- Email: [email protected]
Video-Assisted Mediastinoscopy Compared With Conventional Mediastinoscopy: Are We Doing Better?
Video-Assisted Mediastinoscopy Compared With Conventional Mediastinoscopy: Are We Doing Better? Masaki Anraku, MD, Ryo Miyata, MD, Christopher Compeau, MD, and Yaron Shargall, MD
Background. Conventional mediastinoscopy (CM) is recently being replaced by video-assisted mediastinoscopy (VAM), with potentially better yield and better safety profile for VAM. Methods. All 645 mediastinoscopies (505 CM, 140 VAM) performed between May 2004 and May 2008 were reviewed. Numbers of stations biopsied, total number of lymph nodes dissected, pathology results, and complications were recorded. Patients were divided into two groups: staging for lung cancer group (n ⴝ 500) and diagnostic group (n ⴝ 145). The staging group was further analyzed, using 304 patients who eventually underwent thoracotomy to evaluate accuracy and negative predictive value of mediastinoscopy, comparing between the two methods (233 CM, 71 VAM). Results. Average age was 65 years (range, 26 to 91), and 382 were male. There was no mortality. Eight complica-
tions (1.2%) occurred, more in the VAM group (3.8%) than in the CM group (0.8%; p ⴝ 0.04). The total number of dissected nodes was higher in the VAM group than in the CM group (7.0 ⴞ 3.2 versus 5.0 ⴞ 2.8, p < 0.001), and so was the number of stations sampled (3.6 versus 2.6, p < 0.01). Sensitivity was higher for VAM (95% versus 92.2%, p ⴝ not significant), and so was the negative predictive value (98.6% versus 95.7%, p ⴝ not significant). Most false negative biopsies (8 of 11, 73 %) occurred in station 7. Conclusions. Both methods are safe. More lymph nodes and stations were evaluated by VAM, with trend toward higher negative predictive value. The higher rate of minor complications seen with VAM might be related to a more aggressive and thorough dissection. (Ann Thorac Surg 2010;89:1577– 81) © 2010 by The Society of Thoracic Surgeons
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lung cancer [5, 6], mediastinal lymph node dissection [7, 8], or surgical resection of mediastinal cysts [9]. Potential advantages of VAM over conventional mediastinoscopy (CM) include enhanced and magnified view on the monitor, simplification of teaching and documentation, and a more comfortable working environment for the surgeon. Some VAM devices will also allow the surgeon to use both hands while a double-bladed scope is being held by the assistant [10]. However, only a few reports are currently available that compare the VAM and CM techniques [11]. The objectives of our study were to review our experience with both techniques and to compare them, specifically addressing safety profile, complication rate, number of station or lymph nodes assessed, and accuracy in diagnosis and staging.
ervical mediastinoscopy has been a standard procedure for mediastinal staging of lung cancer or tissue diagnosis of both malignant and benign mediastinal diseases [1, 2]. It is of significant importance to obtain accurate mediastinal staging in lung cancer before starting any type of treatment, as the optimal treatment method and prognosis are clearly stage dependent [3]. Invasive mediastinal staging techniques include mediastinoscopy (cervical, extended cervical, or anterior), endobronchial ultrasonographic needle aspiration (EBUSNA), endoscopic ultrasonographic needle aspiration (EUS-NA), or video-assisted thoracic surgery (VATS). Each procedure can be chosen based on a case-by-case assessment. However, mediastinoscopy might still remain necessary if a nonmalignant result is obtained by a needle technique (ie, EBUS-NA, EUS-NA) in patients with enlarged mediastinal lymph nodes [1]. Video-assisted mediastinoscopy (VAM) has been introduced into several clinical settings, including diagnosis of mediastinal masses or adenopathy, mediastinal staging [4], restaging after induction chemotherapy in Accepted for publication Feb 9, 2010. Presented at the Poster Session of the Forty-fifth Annual Meeting of The Society of Thoracic Surgeons, San Francisco, CA, Jan 26 –28, 2009. Address correspondence to Dr Shargall, Department of Surgery, University of Toronto, Division of Thoracic Surgery, St. Joseph’s Health Centre, 30 The Queensway, SSW W221, Toronto, ON M6R 1B5, Canada; e-mail: [email protected].
© 2010 by The Society of Thoracic Surgeons Published by Elsevier Inc
Material and Methods Patient Population and Data Collection All consecutive patients who underwent CM or VAM between May 2004 and May 2008 at St. Joseph’s Health Centre, University of Toronto, were retrospectively reviewed and analyzed. In our current practice, the vast majority of patients with potentially resectable lung cancer will undergo cervical mediastinoscopy as part of their preoperative staging, excluding only patients with very small (⬍1 cm) peripheral tumors. All patients underwent 0003-4975/10/$36.00 doi:10.1016/j.athoracsur.2010.02.012
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Division of Thoracic Surgery, St. Joseph’s Health Centre, University of Toronto, Toronto, Ontario, Canada
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chest and upper abdominal computed tomography (CT) scans as part of their preoperative staging. Bone and brain scans were used for most patients (excluding several with small, clinically stage IA nonsmall-cell lung cancer). Positron emission tomography (PET) scan was not routinely used. We began utilizing VAM since October 2006 in most cases. The study was approved by the Research Ethics Board of our hospital. The data collected were complete for all patients. Clinical data collected for analyses included age, sex, disease, indication for mediastinoscopy (staging for lung cancer or diagnosis of mediastinal lymphadenopathy/ mediastinal mass), location and size of primary lung tumor, existence of hilar or mediastinal lymphadenopathy, pathologic diagnosis (cell type), type of procedure (CM or VAM), stations biopsied, number of stations biopsied, number of lymph nodes biopsied per each station, perioperative and postoperative complications, and final pathology staging for patients who underwent thoracotomy and lung resection with mediastinal lymph nodes sampling or dissection.
