Atlas-based delineation of lymph node levels in head and neck computed tomography images

PURPOSE: Radiotherapy planning requires accurate delineations of the tumor and of the critical structures. Atlas-based segmentation has been shown to be very efficient to automatically delineate brain critical structures. We therefore propose to construct an anatomical atlas of the head and neck region. METHODS AND MATERIALS: Due to the high anatomical variability of this region, an atlas built from a single image as for the brain is not adequate. We address this issue by building a symmetric atlas from a database of manually segmented images. First, we develop an atlas construction method and apply it to a database of 45 Computed Tomography (CT) images from patients with node-negative pharyngo-laryngeal squamous cell carcinoma manually delineated for radiotherapy. Then, we qualitatively and quantitatively evaluate the results generated by the built atlas based on Leave-One-Out framework on the database. RESULTS: We present qualitative and quantitative results using this atlas construction method. The evaluation was performed on a subset of 12 patients among the original CT database of 45 patients. Qualitative results depict visually well delineated structures. The quantitative results are also good, with an error with respect to the best achievable results ranging from 0.196 to 0.404 with a mean of 0.253. CONCLUSIONS: These results show the feasibility of using such an atlas for radiotherapy planning. Many perspectives are raised from this work ranging from extensive validation to the construction of several atlases representing sub-populations, to account for large inter-patient variabilities, and populations with node-positive tumors.     

基于2013版颈部淋巴结分区指南的鼻咽癌淋巴结转移规律与预后价值研究

背景与目的：2013年欧洲肿瘤学会官方杂志Radiotherapy & Oncology发表了新版头颈部肿瘤颈部淋巴结分区指南,对规范颈部淋巴结靶区的勾画有重要意义。该研究采用2013版颈部淋巴结分区指南,旨在探讨鼻咽癌颈部淋巴结转移规律,以及颈部淋巴结影像特征与预后的关系,为将来修订N分期提供依据。方法：回顾性分析本院2009年1月—2010年12月病理诊断明确的、初诊无远处转移、接受调强放射治疗的鼻咽癌患者656例。所有患者治疗前行鼻咽和颈部MRI扫描。回顾分析所有患者的MRI图像,并根据2013版颈部淋巴结分区指南进行重新分区,分析颈部淋巴结转移的影像学特征与预后的关系。结果：中位随访时间为46.9个月。4年无局部复发生存率为91.3%,4年无颈部复发生存率为95.1%,4年无远处转移生存率为87.7%,4年无病生存率为78.5%,4年总生存率为92.8%。最常见的颈部淋巴结转移分区为：Ⅱ区76.2%,Ⅶa区65.1%,其次为Ⅲ区(50.4%),Ⅴa(17.5%)和Ⅳa(11.7%)。淋巴结的跳跃转移率为1.0%。颈部淋巴结阳性的患者中,46.4%的患者有淋巴结坏死,74.4%的患者有包膜外侵犯。单因素分析显示,颈部淋巴结受累侧数、颈部淋巴结最大径≥6 cm、颈部淋巴结坏死、T分期和N分期都是影响无远处转移生存和无病生存的因素(P<0.05)。淋巴结包膜外侵犯有影响无远处转移生存率的趋势(P=0.060)。环状软骨下缘以下的颈部分区受累对无远处转移生存和无病生存无显著影响。多因素分析发现,T分期、淋巴结最大径是影响无远处转移生存的独立预后因素(P<0.05);T分期、淋巴结最大径和淋巴结坏死是影响无病生存的独立预后因素(P<0.05)。结论：该研究阐明了鼻咽癌颈部淋巴结转移规律,发现颈部淋巴结受累侧数、淋巴结最大径、淋巴结坏死是影响远处转移和无病生存的重要因素。下颈部受累对无远处转移生存和无病生存无显著影响。     

Anatomical bases for the radiological delineation of lymph node areas. Major collecting trunks, head and neck.

