- Email: [email protected]
Lobectomy Versus Limited Resection in T1N0 Lung Cancer
742
CORRESPONDENCE
While in no way definitive, we believe our data highlight several important points regarding lung metastasectomy for colorectal cancer that are not well addressed in the literature to date. (1) Lymph node metastases are a poor prognostic indicator overall. (2) Lymph node metastases may not be a contraindication to surgical resection. (3) CT-PET has a relatively poor sensitivity for evaluating the mediastinum for nodal metastases in the setting of lung lesions from metastatic colorectal cancer. Although these three points form only part of the equation for surgical decision making as to which patient is a candidate for metastasectomy, we believe these conclusions are an important contribution to the literature, given the scarcity of studies examining this specific subject area. Reports such as the Gonzalez metaanalysis [3] clearly identify which patients benefit most from metastasectomy, but they do not clearly identify the cutoff point as to which patients should be considered for lung metastasectomy versus those who will not achieve any added quantity or quality of life. This remains a challenging question for thoracic surgical oncologists despite the available data in the literature. Dennis A. Wigle, MD, PhD Division of Thoracic Surgery Mayo Clinic 200 First St SW Rochester, MN 55905 e-mail: [email protected]
References 1. Baisi A, De Simone M, Raveglia F, Cioffi U. Risk factors for survival in candidates for lung metastasectomy for colorectal cancer (letter). Ann Thorac Surg 2013;96:740–1. 2. Hamaji M, Cassivi SD, Shen KR, et al. Is lymph node dissection required in pulmonary metastasectomy for colorectal adenocarcinoma? Ann Thorac Surg 2012;94:1796–801. 3. Gonzalez M, Poncet A, Combescure C, Robert J, Ris HB, Gervaz P. Risk factors for survival after lung metastasectomy in colorectal cancer patients: a systematic review and metaanalysis. Ann Surg Oncol 2013;20:572–9.
Doppler Probe Is Helpful in Locating Embedded Coronary Arteries To the Editor:
MISCELLANEOUS
We read with interest the article by Aydin and Kocogullari describing a method for locating embedded left anterior descending coronary artery [1]. They reported an alternative method, intraoperative cine-angiography, to identify embedded coronary arteries. Although their technique may be helpful for this difficult situation during the operation, we almost routinely use a simple method for this purpose. In case of an intramural or embedded coronary artery, we use the X-plore Doppler probe with the Veri-Q Flowmeter System (Medistim ASA, Oslo, Norway). With this system, intramural coronary arteries can be detected by sweeping the X-plore probe across the target area. In contrast to the existing tools for intraoperative coronary anastomoses evaluation, Doppler technology will provide both functional and anatomic information on the target vessel, the graft used for revascularization, and the newly constructed anastomosis [2, 3]. A coronary artery can be identified easily by an increase in flow velocity, and it is easy to distinguish from the continuous lowvelocity venous flow. This system is also helpful for identifying coronary arteries during redo coronary bypass operations [4]. We recommend the use of a Doppler probe in such difficult situations, and we kindly invite the authors to discuss our approach. Ó 2013 by The Society of Thoracic Surgeons Published by Elsevier Inc
Ann Thorac Surg 2013;96:740–5
Volkan Yuksel, MD Serhat Huseyin, MD Hasan Sunar, MD Suat Canbaz, MD Cardiovascular Surgery Trakya University Trakya Universitesi Kalp Damar Cerrahisi Anabilim Dali Edirne, Turkey 22100 e-mail: [email protected]
References 1. Aydin U, Kocogullari CU. A method for locating embedded left anterior descending coronary arteries. Ann Thorac Surg 2013;95:360–1. 2. D’Ancona G, Hartman JM, Bartolozzi F, et al. Epicardial coronary artery Doppler: validation in the animal model. Interact Cardiovasc Thorac Surg 2008;7:634–7. 3. Stein H, Smith JM, Robinson JR, Katz MR. Target vessel detection and coronary anastomosis assessment by intraoperative 12-MHz ultrasound. Ann Thorac Surg 2006;82:1078–84. 4. Lotto AA, Owens WA. Intraoperative Doppler velocity measurements to locate patent ITA grafts at reoperation. Ann Thorac Surg 2006;82:1108–10.
Reply To the Editor: We appreciate the comments of Yuksel and colleagues [1] regarding our article [2] on locating embedded coronary arteries. They emphasize the utility of Doppler ultrasonography in such cases, and we agree. Although many studies suggest epicardial Doppler ultrasonography and intracoronary probe guidance to identify an embedded LAD in adipose tissue or myocardium, epicardial Doppler ultrasonography, which is proven reliable, requires a trained team [1]. Coronary flow cannot be detected by the Doppler method in an arrested heart after dissection for locating the artery is mostly performed. Flow is limited during this process. We agree that there should be more controlled studies on this issue. Ufuk Aydin, MD Cevdet Ugur Kocogullari, MD Department of Cardiothoracic Surgery Kocaeli Derince Training and Research Hospital Kocaeli 41900, Turkey e-mail: [email protected]
References 1. Yuksel V, Huseyin S, Sunar H, Canbaz S. Doppler probe is helpful in locating embedded coronary arteries (letter). Ann Thorac Surg 2013;96:742. 2. Aydin U, Kocogullari CU. A method for locating embedded left anterior descending coronary arteries. Ann Thorac Surg 2013;95:360–1.
Lobectomy Versus Limited Resection in T1N0 Lung Cancer To the Editor: An issue that is currently undergoing intense scrutiny is the role of sublobar resection for early-stage lung cancer. Although many nonrandomized comparisons are being performed, to date the only randomized study remains that of the Lung Cancer Study 0003-4975/$36.00
Ann Thorac Surg 2013;96:740–5
CORRESPONDENCE
743
Fig 1. Time to death (from any cause) by treatment for 247 eligible patients. (Reprinted from Rubinstein and Ginsberg, Ann Thorac Surg 1996;62:1249-50 [2], with permission.)