Surgical Technique The surgical techniques of CM and VAM have been previously described [4]. A cervical approach is used, and either the conventional or video-assisted mediastinoscope (Karl Storz, Tuttlingen, Germany) is inserted through a transverse cervical incision along the trachea down to the tracheal bifurcation. Blunt and sharp dissections are performed for biopsy. For staging of lung cancer, mediastinal lymph nodes are assessed according to the American Thoracic Society (ATS) lymph node mapping system [12]. The upper (station 2) and lower (station 4) paratracheal lymph nodes bilaterally, and subcarinal (station 7) lymph nodes are routinely taken for diagnosis if any nodes are identified. The highest mediastinal (station 1) lymph nodes are not routinely biopsied unless clinically indicated (ie, positive PET scan, enlarged nodes detected by CT scan, or enlarged nodes identified during the procedure). Aortopulmonary lymph nodes (stations 5 and 6) are approached using left anterior mediastinoscopy. For patients with lung cancer with no mediastinal disease proved by mediastinoscopy, a node dissection of stations 2R, 4R, 7, 8, 9, and 10R for the right side and stations 5, 6, 7, 8, 9, and 10L on the left side were generally performed at the time of thoracotomy. For obtaining tissue diagnosis of mediastinal lymphadenopathies or mediastinal masses, representative biopsies from an enlarged lymph node or mediastinal mass are taken for diagnosis with an intraoperative pathology assessment. Systematic biopsies are not routinely applied to those cases, unless a frozen section diagnosis of non-small cell lung cancer is made with possible implications for potential future mediastinal radiation or surgical resection after neoadjuvant chemoradiation. In those cases, a full mediastinal lymph node dissection is carried out as for staging purposes. All those patients were referred for postoperative adjuvant chemotherapy after recovering from surgery [13].
Ann Thorac Surg 2010;89:1577– 81
Statistical Analyses Data are presented as means ⫾ SD. Comparisons of continuous values between the two groups (CM versus VAM) were performed by the two-sided t test. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were respectively calculated. False negative rates and complication rates in the VAM group and the CM group were compared by the 2 test. Complication rates in both CM and VAM groups were determined with all study cases (ie, both staging and diagnosis group). Diagnostic accuracy of both methods was assessed in the staging group according to the final pathologic results obtained from mediastinal lymph node sampling/dissection performed during thoracotomy and pulmonary resection. All analyses were performed with JMP 5.0 software (SAS Institute, Cary, NC). All p values less than 0.05 were considered to be statistically significant.
Results A total of 645 consecutive patients underwent mediastinoscopy during the study period. The indications and types of mediastinoscopy were staging for lung cancer in 500 cases (CM ⫽ 396 and VAM ⫽ 104), and tissue diagnosis of mediastinal lymphadenopathy or others in 145 cases (CM ⫽ 109 and VAM ⫽ 36). In the last 2 years of our review, VAM was performed in the majority of patients; and VAM was performed in 21% of cases (104 of 500) in the staging group, and in 25% of cases (36 of 145) in the diagnosis group. The staging group was further analyzed (Table 1). Two thirds of the patients were male in both groups. There was no statistical difference between the groups with regard to male/female ratio (p ⫽ 0.3) and mean age (p ⫽ 0.9). The most dominant cell type was adenocarcinoma (29%) followed by squamous cell carcinoma (19%), large-
Table 1. Patient Demographics (Staging Group, n ⫽ 500) Demographic Age, years, mean ⫾ SD Sex: male/female Cell type, n (%) Adeno carcinoma Squamous cell carcinoma Large cell carcinoma BAC SCLC LCNEC Carcinoid MPM NSCLCa a
Conventional (n ⫽ 396)
Video-Assisted (n ⫽ 104)
68 ⫾ 10 246/150
68 ⫾ 11 64/40
120 (30.0) 90 (7.5) 22 (5.6) 17 (4.3) 18 (4.5) 4 (1.0) 0 (0) 0 (0) 125 (31.6)
26 (25.0) 4 (3.8) 3 (2.9) 4 (3.8) 1 (1.0) 1 (1.0) 1 (1.0) 1 (1.0) 63 (60.6)
Non-small cell lung cancer, cell type undetermined.
BAC ⫽ bronchioloalveolar carcinoma; LCNEC ⫽ large-cell neuroendocrine carcinoma; MPM ⫽ malignant pleural mesothelioma; SCLC ⫽ small cell lung cancer.
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Table 3. Diagnostic Results After Pulmonary Resection Conventional (n ⫽396)
Video-Assisted (n ⫽ 104)
Total (n ⫽ 500)
119 223 0 10 44
19 69 0 1 15
138 292 0 11 59
True positivea True negative False positive False negative Not applicableb
a Thoracotomy for pulmonary resection was not performed in all but 1 case because mediastinoscopy revealed mediastinal lymph node metasb Thoracotomy with lymph node sampling or dissection was not tasis. performed; thus, the results of mediastinoscopy could not be compared with final pathology results.
Station 7 (subcarinal area) was the most predominant station for false negative results (n ⫽ 8) followed by station 4R (n ⫽ 2) and 2R (n ⫽ 1). The only VAM false negative patient was found to have a positive node in station 7 during thoracotomy. Calculated diagnostic performance is demonstrated in Table 4. Sensitivity, negative predictive value, and accuracy were all higher in the VAM group than in the CM group, but the differences did not reach statistical significance. False positive rates were the same (0%) between the groups. There were no perioperative or postoperative deaths in either group. The morbidity rate was 0.8% in the CM group, 2.9% in the VAM group, and 1.2% overall. A total of 8 patients had complications, including perioperative bleeding (n ⫽ 3, 1 CM and 2 VAM), wound infection requiring debridement (n ⫽ 1, CM), left recurrent laryngeal injury (n ⫽ 1, VAM), chyle leak (n ⫽ 1, VAM), postoperative pneumonia (n ⫽ 1, CM), and perioperative myocardial infarction (n ⫽1, CM). One of 2 cases with intraoperative bleeding in the VAM group necessitated median sternotomy for hemostasis because of injury to the first branch of the right pulmonary artery (truncus anterior branch). The patient with chyle leak had an aberrant branch of the thoracic duct along the trachea, running through the lower left paratracheal area. The chyle leak was controlled by clipping of the duct through the same incision, and did not require any further treatment.