Cancer spreads locally through direct infiltration into soft tissues or at distance by invading vascular structures, then migrating through the lymphatic or blood flow. Although cancer cells carried in the blood can end in virtually any corner of the body, lymphatic migration is usually stepwise, through successive nodal stops, which can temporarily delay further progression. In radiotherapy, irradiation of lymphatic paths relevant to the localisation of the primary has been common practice for decades. Similarly, excision of cancer is often completed by lymphatic dissection. Both in radiotherapy and in surgery, advanced knowledge of the lymphatic pathways relevant to any tumor location is an important information for treatment preparation and execution. This first part describes the major collecting trunks of the lymphatic system and then the lymphatics of the head and neck providing anatomical bases for the radiological delineation of lymph node areas in the cervical region, it adds to the existing nomenclature of six nodal levels (I-VI), three new areas listed as parotid, buccal and external jugular levels.     

Selection and delineation of lymph node target volumes in head and neck neoplasms]

This article reviews all clinical and pathological data available in the literature supporting the concept of selectivity in the neck nodes to be included in the Clinical Target Volume for head and neck squamous cell carcinoma. Using the terminology of neck node levels and the guidelines for the surgical delineation of these levels proposed by the Committee for Head and Neck Surgery and Oncology of the American Academy for Otolaryngology-Head and Neck Surgery, recommendations are proposed for both the selection and the delineation of lymph node target volumes.     

基于IMRT和RTOG颈部淋巴结分区标准的鼻咽癌N分期研究

目的 建立一个基于IMRT和RTOG颈部淋巴结分区标准的鼻咽癌新N分期。 方法 回顾分析广西医科大学第一附属医院2010—2011年经病理学证实、无DM并接受IMRT的初治鼻咽癌患者324例,根据鼻咽癌UICC/AJCC分期标准(第7版)进行重新分期。Kaplan-Meier法计算生存率,Logrank法单因素预后分析,Cox模型多因素预后分析。 结果 324例患者中269例(83.0%)出现转移淋巴结,中位随访58个月(6~77个月),全组5年OS率为84.8%,DFS率为77.1%,RFS率为92.7%,DMFS率为80.5%。对其中颈部淋巴结阳性患者预后因素分析显示咽后淋巴结、颈部淋巴结水平、侧数是影响鼻咽癌患者预后因素(P值均<0.05)。根据风险比差异确定鼻咽癌新N分期: N₀期为无淋巴结转移;N₁期为Ⅶ_a区或/和单侧上颈(Ⅰ、Ⅱ、Ⅲ、V_a区)淋巴结转移;N₂期为双侧上颈(Ⅰ、Ⅱ、Ⅲ、Ⅴ_aa区)淋巴结转移;N₃期为Ⅳ _a、Ⅴ_b区及以下区域淋巴结转移。 结论 基于IMRT和RTOG颈部淋巴结分区标准的鼻咽癌新N分期更符合现状,并能更客观预测预后、指导治疗。     

Proposed revision of CT-based cervical and thoracic lymph node levels for esophageal cancer in UICC 7th version

Background and purposeTo propose revisions of CT-based cervical and thoracic lymph node levels for esophageal cancer in UICC 7th version.Material and methodsOne hundred and forty-nine patients who underwent surgery were analyzed retrospectively for hypothesis validation, 338 patients who underwent definitive radiotherapy to evaluate the feasibility in clinical work, and 121 patients from another independent cohort for external evaluation. We redefined Level VI in the RTOG consensus guideline of CT-based cervical lymph node levels, and established a new Level 1 in the IASLC guideline of CT-based thoracic lymph node levels. We also shrunk Level 3p. Lymph nodes were assigned into different levels by three criteria.ResultsWe encountered stratification problems in 63 patients by JSED criteria and in 24 patients by RTOG criteria. Multivariate analysis showed that nodal status was independently associated with OS in the three cohorts (p < 0.001). No significant difference was found between the Level 1 only group and the mediastinal nodes only group (p > 0.05).ConclusionsThe proposed hypothesis clearly defined the boundary area between the cervical and thoracic parts, brought more convenience for stratification, better predicted patients’ OS and provided information for both pre-treatment evaluation and multidisciplinary treatment planning.     

