A Consensus-based Guideline Defining the Clinical Target Volume for Pelvic Lymph Nodes in External Beam Radiotherapy for Uterine Cervical Cancer

Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara-cho, Okinawa 903-0215, Japan.
Japanese Journal of Clinical Oncology (Impact Factor: 2.02). 05/2010; 40(5):456-63. DOI: 10.1093/jjco/hyp191
Source: PubMed


To develop a consensus-based guideline as well as an atlas defining pelvic nodal clinical target volumes in external beam radiotherapy for uterine cervical cancer.
A working subgroup to establish the consensus-based guideline on clinical target volumes for uterine cervical cancer was formulated by the Radiation Therapy Study Group of the Japan Clinical Oncology Group in July 2008. The working subgroup consisted of seven radiation oncologists. The process resulting in the consensus included a comparison of contouring on CT images among the members, reviewing of published textbooks and the relevant literature and a distribution analysis of metastatic nodes on computed tomography/magnetic resonance imaging of actual patients.
The working subgroup defined the pelvic nodal clinical target volumes for cervical cancer and developed an associated atlas. As a basic criterion, the lymph node clinical target volume was defined as the area encompassed by a 7 mm margin around the applicable pelvic vessels. Modifications were made in each nodal area to cover adjacent adipose tissues at risk of microscopic nodal metastases. Although the bones and muscles were excluded, the bowel was not routinely excluded in the definition. Each of the following pelvic node regions was defined: common iliac, external iliac, internal iliac, obturator and presacral. Anatomical structures bordering each lymph node region were defined for six directions; anterior, posterior, lateral, medial, cranial and caudal. Drafts of the definition and the atlas were reviewed by members of the JCOG Gynecologic Cancer Study Group (GCSG).
We developed a consensus-based guideline defining the pelvic node clinical target volumes that included an atlas. The guideline will be continuously updated to reflect the ongoing changes in the field.

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    • "In our study, the external iliac lymph nodes contouring was done in accordance with both RTOG[5] where we did not give an extra 10-mm margin for lateral expansion of CTV. A similar recommendation has been made by Toita et al.,[11] who also do not advocate an extra margin for the anterolateral group of external iliac lymph nodes. Moreover, there is a lack of any evidence for isolated failures at the lateral external iliac group of lymph nodes in the literature. "
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    ABSTRACT: With advancements in imaging, wide variations in pelvic anatomy have been observed, thus raising doubts about adequate target volume coverage by conventional external radiotherapy fields based on bony landmarks. The present study evaluates the need for integrating computed tomography (CT)-based planning in the treatment of carcinoma cervix. To estimate inadequacies in target volume coverage when using conventional planning based on bony landmarks. The study consisted of 50 patients. Target volume delineation was done on planning CT scans, according to the guidelines given in literature. The volume of target receiving 95% of prescribed dose (V95) was calculated after superimposing a conventional four field box on digitally reconstructed radiograph. The geographic miss with conventional four field box technique was compared with the CT-based target volume delineation. In 48 out of 50 patients, the conventional four field box failed to encompass the target volume. The areas of miss were at the superior and lateral borders of the anterior-posterior fields, and the anterior border of the lateral fields. The median V95 for conventional fields marked with bony landmarks was only 89.4% as compared to 93% for target delineation based on CT contouring. Our study shows inadequate target volume coverage with conventional four field box technique. We recommend routine use of CT-based planning for treatment with radiotherapy in carcinoma cervix.
    South Asian Journal of Cancer 07/2013; 2(3):132-5. DOI:10.4103/2278-330X.114116
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    • "To minimize the risk of inter-planner variability on pelvic node CTV contouring, consensus-based CTV guidelines have been developed for patients with cervical cancer [2-4]. Modification of the standard CTV guidelines based on the probability of subclinical disease, in other words, risk of recurrence is the next challenge for individualized treatment planning. "
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    ABSTRACT: Background To investigate the three-dimensional (3D) distribution patterns of clinically metastatic (positive) lymph nodes on pretreatment computed tomography (CT)/magnetic resonance imaging (MRI) images of patients with locally advanced cervical cancer. Methods We enrolled 114 patients with uterine cervical cancer with positive nodes by CT/MRI (≥10 mm in the shortest diameter). Pretreatment CT/MRI data were collected at 6 institutions. The FIGO stage was IB1 in 2 patients (2%), IB2 in 6 (5%), IIA in 3 (3%), IIB in 49 (43%), IIIB in 50 (44%), and IVA in 4 (4%) patients. The median cervical tumor diameter assessed by T2-weighted MRI was 55 mm (range, 10–87 mm). The anatomical distribution of the positive nodes was evaluated on CT/MRI images by two radiation oncologists and one diagnostic radiologist. Results In these patients, 273 enlarged nodes were assessed as positive. The incidence of positive nodes was 104/114 (91%) for the obturator region, 31/114 (27%) for the external iliac region, 16/114 (14%) for the internal iliac region, 22/114 (19%) for the common iliac region, and 6/114 (5%) for the presacral region. The external iliac region was subdivided into four sub-regions: lateral, intermediate, medial, and caudal. The obturator region was subdivided into two sub-regions: cranial and caudal. The majority of patients had positive nodes in the cranial obturator and/or the medial external iliac region (111/114). In contrast, few had positive nodes in the lateral external iliac, caudal external iliac, caudal obturator, internal iliac and presacral regions. All cases with positive nodes in those low-risk regions also had positive nodes in other pelvic nodal regions concomitantly. The incidence of positive nodes in the low-risk regions/sub-regions was significantly related to FIGO stage (p=0.017) and number of positive nodes (p<0.001). Conclusions We demonstrated the 3D distribution patterns of clinical metastatic pelvic lymph nodes on pretreatment CT/MRI images of patients with locally advanced cervical cancer. These findings might contribute to future individualization of the clinical target volume of the pelvic nodes in patients with cervical cancer.
    Radiation Oncology 06/2013; 8(1):139. DOI:10.1186/1748-717X-8-139 · 2.55 Impact Factor
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    ABSTRACT: For definitive treatment of carcinoma cervix with conformal radiation techniques, accurate target delineation is vitally important, yet a consensus definition of clinical target volume (CTV) remains variable within the literature. The aim of the present article is to review the guidelines for CTV delineation published in the literature and to present the guidelines practiced at our institute. For this a literature pub med/medline search was performed from January 2000 to December 2012 and reviewed to identify published articles on guidelines for CTV primary and pelvic lymph node (LN) delineation for carcinoma cervix. Taking into consideration the traditional bony landmark based fields for treating cancer cervix, the knowledge of the patterns of disease spread and recurrence and the findings from imaging studies identifying typical anatomic distributions of areas at risk of harbouring subclinical disease, the differences in various guidelines have been analyzed and discussed. The CTV in cervical cancer consists of the CTV nodal and CTV primary. In all the published guidelines, CTV nodal consists of common iliac, external iliac, internal iliac, pre-sacral and obturator group of lymph nodes, and CTV primary consists of the gross tumor volume, uterine cervix, uterine corpus, parametrium, upper third of vagina and uterosacral ligaments. The various guidelines differ however, in the definition for these individual component structures. This is the first report to provide the complete set of guidelines for delineating both the CTV primary and CTV nodal in combination.
    Journal of cancer research and therapeutics 10/2013; 9(4):574-82. DOI:10.4103/0973-1482.126450 · 0.79 Impact Factor
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