Comment Table 2. Number of Lymph Nodes Sampled in Staging Group (n ⫽ 500)
Lymph node station 2R 2L 4R 4L 7 Total lymph nodes per case
Conventional (n ⫽ 396)
Video-Assisted (n ⫽ 104)
p Value
1.8 (1.0) 1.7 (1.0) 2.0 (1.2) 1.8 (1.1) 2.1 (1.2) 5.0 (2.8)
1.8 (0.9) 1.8 (1.1) 2.0 (1.3) 1.8 (1.0) 2.1 (1.2) 7.0 (3.2)
0.9 0.4 0.8 0.8 0.8 ⬍0.001
Video-assisted mediastinoscopy has been reported as a useful tool for mediastinal staging, lymph node dissection, tissue diagnosis of mediastinal diseases, and other Table 4. Diagnostic Performance in Staging Group
Data presented as mean (⫾ SD).
Diagnostic Performance (%) Sensitivity Specificity Positive predictive value Negative predictive value Accuracy
Conventional Video-Assisted 92.2 100 100 95.7 97.2
95.0 100 100 98.6 98.9
All 92.6 100 100 96.4 97.5
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cell carcinoma (5%), bronchioloalveolar carcinoma (4%), and small-cell carcinoma (4%). The proportion of pathologic diagnosis of non-small cell lung cancer without having specific cell type was higher in the VAM group than in the CM group (VAM 60.6% versus CM 31.6%, p ⬍ 0.0001), and that of squamous cell carcinoma was higher in the CM group (VAM 3.8% versus CM 7.5%, p ⬍ 0.0001). There were no statistical differences in the other cell types. The numbers of lymph nodes taken from each station are shown in Table 2. Although there was no difference in the number of lymph nodes taken in each station, the total number of lymph nodes sampled per case was significantly higher in the VAM group than in the CM group (7.0 ⫾ 3.2 versus 5.0 ⫾ 2.8, respectively; p ⬍ 0.001). The percentages of cases biopsied in each station were significantly higher with VAM than with CM in all stations (2R, 74.0% versus 37.1%, p ⬍ 0.001; 2L, 29.8% versus 10.1%, p ⬍ 0.001; 4R, 96.1% versus 88.9%, p ⫽ 0.047; 4L, 79.8% versus 47.2%, p ⬍ 0.001) except station 7 (82.7% versus 78.8%, p ⫽ 0.35). The number of stations sampled per case was also significantly higher in the VAM group than in the CM group (3.6 ⫾ 1.1 stations versus 2.6 ⫾ 1.1 stations, respectively; p ⬍ 0.01). In the staging group (n ⫽ 500), 304 patients (61%) underwent subsequent pulmonary resection and mediastinal lymph node sampling or complete dissection. Of the 304 cases undergoing thoracotomy, all cases but 1 were mediastinoscopy-negative for cancer spread in the mediastinum (N2 disease). The patient with positive N2 disease underwent subsequent thoracotomy for right upper lobectomy because only one node in a single station (4R) was positive for cancer. A total of 196 patients did not undergo definitive resection because of mediastinal lymph node metastases proved by mediastinoscopy (n ⫽ 137) or other reasons (n ⫽ 59). The latter group (59 patients with negative mediastinoscopy who did not undergo definitive surgical resection) consisted mostly of patients who were medically inoperable, as well as several patients who were found to have extrathoracic metastatic disease after having their mediastinoscopy. Eleven of 303 patients with negative mediastinoscopy had metastatic N2 disease found during thoracotomy (false negative rate 3.6%). Of those, 10 patients were from the CM group and 1 was from the VAM group (Table 3).
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therapeutic indications given its superior visualization and ability for surgical maneuvers [4, 9-11]. However, currently there are only few studies that have directly compared VAM to CM with regard to diagnostic performance or complication rate [10, 11]. We found that VAM had better sensitivity, negative predictive value, and false negative rate in comparison with CM, although no statistical differences could be demonstrated. One potential reason might be the relatively small number (104 patients) in the VAM group. In our study, the subcarinal area (station 7) was by far the most problematic area, with 8 of 11 false negative cases occurring in that station (7 CM, 1 VAM). This finding is further supported by a previous report from Cerfolio and coworkers [14]. Their group demonstrated that unsuspected N2 disease was most commonly found in the posterior mediastinal lymph nodes, including those of the distal or posterior portion of station 7. Given the rich blood supply by bronchial artery branches, as well as proximity of surrounding organs (ie, esophagus posteriorly, right pulmonary artery anteriorly, and both right and left main-stem bronchi laterally), one may sample only the top or superficial part of the subcarinal lymph nodes but may miss the deeper posterior or distal part of the nodes. We believe that VAM facilitates better sampling or complete dissection of the lymph nodes as the surgeon can obtain magnified, sharp images on the monitor that allows for clearer visualization of the surrounding structures. Unexpectedly, we experienced higher procedurerelated complication rates in the VAM group when compared with the CM group, perhaps owing to a more aggressive dissection performed with the videoassisted system. Our complication rate was, however, comparable and even lower than that reported by other groups [8, 10, 11]. One of the major advantages of VAM is its greater teaching and training capability, since both trainer and trainee can share the magnified image on the monitor as opposed to a limited operating field visualized only through the mediastinoscope during CM. Thus, the videoassisted system allows for an adequate training and supervision during the procedure. Martin-Ucar and colleagues [15] conducted a prospective study to demonstrate VAM as a useful training tool to learn mediastinoscopy. The investigators concluded that VAM permitted rapid learning without compromising safety to obtain surgical techniques of mediastinal exploration. In our own experience, VAM is being performed by the thoracic surgery trainees in more than 90% of patients, with the staff surgeon scrubbed but not actively performing the procedure. This is in contrast to our experience with CM, in which the staff surgeon performed at least part of the procedure in the vast majority of patients. Video-assisted mediastinoscopy might also contribute to a better standardization and higher yield of the surgical technique of mediastinal staging for lung cancer. Little and colleagues [16] conducted a survey of surgical practice for lung cancer patients (729 hospitals, 11,668 patients) and reported that preoperative mediastinos-
Ann Thorac Surg 2010;89:1577– 81