头颈部癌大体肿瘤体积MRI与CT定义比较研究

目的 采用病理标本验证基于MRI、CT定义的头颈部癌大体肿瘤体积(GTV)准确性差异,为临床评价两种影像方法提供依据。方法 选取10只新西兰大白兔建立VX₂鳞癌细胞系头颈部癌模型,6例成功。每只荷瘤兔在同一体位及固定下行头颈部MR和CT扫描,随后处死并置于明胶溶液－70℃固定72 h。采用可定位曲线锯按照与影像扫描相同位置及层厚切割标本来获取病理解剖图像。分别在MRI、CT、病理解剖图像上勾画GTV,计算GTV_MRI、GTV_CT、GTV_SA和体积差异比(VDR),双向分类方差分析和配对t检验比较差异。结果 GTV_MRI、GTV_CT、GTV_SA平均值分别为(8.20±2.56)、(8.40±2.20)、(8.11±2.88) cm³(F=0.06,P=0.943)。VDR_MRI-SA、VDR_CT-SA平均值分别为0.180±0.060、0.309±0.091(t=7.49,P=0.001)。结论 基于MRI的头颈部癌GTV定义的准确性优于CT。     

Anatomical bases for the radiological delineation of lymph node areas. Upper limbs, chest and abdomen.

Cancer spreads locally through direct infiltration into soft tissues, or at distance by invading vascular structures, then migrating through the lymphatic or blood flow. Although cancer cells carried in the blood can end in virtually any corner of the body, lymphatic migration is usually stepwise, through successive nodal stops, which can temporarily delay further progression. In radiotherapy, irradiation of lymphatic paths relevant to the localisation of the primary has been common practice for decades. Similarly, excision of cancer is often completed by lymphatic dissection. Both in radiotherapy and in surgery, advanced knowledge of the lymphatic pathways relevant to any tumour location is an important information for treatment preparation and execution. This second part describes the lymphatics of the upper limb, of the thorax and of the upper abdomen. Providing anatomical bases for the radiological delineation of lymph nodes areas in the axilla, in the chest and in the abdomen, it also offers a simplified classification for labeling the mediastinal and intra-abdominal nodal levels, grouped in each location inside three major functional areas (called I, II and III) which are all divided into three sublevels (named a, b or c).     

The prognostic significance of total lymph node number in patients with axillary lymph node-negative breast cancer.

AIM: In node-negative breast cancer patients, several factors for survival have been evaluated and currently, some of them are accepted for their prognostic and/or predictive values after validation in the separate data sets. The prognostic significance of increases in the number of pathologically detectable axillary lymph nodes in the node-negative patients could not been established clearly. To address this question, we have reviewed our patients' records. METHODS: A retrospective cohort study was conducted in pathologically node-negative patients who underwent modified radical mastectomy for stage I and II breast cancer. Survival and multivariate prognostic factor analyses were carried out to determine whether the number of tumour-free lymph nodes in complete axillary dissection material in addition to known factors was significant for the outcomes. RESULTS: Two hundred and seventy consecutive patients were eligible to enter the trial. The median observation time and the median number of tumour-free lymph nodes were 61 (from 30 to 120) months and 18 (from 10 to 44), respectively. The cohort was divided into the groups according to the number of nodes. The 5-year event-free and overall survivals were 92.5 and 98.3% for patients who had 18 lymph nodes or less, and 70 and 86.7% for those who had more than 18 negative nodes, respectively (P < 0.00001). Multivariate analysis for event-free survival demonstrated that the number of lymph nodes (Relative risk: 3.2 and 95% confidence interval: 1.7 to 5.9) in addition to the pathological tumour size and age was the most important independent prognosticator. In similar, multivariate analysis for overall survival showed that the number of lymph nodes together with the tumour size was the significant indicator (RR of cancer-specific dying in patients who had more than 18 nodes: 3.1 and 95% CI: 1.2 to 8.5). CONCLUSION: The increases in number of tumour-free lymph nodes are clinically important and this parameter should be taken into consideration in the breast cancer patients without metastatic lymph nodes.     

