Objective To investigate the effects of computed tomography (CT) slice thickness, lumpectomy cavity (LC) volume, cavity visualization score (CVS), and number of metal clips on the interobserver and intraobserver variability in the delineation of LC after breast-conserving surgery based on four-dimensional (4D) CT. Methods Thirty-five patients who had underwent breast-conserving surgery and had at least 5 metal clips placed in the LCs underwent 4DCT scans. For each patient, LC was delineated on the CT images in the T50(end-exhalation) phase. The patients were stratified according to LC volume, CVS, CT slice thickness, and number of metal clips. Among different patient groups, interobserver and intraobserver variability in LC (Δinter and Δintra) and the dice similarity coefficients (DSCs) between LCs (DSCinter and DSCintra) were evaluated and compared. Results LC volume, CVS, number of metal clips, and 4DCT slice thickness were not significantly correlated with Δintra and DSCintra (P=0.628,0.842,0.080). There were no significant differences in Δinter and DSCinter between the patient groups with 4DCT slice thickness of 2, 3, and 5 mm (P=0.211 and 0.727), and there was no correlation between 4DCT slice thickness and Δinter and DSCinter (P=0.414,0.594). LC volume was negatively correlated with Δinter (P=0.024);compared with those with LC volumes smaller than the mean value, the patients with LC volumes not smaller than the mean value had a significantly higher DSCinter (P=0.025) and a significantly lower Δinter (P=0.009). The patient group with a CVS of 3－5 had a significantly higher DSCinter than that with a CVS of 1－2(P=0.004), and CVS was positively correlated with DSCinter (P=0.007). There were no significant differences in Δinter and DSCinter between the patient groups with 7－9 and 5－6 metal clips (P=0.159,0.825). Conclusions For the breast cancer patients who have at least 5 metal clips placed at the boundary of LC after breast-conserving surgery, LC volume and CVS are still the main influential factors for variability in LC delineation. More metal clips in addition to 5－6 ones are not helpful for LC delineation.
Corresponding Authors:
LI Jian-bin, Email:lijianbin@msn.com
Cite this article:
WANG Wei,LI Jian-bin,XING Jun et al. Analysis of influential factors for variability in delineation of lumpectomy cavity based on 4DCT in end-exhalation phase[J]. Chinese Journal of Radiation Oncology, 2013, 22(5): 357-360.
WANG Wei,LI Jian-bin,XING Jun et al. Analysis of influential factors for variability in delineation of lumpectomy cavity based on 4DCT in end-exhalation phase[J]. Chinese Journal of Radiation Oncology, 2013, 22(5): 357-360.
[1]Dzhugashvili M, Tournay E, Pichenot C, et al. 3D-conformal accelerated partial breast irradiation treatment planning:the value of surgical clips in the delineation of the lumpectomy cavity. Radiat Oncol,2009,4:70. [2]Dzhugashvili M, Pichenot C, Dunant A, et al. Surgical clips assist in the visualization of the lumpectomy cavity in three-dimensional conformal accelerated partial-breast irradiation. Int J Radiat Oncol Biol Phys,2010,76:1320-1324. [3]Shaikh T, Chen T, Khan A, et al. Improvement in interobserver accuracy in delineation of the lumpectomy cavity using fiducial markers. Int J Radiat Oncol Biol Phys,2010,78:1127-1134. [4]Giezen M, Kouwenhoven E, Scholten AN, et al. MRI-versus CT-based volume delineation of lumpectomy cavity in supine position in breast-conserving therapy:an exploratory study. Int J Radiat Oncol Biol Phys,2012,82:1332-1340. [5]Qi XS, White J, Rabinovitch R, et al. Respiratory organ motion and dosimetric impact on breast and nodal irradiation. Int J Radiat Oncol Biol Phys,2010,78:609-617. [6]Liao ZW, Guan XX, Li FY, et al. Accelerated partial breast irradiation:use of four-dimensional CT for target localization and ssessment of intrafractional motion. Oncol Res,2010,18:503-507. [7]Wang W, Li BJ, Hu HG, et al. Evaluation of dosimetric variance in whole breast forward-planned intensity-modulated radiotherapy based on 4DCT and 3DCT. J Radiat Res,2013,In press. [8]Kirova YM, Castro-Pena P, Hijal T, et al. Improving the definition of tumor bed boost with the use of surgical clips and image registration in breast cancer patients. Int J Radiat Oncol Biol Phys,2010,78:1352-1355. [9]Thureau S, Oden S, Mokaouim R, et al. Assessing the contribution of a standardized method in defining the tumor bed using surgical clips in breast cancer. Cancer Radiother, 2012,16:100-106. [10]徐敏,李建彬,于志强,等.勾画标准培训对乳腺癌保乳术后放疗靶区勾画的作用.中华放射肿瘤学杂志,2012,21:534-538. [11]Ehler ED, Tome WA. On correlated sources of uncertainty in four dimensional computed tomography data sets. Technol Cancer Res Treat,2010,9:299-306. [12]Landis DM, Luo W, Song J, et al. Variability among breast radiation oncologists in delineation of the postsurgical lumpectomy cavity. Int J Radiat Oncol Biol Phys,2007,67:1299-1308. [13]De Ruysscher D, Faivre-Finn C, Nestle U, et al. European Organisation for Research and Treatment of Cancer recommendations for planning and delivery of high-dose, high-precision radiotherapy for lung cancer. J Clin Oncol,2010,28:5301-5310. [14]Zhang Y, Zhou Y, Yang X, et al. Thin slice three dimentional (3D) reconstruction versus CT 3D reconstruction of human breast cancer. Indian J Med Res,2013,137:57-62. [15]Cover KS, Lagerwaard FJ, Senan S. Color intersity projections:a rapid approach for evaluating four-dimensional CT scans in treatment planning. Int J Radiat Oncol Biol Phys,2006,64:954-961. [21]Prendergast B, Indelicato DJ, Grobmyer SR, et al. The dynamic tumor bed:volumetric changes in the lumpectomy cavity during breast-conserving therapy. Int J Radiat Oncol Biol Phys,2009,74:695-701. [22]Kim LH, Vicini F, Yan D. What do recent studies on lumpectomy cavity volume change imply for breast clinical target volumes? Int J Radiat Oncol Biol Phys,2008,72:1-3. [18]Kader HA, Truong PT, Pai R, et al. When is CT-based postoperative seroma most useful to plan partial breast radiotherapy? Evaluation of clinical factors affecting seroma volume and clarity. Int J Radiat Oncol Biol Phys,2008,72:1064-1069. [19]Topolnjak R, de Ruiter P, Remeijer P, et al. Image-guided radiotherapy for breast cancer patients:surgical clips as surrogate for breast excision cavity. Int J Radiat Oncol Biol Phys,2011,81:187-195. [20]Yue NJ, Haffty BG, Kearney T, et al. Tracking the dynamic seroma cavity using fiducial markers in patients treated with accelerated partial breast irradiation using 3D conformal radiotherapy. Med Phys,2013,40:021717. [21]Kirby AN, Jena R, Harris EJ, et al. Tumour bed delineation for partial breast/breast boost radiotherapy:what is the optimal number of implanted markers?Radiother Oncol,2013,106:231-235.
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