copy was performed in only 27% of patients undergoing definitive resection for lung cancer. Moreover, lymph nodes were sampled in less than 50% of patients undergoing mediastinoscopy. Although this was an analysis of a survey combining thoracic surgeons and general surgeons performing lung cancer surgery in the United States, with relatively dated data collection (the survey was conducted in 2001), a more recent study analyzing the national Society of Thoracic Surgeons database showed similar problems [17]. In this study written by Boffa and coworkers [17], preresection mediastinoscopy was performed in only 21% of patients (1,922 of 9,033) who underwent lung resection for lung cancer. Moreover, even during surgery, only 61% of patients underwent some form of lymph node assessment (41% lymph nodes “dissection,” 12.4% sampling, and 8% biopsies). Hence, even in the most recent report of surgeries performed by thoracic surgeons, covering the period to 2006, a substantial number of patients did not have complete mediastinal lymph node assessment, before or during the surgical resection. With the impressive safety profile of mediastinoscopy, as demonstrated in our study as well as by others, combined with ease of application, ability for adequate training, and high accuracy of the video-assisted technique, we believe that our report might further support a wider use of VAM with patients evaluated for potentially resectable lung cancer. Although the advent of integrated PET-CT or needle biopsy techniques (ie, EBUS-NA and EUS-NA) provide noninvasive or minimally invasive modalities in mediastinal lymph node staging, mediastinoscopy might still remain the standard procedure of choice for staging of lung cancer [2]. Positive results obtained by noninvasive imaging modality (ie, CT, PET, or PET/CT scan) often require tissue confirmation by invasive techniques [2]. For patients with enlarged mediastinal lymph nodes, or even for those with normal-sized lymph nodes at experienced centers, EBUS-NA can serve as a replacement for mediastinoscopy [18]. However, mediastinoscopy is still required when EBUS-NA gives a negative result in cases with enlarged mediastinal lymph nodes. In conclusion, we demonstrated that VAM is equally safe, with slightly higher sensitivity and negative predictive value, when compared with CM in our practice. Video-assisted mediastinoscopy allowed for evaluation and sampling of more mediastinal stations, and more lymph nodes could be dissected from each station using the technique. The subcarinal area should be carefully assessed as most of the false negative nodes were found in station 7. In that setting, VAM may facilitate thorough and more accurate evaluation. It is possible that a more thorough and liberal dissection of the mediastinum during VAM (given the better visualization and safer perception of the surgeon) might lead to a higher complication rate. Those complications, however, were generally minor and well tolerated, and did not seem to affect the overall outcome.
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References 1. Detterbeck FC, Jantz MA, Wallace M, Vansteenkiste J, Silvestri GA. Invasive mediastinal staging of lung cancer: ACCP evidence-based clinical practice guidelines (2nd edition). Chest 2007;132(Suppl):202–20. 2. De Leyn P, Lardinois D, Van Schil PE, et al. ESTS guidelines for preoperative lymph node staging for non-small cell lung cancer. Eur J Cardiothorac Surg 2007;32:1– 8. 3. Goldstraw P, Crowley J, Chansky K, et al. The IASLC Lung Cancer Staging Project: proposals for the revision of the TNM stage groupings in the forthcoming (seventh) edition of the TNM classification of malignant tumours. J Thorac Oncol 2007;2:706 –14. 4. Venissac N, Alifano M, Mouroux J. Video-assisted mediastinoscopy: experience from 240 consecutive cases. Ann Thorac Surg 2003;76:208 –12. 5. Lardinois D, Schallberger A, Betticher D, Ris HB. Postinduction videomediastinoscopy is as accurate and safe as videomediastinoscopy in patients without pretreatment for potentially operable nonsmall-cell lung cancer. Ann Thorac Surg 2003;75:1102– 6. 6. De Leyn P, Stroobants S, De Wever W, et al. Prospective comparative study of integrated positron emission tomography– computed tomography scan compared with remediastinoscopy in the assessment of residual mediastinal lymph node disease after induction chemotherapy for mediastinoscopy-proven stage IIIA-N2 non-small-cell lung cancer: a Leuven Lung Cancer Group Study. J Clin Oncol 2006;24: 3333–9. 7. Leschber G, Holinka G, Linder A. Video-assisted mediastinoscopic lymphadenectomy (VAMLA)—a method for systematic mediastinal lymph node dissection. Eur J Cardiothorac Surg 2003;24:192–5. 8. Kuzdzal J, Zielinski M, Papla B, et al. Transcervical extended mediastinal lymphadenectomy—the new operative tech-
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nique and early results in lung cancer staging. Eur J Cardiothorac Surg 2005;27:384 –90. Pop D, Venissac N, Leo F, Mouroux J. Video-assisted mediastinoscopy: a useful technique for paratracheal mesothelial cysts. J Thorac Cardiovasc Surg 2005;129:690 –1. Witte B, Wolf M, Huertgen M, Toomes H. Video-assisted mediastinoscopic surgery: clinical feasibility and accuracy of mediastinal lymph node staging. Ann Thorac Surg 2006;82: 1821–7. Leschber G, Sperling D, Klemm W, Merk J. Does videomediastinoscopy improve the results of conventional mediastinoscopy? Eur J Cardiothorac Surg 2008;33:289 –93. Mountain CF, Dresler CM. Regional lymph node classification for lung cancer staging. Chest 1997;111:1718 –23. Detterbeck F. What to do with “surprise” N2?: intraoperative management of patients with non-small cell lung cancer. J Thorac Oncol 2008;3:289 –302. Cerfolio RJ, Bryant AS, Ojha B, Eloubeidi M. Improving the inaccuracies of clinical staging of patients with NSCLC: a prospective trial. Ann Thorac Surg 2005;80:1207–14. Martin-Ucar AE, Chetty GK, Vaughan R, Waller DA. A prospective audit evaluating the role of video-assisted cervical mediastinoscopy (VAM) as a training tool. Eur J Cardiothorac Surg 2004;26:393–5. Little AG, Rusch VW, Bonner JA, et al. Patterns of surgical care of lung cancer patients. Ann Thorac Surg 2005;80: 2051– 6. Boffa DJ, Allen MS, Grab JD, et al. Data from the Society of Thoracic Surgeons general thoracic surgery database: the surgical management of primary lung tumors. J Thorac Cardiovasc Surg 2008;135:247–54. Yasufuku K, Chiyo M, Koh E, et al. Endobronchial ultrasound guided transbronchial needle aspiration for staging of lung cancer. Lung Cancer 2005;50:347–54.