Rotterdam and Brussels CT-based neck nodal delineation compared with the surgical levels as defined by the American Academy of Otolaryngology-Head and Neck Surgery

PURPOSE/OBJECTIVE: Rotterdam and Brussels have independently published guidelines for the definition and delineation of CT-based neck nodal Levels I-VI. This paper first reports on the adequacy of contouring of the Rotterdam delineation protocol. Rotterdam and Brussels differed slightly in translating the original surgical level definitions as proposed by the 2002 American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) to CT guidelines. To adapt to the surgical level definitions to come to a unifying concept, adjustments of both CT-based classifications are proposed. METHODS AND MATERIALS: The clinical neck nodal target volumes of patients irradiated in Rotterdam by three-dimensional conformal radiotherapy (3D-CRT) between December 1998 and March 2001 were reviewed. Thirty-four patients with N0 and 27 patients with N+ disease with primary tumors located in the oral cavity (n = 1) oropharynx (n = 24), hypopharynx (n = 7), and larynx (n = 29) were evaluated. Seven patients underwent unilateral (3 N0 patients, 4 N+ patients) and 54 underwent bilateral (31 N0 patients, 23 N+ patients) irradiation of the neck. In 11 N+ patients, 3D-CRT of the neck was followed by unilateral neck dissection. The dose to the primary and nonresected N+ necks was 70 Gy and to the N0 neck was 46 Gy. Neck levels were analyzed for adequacy of contouring, dose distribution, and patterns of relapse. The mean dose and the percentage of the volume receiving a minimum of 95% (V95) or >107% (V107) of the prescribed dose was computed. RESULTS: In 4 patients treated with bilateral 3D-CRT, contouring was not in concordance with the guidelines of the protocol. The V95 and V107 in the 81 adequately contoured N0 necks (63 irradiated N0 necks from 33 N0 patients, 18 irradiated N0 necks from 24 N+ patients) was 95.6% and 6.3%, respectively. For the 26 N+ necks (15 N+ necks from 13 N+ RT-only patients, 11 N+ necks from 11 preoperatively irradiated patients), the V95 and V107 was 94.6% and 6.7%, respectively. With a median follow-up of 29 months, in 4 (8.6%) of 46 patients treated by 3D-CRT only, regional relapse was found. An actuarial regional and locoregional relapse-free survival and disease-free survival rate at 3 years of 90%, 78%, and 68%, respectively, was observed. All regional relapses were observed in the N0 necks of patients with supraglottic laryngeal carcinoma. Taking the surgical 2002 AAO-HNS classification as a reference, adjustments are proposed for the Rotterdam and Brussels delineation protocols to arrive at a unified CT-based neck nodal classification. CONCLUSION: Adequate dose coverage for the Rotterdam CT-based contours of the neck nodal levels was found. In the RT-only patients, only four failures were observed: one regional and three locoregional relapses. As a next step in optimizing the current Rotterdam and Brussels CT-based delineation protocols, adaptations are proposed to resolve the discrepancies compared with the 2002 AAO-HNS surgical classification.     

