Quantitative analysis for the interfractional volumetric changes of stereotactic ablative radiotherapy for early-stage or oligo-metastatic lung tumors
10.3760/cma.j.issn.0254-5098.2015.12.008
- VernacularTitle:量化分析早期肺癌和寡转移癌立体定向消融放疗过程中瘤体变化规律
- Author:
Huiyun ZHAO
;
Yanan SUN
;
Hong GE
;
Xiaoli ZHENG
;
Ke YE
;
Chengliang YANG
- Publication Type:Journal Article
- Keywords:
Stereotactic ablative radiotherapy;
Lung tumor;
Interfractional volumetric change;
Organs at risk
- From:
Chinese Journal of Radiological Medicine and Protection
2015;35(12):921-924
- CountryChina
- Language:Chinese
-
Abstract:
Objective To measure the volumetric changes precisely during stereotactic ablative radiotherapy for early-stage and oligo-metastatic lung tumors and optimize the treatment plan timely.Methods From October 2011 to October 2014, 66 patients with 71 early-stage or oligo-metastatic lung tumors received SABR.Median age was 66 years.To measure the volume of tumors, the verification images were registered before each treatment fraction with stimulation images by reference to bone structure.Tumors volume was measured by the first verification images, and were defined as the reference when evaluating the trend of tumors volume change during SABR treatment.Generalized estimated equations were used to analyze the trend of the change of tumors volume over time with several possible predictors.The primary plan (P-plan) was modified when the biological effective dose (BED) of a tumor reached 60 Gy and volume change reached 25％.The modified plan was named as M-plan.Paired t-test was used to compare the dose of organs at risk (OAR) between M-plan and P-plan.Results In 71 tumors, 49 (69％) tumors showed volumetric shrinkage, 21 (30％) tumors showed enlargement and 1 tumor showed invariance.Generalized estimated equation showed no statistical significance (P =0.281) for the volumetric shrinkage of lung tumors.M-plan was made in 26 tumors.Of these tumors, 21 tumors decreased over 25 ％ and the result of paired t-test showed V5 of lung, Dmax and D1.2 cm3 of spinal cord, Dmax and D5 cm3 of esophagus and D30 cm3 of chest wall were statistically different between two plans(t =3.139 ～11.939 ,P＜0.05).5 tumors enlarged over 25％ and the result of paired t-test showed V5 and V20 of lung,Dmax and D1.2cm3 of spinal cord, Dmax of esophagus and D30cm3 of chest wall were statistically different between the two plans(t =-10.436--2.518, P ＜ 0.05).Conclusions Size of lung tumors changed dynamically during SABR, but it is unnecessary to modify treatment plans for all tumors.The tumors which showed obvious volumetric change may benefit from modifying treatment plans.