INVITED COMMENTARY This article [1] nicely compares the use of videomediastinoscopy with the use of standard mediastinoscopy in a large number of patients. These operations were performed by a thoracic surgical group with extensive mediastinal staging experience. Although there is a subjective sense to the article, two things seem clear regarding the use of videomediastinoscopy. First, using this technique is of great value for teaching the procedure. I recall Alex Patterson telling me during my training that mediastinoscopy was the hardest and most nerve-racking procedure he taught. I have to agree. With videomediastinoscopy we are finally afforded the opportunity to directly teach the procedure with guidance. Second, the improved visualization may inadvertently lead one to be more aggressive with the dissection. The magnification, combined with the direct nature of the image (as opposed to looking down the tunnel) makes the dissection more enjoyable and immediate, and potentially drawing one
© 2010 by The Society of Thoracic Surgeons Published by Elsevier Inc
in, so to speak, to do a more detailed dissection. Given the last caveat, I believe that videomediastinoscopy should become the standard for mediastinoscopy in general. Michael Maddaus, MD Department of Surgery University of Minnesota Hospital & Clinic 420 Delaware St SE Box 207 Minneapolis, MN 55455 e-mail: [email protected]
Reference 1. Anraku M, Miyata R, Compeau C, Shargall Y. Video-assisted mediastinoscopy compared with conventional mediastinoscopy: are we doing better? Ann Thorac Surg 2010;89:1577– 81.
0003-4975/10/$36.00 doi:10.1016/j.athoracsur.2010.03.032
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Ann Thorac Surg 2010;89:1577– 81
Background. Conventional mediastinoscopy (CM) is recently being replaced by video-assisted mediastinoscopy (VAM), with potentially better yield and better safety profile for VAM. Methods. All 645 mediastinoscopies (505 CM, 140 VAM) performed between May 2004 and May 2008 were reviewed. Numbers of stations biopsied, total number of lymph nodes dissected, pathology results, and complications were recorded. Patients were divided into two groups: staging for lung cancer group (n ⴝ 500) and diagnostic group (n ⴝ 145). The staging group was further analyzed, using 304 patients who eventually underwent thoracotomy to evaluate accuracy and negative predictive value of mediastinoscopy, comparing between the two methods (233 CM, 71 VAM). Results. Average age was 65 years (range, 26 to 91), and 382 were male. There was no mortality. Eight complica-
tions (1.2%) occurred, more in the VAM group (3.8%) than in the CM group (0.8%; p ⴝ 0.04). The total number of dissected nodes was higher in the VAM group than in the CM group (7.0 ⴞ 3.2 versus 5.0 ⴞ 2.8, p < 0.001), and so was the number of stations sampled (3.6 versus 2.6, p < 0.01). Sensitivity was higher for VAM (95% versus 92.2%, p ⴝ not significant), and so was the negative predictive value (98.6% versus 95.7%, p ⴝ not significant). Most false negative biopsies (8 of 11, 73 %) occurred in station 7. Conclusions. Both methods are safe. More lymph nodes and stations were evaluated by VAM, with trend toward higher negative predictive value. The higher rate of minor complications seen with VAM might be related to a more aggressive and thorough dissection. (Ann Thorac Surg 2010;89:1577– 81) © 2010 by The Society of Thoracic Surgeons
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lung cancer [5, 6], mediastinal lymph node dissection [7, 8], or surgical resection of mediastinal cysts [9]. Potential advantages of VAM over conventional mediastinoscopy (CM) include enhanced and magnified view on the monitor, simplification of teaching and documentation, and a more comfortable working environment for the surgeon. Some VAM devices will also allow the surgeon to use both hands while a double-bladed scope is being held by the assistant [10]. However, only a few reports are currently available that compare the VAM and CM techniques [11]. The objectives of our study were to review our experience with both techniques and to compare them, specifically addressing safety profile, complication rate, number of station or lymph nodes assessed, and accuracy in diagnosis and staging.
ervical mediastinoscopy has been a standard procedure for mediastinal staging of lung cancer or tissue diagnosis of both malignant and benign mediastinal diseases [1, 2]. It is of significant importance to obtain accurate mediastinal staging in lung cancer before starting any type of treatment, as the optimal treatment method and prognosis are clearly stage dependent [3]. Invasive mediastinal staging techniques include mediastinoscopy (cervical, extended cervical, or anterior), endobronchial ultrasonographic needle aspiration (EBUSNA), endoscopic ultrasonographic needle aspiration (EUS-NA), or video-assisted thoracic surgery (VATS). Each procedure can be chosen based on a case-by-case assessment. However, mediastinoscopy might still remain necessary if a nonmalignant result is obtained by a needle technique (ie, EBUS-NA, EUS-NA) in patients with enlarged mediastinal lymph nodes [1]. Video-assisted mediastinoscopy (VAM) has been introduced into several clinical settings, including diagnosis of mediastinal masses or adenopathy, mediastinal staging [4], restaging after induction chemotherapy in Accepted for publication Feb 9, 2010. Presented at the Poster Session of the Forty-fifth Annual Meeting of The Society of Thoracic Surgeons, San Francisco, CA, Jan 26 –28, 2009. Address correspondence to Dr Shargall, Department of Surgery, University of Toronto, Division of Thoracic Surgery, St. Joseph’s Health Centre, 30 The Queensway, SSW W221, Toronto, ON M6R 1B5, Canada; e-mail: [email protected].