Prospective assessment of an atlas-based intervention combined with real-time software feedback in contouring lymph node levels and organs-at-risk in the head and neck: Quantitative assessment of conformance to expert delineation

PurposeA number of studies have previously assessed the role of teaching interventions to improve organ-at-risk (OAR) delineation. We present a preliminary study demonstrating the benefit of a combined atlas and real time software-based feedback intervention to aid in contouring of OARs in the head and neck.Methods and MaterialsThe study consisted of a baseline evaluation, a real-time feedback intervention, atlas presentation, and a follow-up evaluation. At baseline evaluation, 8 resident observers contoured 26 OARs on a computed tomography scan without intervention or aid. They then received feedback comparing their contours both statistically and graphically to a set of atlas-based expert contours. Additionally, they received access to an atlas to contour these structures. The resident observers were then asked to contour the same 26 OARs on a separate computed tomography scan with atlas access. In addition, 6 experts (5 radiation oncologists specializing in the head and neck, and 1 neuroradiologist) contoured the 26 OARs on both scans. A simultaneous truth and performance level estimation (STAPLE) composite of the expert contours was used as a gold-standard set for analysis of OAR contouring.ResultsOf the 8 resident observers who initially participated in the study, 7 completed both phases of the study. Dice similarity coefficients were calculated for each user-drawn structure relative to the expert STAPLE composite for each structure. Mean dice similarity coefficients across all structures increased between phase 1 and phase 2 for each resident observer, demonstrating a statistically significant improvement in overall OAR-contouring ability (P < .01). Additionally, intervention improved contouring in 16/26 delineated organs-at-risk across resident observers at a statistically significant level (P ≤ .05) including all otic structures and suprahyoid lymph node levels of the head and neck.ConclusionsOur data suggest that a combined atlas and real-time feedback-based educational intervention detectably improves contouring of OARs in the head and neck.     

Detection and significance of lymph node micro-metastases in patients with node-negative gastric carcinoma

Lymph node ndcrometastases refer to minute cancermetastases in lymph nodes whose diameter is less than 2nun,l'] and they are difficult to be observed with routinehistologic exndnation. In early years serial sectioningwas frequently used in detectingl lymph node ulnicrometastases. Since the 80's inununohistochemicaltechnique has been commonly employed, and recentlyreverse iran s criptas es -polymeras e chain reaction is al s oaPPlied in order to detect ndcrometastases.12--SJ Althoughall techn…     

Selection and delineation of lymph node target volumes in head and neck conformal radiotherapy. Proposal for standardizing terminology and procedure based on the surgical experience.

The increasing use of 3D treatment planning in head and neck radiation oncology has created an urgent need for new guidelines for the selection and the delineation of the neck node areas to be included in the clinical target volume. Surgical literature has provided us with valuable information on the extent of pathological nodal involvement in the neck as a function of the primary tumor site. In addition, few clinical series have also reported information on radiological nodal involvement in those areas not commonly included in radical neck dissection. Taking all these data together, guidelines for the selection of the node levels to be irradiated for the major head and neck sites could be proposed. To fill the missing link between these guidelines and the 3D treatment planning, recommendations for the delineation of these node levels (levels I-VI and retropharyngeal) on CT (or MRI) slices have been proposed using the guidelines outlined by the Committee for Head and Neck Surgery and Oncology of the American Academy for Otolarynology-Head and Neck Surgery. These guidelines were adapted to take into account specific radiological landmarks more easily identified on CT or MRI slices than in the operating field.     

Anatomical bases for the radiological delineation of lymph node areas. Part III: Pelvis and lower limbs

Cancer spreads locally through direct infiltration into soft tissues, or at a distance by invading vascular structures, then migrating through the lymphatic or blood flow. Although cancer cells carried in the blood can end in virtually any corner of the body, lymphatic migration is usually stepwise, through successive nodal stops, which can temporarily delay further progression. In radiotherapy, irradiation of lymphatic paths relevant to the localization of the primary has been common practice for decades. Similarly, excision of cancer is often completed by lymphatic dissection.Both in radiotherapy and in surgery, advanced knowledge of the lymphatic pathways relevant to any tumor location is an important information for treatment preparation and execution. The third part of these series describes the lymphatics of the pelvis and the lower limb. It Provides anatomical bases for the radiological delineation of lymph nodes areas in the pelvic cavity and in the groin. It also offers the first original classification for labeling the intrapelvic nodes, grouped in seven paired volumes (called levels I-VII), functionally linked with one another and lower abdominal levels by eight potential drainage pathways.