterior direction(Z=-2.79,P=0.005).The mean setup errors of the good and poor status groups in the left-right direction were(0.21±0.17)and(0.30±0.22)cm,respectively(Z=2.16,P=0.031).There was no statistically significant difference in the setup errors between cranio-caudal direction and anterior-posterior direction(P>0.05).The setup errors in the anterior-posterior direction were(0.17±0.13)and(0.27±0.19)cm,respectively for the prone and supine positions during the radiotherapy(Z=2.85,P=0.004).There was no statistically significant difference in the setup errors between the left-right direction and the cranio-caudal direction(P>0.05).Conclusion The status of CGA elderly patients with rectal cancer affects the setup error in the left-right direction.It may be necessary to clinically adjust the PTV margin.