© 2010 by The Society of Thoracic Surgeons Published by Elsevier Inc
Material and Methods Patient Population and Data Collection All consecutive patients who underwent CM or VAM between May 2004 and May 2008 at St. Joseph’s Health Centre, University of Toronto, were retrospectively reviewed and analyzed. In our current practice, the vast majority of patients with potentially resectable lung cancer will undergo cervical mediastinoscopy as part of their preoperative staging, excluding only patients with very small (⬍1 cm) peripheral tumors. All patients underwent 0003-4975/10/$36.00 doi:10.1016/j.athoracsur.2010.02.012
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Division of Thoracic Surgery, St. Joseph’s Health Centre, University of Toronto, Toronto, Ontario, Canada
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chest and upper abdominal computed tomography (CT) scans as part of their preoperative staging. Bone and brain scans were used for most patients (excluding several with small, clinically stage IA nonsmall-cell lung cancer). Positron emission tomography (PET) scan was not routinely used. We began utilizing VAM since October 2006 in most cases. The study was approved by the Research Ethics Board of our hospital. The data collected were complete for all patients. Clinical data collected for analyses included age, sex, disease, indication for mediastinoscopy (staging for lung cancer or diagnosis of mediastinal lymphadenopathy/ mediastinal mass), location and size of primary lung tumor, existence of hilar or mediastinal lymphadenopathy, pathologic diagnosis (cell type), type of procedure (CM or VAM), stations biopsied, number of stations biopsied, number of lymph nodes biopsied per each station, perioperative and postoperative complications, and final pathology staging for patients who underwent thoracotomy and lung resection with mediastinal lymph nodes sampling or dissection.
Surgical Technique The surgical techniques of CM and VAM have been previously described [4]. A cervical approach is used, and either the conventional or video-assisted mediastinoscope (Karl Storz, Tuttlingen, Germany) is inserted through a transverse cervical incision along the trachea down to the tracheal bifurcation. Blunt and sharp dissections are performed for biopsy. For staging of lung cancer, mediastinal lymph nodes are assessed according to the American Thoracic Society (ATS) lymph node mapping system [12]. The upper (station 2) and lower (station 4) paratracheal lymph nodes bilaterally, and subcarinal (station 7) lymph nodes are routinely taken for diagnosis if any nodes are identified. The highest mediastinal (station 1) lymph nodes are not routinely biopsied unless clinically indicated (ie, positive PET scan, enlarged nodes detected by CT scan, or enlarged nodes identified during the procedure). Aortopulmonary lymph nodes (stations 5 and 6) are approached using left anterior mediastinoscopy. For patients with lung cancer with no mediastinal disease proved by mediastinoscopy, a node dissection of stations 2R, 4R, 7, 8, 9, and 10R for the right side and stations 5, 6, 7, 8, 9, and 10L on the left side were generally performed at the time of thoracotomy. For obtaining tissue diagnosis of mediastinal lymphadenopathies or mediastinal masses, representative biopsies from an enlarged lymph node or mediastinal mass are taken for diagnosis with an intraoperative pathology assessment. Systematic biopsies are not routinely applied to those cases, unless a frozen section diagnosis of non-small cell lung cancer is made with possible implications for potential future mediastinal radiation or surgical resection after neoadjuvant chemoradiation. In those cases, a full mediastinal lymph node dissection is carried out as for staging purposes. All those patients were referred for postoperative adjuvant chemotherapy after recovering from surgery [13].
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Statistical Analyses Data are presented as means ⫾ SD. Comparisons of continuous values between the two groups (CM versus VAM) were performed by the two-sided t test. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were respectively calculated. False negative rates and complication rates in the VAM group and the CM group were compared by the 2 test. Complication rates in both CM and VAM groups were determined with all study cases (ie, both staging and diagnosis group). Diagnostic accuracy of both methods was assessed in the staging group according to the final pathologic results obtained from mediastinal lymph node sampling/dissection performed during thoracotomy and pulmonary resection. All analyses were performed with JMP 5.0 software (SAS Institute, Cary, NC). All p values less than 0.05 were considered to be statistically significant.
Results A total of 645 consecutive patients underwent mediastinoscopy during the study period. The indications and types of mediastinoscopy were staging for lung cancer in 500 cases (CM ⫽ 396 and VAM ⫽ 104), and tissue diagnosis of mediastinal lymphadenopathy or others in 145 cases (CM ⫽ 109 and VAM ⫽ 36). In the last 2 years of our review, VAM was performed in the majority of patients; and VAM was performed in 21% of cases (104 of 500) in the staging group, and in 25% of cases (36 of 145) in the diagnosis group. The staging group was further analyzed (Table 1). Two thirds of the patients were male in both groups. There was no statistical difference between the groups with regard to male/female ratio (p ⫽ 0.3) and mean age (p ⫽ 0.9). The most dominant cell type was adenocarcinoma (29%) followed by squamous cell carcinoma (19%), large-
Table 1. Patient Demographics (Staging Group, n ⫽ 500) Demographic Age, years, mean ⫾ SD Sex: male/female Cell type, n (%) Adeno carcinoma Squamous cell carcinoma Large cell carcinoma BAC SCLC LCNEC Carcinoid MPM NSCLCa a
Conventional (n ⫽ 396)
Video-Assisted (n ⫽ 104)
68 ⫾ 10 246/150
68 ⫾ 11 64/40
120 (30.0) 90 (7.5) 22 (5.6) 17 (4.3) 18 (4.5) 4 (1.0) 0 (0) 0 (0) 125 (31.6)
26 (25.0) 4 (3.8) 3 (2.9) 4 (3.8) 1 (1.0) 1 (1.0) 1 (1.0) 1 (1.0) 63 (60.6)
Non-small cell lung cancer, cell type undetermined.
BAC ⫽ bronchioloalveolar carcinoma; LCNEC ⫽ large-cell neuroendocrine carcinoma; MPM ⫽ malignant pleural mesothelioma; SCLC ⫽ small cell lung cancer.
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Table 3. Diagnostic Results After Pulmonary Resection Conventional (n ⫽396)
Video-Assisted (n ⫽ 104)
Total (n ⫽ 500)
119 223 0 10 44
19 69 0 1 15
138 292 0 11 59
True positivea True negative False positive False negative Not applicableb
a Thoracotomy for pulmonary resection was not performed in all but 1 case because mediastinoscopy revealed mediastinal lymph node metasb Thoracotomy with lymph node sampling or dissection was not tasis. performed; thus, the results of mediastinoscopy could not be compared with final pathology results.
Station 7 (subcarinal area) was the most predominant station for false negative results (n ⫽ 8) followed by station 4R (n ⫽ 2) and 2R (n ⫽ 1). The only VAM false negative patient was found to have a positive node in station 7 during thoracotomy. Calculated diagnostic performance is demonstrated in Table 4. Sensitivity, negative predictive value, and accuracy were all higher in the VAM group than in the CM group, but the differences did not reach statistical significance. False positive rates were the same (0%) between the groups. There were no perioperative or postoperative deaths in either group. The morbidity rate was 0.8% in the CM group, 2.9% in the VAM group, and 1.2% overall. A total of 8 patients had complications, including perioperative bleeding (n ⫽ 3, 1 CM and 2 VAM), wound infection requiring debridement (n ⫽ 1, CM), left recurrent laryngeal injury (n ⫽ 1, VAM), chyle leak (n ⫽ 1, VAM), postoperative pneumonia (n ⫽ 1, CM), and perioperative myocardial infarction (n ⫽1, CM). One of 2 cases with intraoperative bleeding in the VAM group necessitated median sternotomy for hemostasis because of injury to the first branch of the right pulmonary artery (truncus anterior branch). The patient with chyle leak had an aberrant branch of the thoracic duct along the trachea, running through the lower left paratracheal area. The chyle leak was controlled by clipping of the duct through the same incision, and did not require any further treatment.
Comment Table 2. Number of Lymph Nodes Sampled in Staging Group (n ⫽ 500)
Lymph node station 2R 2L 4R 4L 7 Total lymph nodes per case
Conventional (n ⫽ 396)
Video-Assisted (n ⫽ 104)
p Value
1.8 (1.0) 1.7 (1.0) 2.0 (1.2) 1.8 (1.1) 2.1 (1.2) 5.0 (2.8)
1.8 (0.9) 1.8 (1.1) 2.0 (1.3) 1.8 (1.0) 2.1 (1.2) 7.0 (3.2)
0.9 0.4 0.8 0.8 0.8 ⬍0.001
Video-assisted mediastinoscopy has been reported as a useful tool for mediastinal staging, lymph node dissection, tissue diagnosis of mediastinal diseases, and other Table 4. Diagnostic Performance in Staging Group
Data presented as mean (⫾ SD).
Diagnostic Performance (%) Sensitivity Specificity Positive predictive value Negative predictive value Accuracy
Conventional Video-Assisted 92.2 100 100 95.7 97.2
95.0 100 100 98.6 98.9
All 92.6 100 100 96.4 97.5
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cell carcinoma (5%), bronchioloalveolar carcinoma (4%), and small-cell carcinoma (4%). The proportion of pathologic diagnosis of non-small cell lung cancer without having specific cell type was higher in the VAM group than in the CM group (VAM 60.6% versus CM 31.6%, p ⬍ 0.0001), and that of squamous cell carcinoma was higher in the CM group (VAM 3.8% versus CM 7.5%, p ⬍ 0.0001). There were no statistical differences in the other cell types. The numbers of lymph nodes taken from each station are shown in Table 2. Although there was no difference in the number of lymph nodes taken in each station, the total number of lymph nodes sampled per case was significantly higher in the VAM group than in the CM group (7.0 ⫾ 3.2 versus 5.0 ⫾ 2.8, respectively; p ⬍ 0.001). The percentages of cases biopsied in each station were significantly higher with VAM than with CM in all stations (2R, 74.0% versus 37.1%, p ⬍ 0.001; 2L, 29.8% versus 10.1%, p ⬍ 0.001; 4R, 96.1% versus 88.9%, p ⫽ 0.047; 4L, 79.8% versus 47.2%, p ⬍ 0.001) except station 7 (82.7% versus 78.8%, p ⫽ 0.35). The number of stations sampled per case was also significantly higher in the VAM group than in the CM group (3.6 ⫾ 1.1 stations versus 2.6 ⫾ 1.1 stations, respectively; p ⬍ 0.01). In the staging group (n ⫽ 500), 304 patients (61%) underwent subsequent pulmonary resection and mediastinal lymph node sampling or complete dissection. Of the 304 cases undergoing thoracotomy, all cases but 1 were mediastinoscopy-negative for cancer spread in the mediastinum (N2 disease). The patient with positive N2 disease underwent subsequent thoracotomy for right upper lobectomy because only one node in a single station (4R) was positive for cancer. A total of 196 patients did not undergo definitive resection because of mediastinal lymph node metastases proved by mediastinoscopy (n ⫽ 137) or other reasons (n ⫽ 59). The latter group (59 patients with negative mediastinoscopy who did not undergo definitive surgical resection) consisted mostly of patients who were medically inoperable, as well as several patients who were found to have extrathoracic metastatic disease after having their mediastinoscopy. Eleven of 303 patients with negative mediastinoscopy had metastatic N2 disease found during thoracotomy (false negative rate 3.6%). Of those, 10 patients were from the CM group and 1 was from the VAM group (Table 3).
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therapeutic indications given its superior visualization and ability for surgical maneuvers [4, 9-11]. However, currently there are only few studies that have directly compared VAM to CM with regard to diagnostic performance or complication rate [10, 11]. We found that VAM had better sensitivity, negative predictive value, and false negative rate in comparison with CM, although no statistical differences could be demonstrated. One potential reason might be the relatively small number (104 patients) in the VAM group. In our study, the subcarinal area (station 7) was by far the most problematic area, with 8 of 11 false negative cases occurring in that station (7 CM, 1 VAM). This finding is further supported by a previous report from Cerfolio and coworkers [14]. Their group demonstrated that unsuspected N2 disease was most commonly found in the posterior mediastinal lymph nodes, including those of the distal or posterior portion of station 7. Given the rich blood supply by bronchial artery branches, as well as proximity of surrounding organs (ie, esophagus posteriorly, right pulmonary artery anteriorly, and both right and left main-stem bronchi laterally), one may sample only the top or superficial part of the subcarinal lymph nodes but may miss the deeper posterior or distal part of the nodes. We believe that VAM facilitates better sampling or complete dissection of the lymph nodes as the surgeon can obtain magnified, sharp images on the monitor that allows for clearer visualization of the surrounding structures. Unexpectedly, we experienced higher procedurerelated complication rates in the VAM group when compared with the CM group, perhaps owing to a more aggressive dissection performed with the videoassisted system. Our complication rate was, however, comparable and even lower than that reported by other groups [8, 10, 11]. One of the major advantages of VAM is its greater teaching and training capability, since both trainer and trainee can share the magnified image on the monitor as opposed to a limited operating field visualized only through the mediastinoscope during CM. Thus, the videoassisted system allows for an adequate training and supervision during the procedure. Martin-Ucar and colleagues [15] conducted a prospective study to demonstrate VAM as a useful training tool to learn mediastinoscopy. The investigators concluded that VAM permitted rapid learning without compromising safety to obtain surgical techniques of mediastinal exploration. In our own experience, VAM is being performed by the thoracic surgery trainees in more than 90% of patients, with the staff surgeon scrubbed but not actively performing the procedure. This is in contrast to our experience with CM, in which the staff surgeon performed at least part of the procedure in the vast majority of patients. Video-assisted mediastinoscopy might also contribute to a better standardization and higher yield of the surgical technique of mediastinal staging for lung cancer. Little and colleagues [16] conducted a survey of surgical practice for lung cancer patients (729 hospitals, 11,668 patients) and reported that preoperative mediastinos-
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copy was performed in only 27% of patients undergoing definitive resection for lung cancer. Moreover, lymph nodes were sampled in less than 50% of patients undergoing mediastinoscopy. Although this was an analysis of a survey combining thoracic surgeons and general surgeons performing lung cancer surgery in the United States, with relatively dated data collection (the survey was conducted in 2001), a more recent study analyzing the national Society of Thoracic Surgeons database showed similar problems [17]. In this study written by Boffa and coworkers [17], preresection mediastinoscopy was performed in only 21% of patients (1,922 of 9,033) who underwent lung resection for lung cancer. Moreover, even during surgery, only 61% of patients underwent some form of lymph node assessment (41% lymph nodes “dissection,” 12.4% sampling, and 8% biopsies). Hence, even in the most recent report of surgeries performed by thoracic surgeons, covering the period to 2006, a substantial number of patients did not have complete mediastinal lymph node assessment, before or during the surgical resection. With the impressive safety profile of mediastinoscopy, as demonstrated in our study as well as by others, combined with ease of application, ability for adequate training, and high accuracy of the video-assisted technique, we believe that our report might further support a wider use of VAM with patients evaluated for potentially resectable lung cancer. Although the advent of integrated PET-CT or needle biopsy techniques (ie, EBUS-NA and EUS-NA) provide noninvasive or minimally invasive modalities in mediastinal lymph node staging, mediastinoscopy might still remain the standard procedure of choice for staging of lung cancer [2]. Positive results obtained by noninvasive imaging modality (ie, CT, PET, or PET/CT scan) often require tissue confirmation by invasive techniques [2]. For patients with enlarged mediastinal lymph nodes, or even for those with normal-sized lymph nodes at experienced centers, EBUS-NA can serve as a replacement for mediastinoscopy [18]. However, mediastinoscopy is still required when EBUS-NA gives a negative result in cases with enlarged mediastinal lymph nodes. In conclusion, we demonstrated that VAM is equally safe, with slightly higher sensitivity and negative predictive value, when compared with CM in our practice. Video-assisted mediastinoscopy allowed for evaluation and sampling of more mediastinal stations, and more lymph nodes could be dissected from each station using the technique. The subcarinal area should be carefully assessed as most of the false negative nodes were found in station 7. In that setting, VAM may facilitate thorough and more accurate evaluation. It is possible that a more thorough and liberal dissection of the mediastinum during VAM (given the better visualization and safer perception of the surgeon) might lead to a higher complication rate. Those complications, however, were generally minor and well tolerated, and did not seem to affect the overall outcome.
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INVITED COMMENTARY This article [1] nicely compares the use of videomediastinoscopy with the use of standard mediastinoscopy in a large number of patients. These operations were performed by a thoracic surgical group with extensive mediastinal staging experience. Although there is a subjective sense to the article, two things seem clear regarding the use of videomediastinoscopy. First, using this technique is of great value for teaching the procedure. I recall Alex Patterson telling me during my training that mediastinoscopy was the hardest and most nerve-racking procedure he taught. I have to agree. With videomediastinoscopy we are finally afforded the opportunity to directly teach the procedure with guidance. Second, the improved visualization may inadvertently lead one to be more aggressive with the dissection. The magnification, combined with the direct nature of the image (as opposed to looking down the tunnel) makes the dissection more enjoyable and immediate, and potentially drawing one
© 2010 by The Society of Thoracic Surgeons Published by Elsevier Inc
in, so to speak, to do a more detailed dissection. Given the last caveat, I believe that videomediastinoscopy should become the standard for mediastinoscopy in general. Michael Maddaus, MD Department of Surgery University of Minnesota Hospital & Clinic 420 Delaware St SE Box 207 Minneapolis, MN 55455 e-mail: [email protected]
Reference 1. Anraku M, Miyata R, Compeau C, Shargall Y. Video-assisted mediastinoscopy compared with conventional mediastinoscopy: are we doing better? Ann Thorac Surg 2010;89:1577– 81.
0003-4975/10/$36.00 doi:10.1016/j.athoracsur.2010.03.032
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Ann Thorac Surg 2010;89:1577– 81