Group (LCSG). As a result, many articles refer to the publication of this study by Ginsberg and colleagues in 1995 [1]. However, this study contained errors that were later corrected, including survival curves, which are reproduced again here. The errors were pointed out in a letter to the editor, and the corrected data were provided in a reply by Rubinstein and Ginsberg in 1996 [2]. Unfortunately, because the correction was published as a reply to a letter, it is not searchable and has slipped for all practical purposes into oblivion. With the degree of attention directed toward the LCSG study, it is important that people are aware of and use the correct data. The primary problem with the 1995 publication was that data were inadvertently unaccounted for in almost one third of the patients. A second review of the data uncovered 12 additional recurrences and 3 additional deaths. Using the corrected data, there was a survival benefit to the lobectomy group (5-year actuarial survival, 73% versus 56%; log-rank p ¼ 0.062) and a decrease in the rate of recurrence (5-year actuarial rate of 63% versus 78%; p ¼ 0.042; see Figs 1, 2). The rate of
distant recurrences was the same in both groups, but the limited resection patients experienced a threefold higher rate of locoregional recurrence (5.4% versus 1.9% per person per year; p ¼ 0.009). In a new multivariate analysis, weight loss replaced performance status as a significant predictor of overall survival. Although the numbers, graphs, and multivariate findings changed slightly, the overall conclusions of the LCSG study were not altered by the corrected data presented by Rubinstein and Ginsburg in 1996 [2]. Nevertheless, it is important that investigators are aware of the corrected data, are able to identify this letter by an electronic search, and cite the reply letter. Frank C. Detterbeck, MD Yale University School of Medicine Division of Thoracic Surgery 330 Cedar St, BB 205 New Haven, CT 06520-8062 e-mail: [email protected]
MISCELLANEOUS
Fig 2. Time to recurrence (excluding second primaries) by treatment for 247 eligible patients. (Reprinted from Rubinstein and Ginsberg, Ann Thorac Surg 1996;62:1249-50 [2], with permission.)
744
CORRESPONDENCE
Ann Thorac Surg 2013;96:740–5
References
References
1. Ginsberg RJ, Rubinstein LV, for the Lung Cancer Study Group. Randomized trial of lobectomy versus limited resection for T1 N0 non-small cell lung cancer. Ann Thorac Surg 1995;60:615–23. 2. Rubinstein LV, Ginsberg RJ. Reply to: Lederle FA. Lobectomy versus limited resection in T1 N0 lung cancer. Ann Thorac Surg 1996;62:1249–50 [Correspondence re: Ginsberg RJ, Rubinstein LV, for the Lung Cancer Study Group. Randomized trial of lobectomy versus limited resection for T1 N0 non-small cell lung cancer. Ann Thorac Surg 1995;60:615-23].
1. Bhamidipati CM, Stukenborg GJ, Thomas CJ, et al. Pathologic lymph node ratio is a predictor of survival in esophageal cancer. Ann Thorac Surg 2012;94:1643–51. 2. Rice TW, Rusch VW, Ishwaran H, Blackstone EH. Cancer of the esophagus and esophagogastric junction: data-driven staging for the seventh Edition of the American Joint Committee on Cancer/International Union Against Cancer Staging Manuals. Cancer 2010;16:3763–73. 3. Dutkowski P, Hommel G, Bottger T, Schlick T, Junginger T. How many lymph nodes are needed for an accurate pN classification in esophageal cancer? Evidence for a new threshold value. Hepatogastroenterology 2002;49:176–80.
Lymph Node Ratio: A Confounded Quotient To the Editor:
MISCELLANEOUS
We read with interest the article by Bhamidipati and colleagues [1] concerning lymph node ratio (LNR) predicting survival of patients with esophageal cancer. Number of positive nodes (Nþ) is the strongest survival predictor, with the largest survival decrease between no Nþ and one [2]. Thereafter, the incremental decrease is small with increasing Nþ, and survival plateaus at nine Nþ. Much information is lost compressing data into N classification. Lymphadenectomy is critical in determining Nþ. Maximum increase in sensitivity occurs between zero and six resected nodes, with 90% sensitivity at 12 nodes, although sensitivity increases continuously up to 100 nodes [3]. Furthermore, lymphadenectomy and pathologic review are poorly done. The quotient LNR and its components, Nþ number (numerator) and number of nodes resected (denominator), are highly dependent on lymphadenectomy quality and pathologic review. The quotient LNR measures metastatic potential and lymphadenectomy adequacy, thus confounding cancer biology with surgical technique. The problem with quotients is that larger denominators produce smaller fractions. With LNR of 0.25, do patients with one Nþ of four resected, 4 of 16, and 10 of 40 have similar survival? Only if lymphadenectomy is inadequate and Nþ are unresected. Conversely, how can patients with one Nþ of four resected (LNR ¼ 0.25), 1 of 16 (LNR ¼ 0.063), and 1 of 40 (LNR ¼ 0.025) have significantly different survival if truly all have one Nþ? In this small, single-institution series, 61% of patients had no Nþ (LNR ¼ 0). Inclusion of these good-prognosis patients in the analyses will always make the quotient LNR a better predictor of survival than Nþ number. How would the quotient LNR perform in the analysis excluding LNR ¼ 0 patients? Further confounding the quotient LNR in this analysis is that Nþ number is included twice: as a simple variable and as a component of LNR. It is not surprising that two models did not identify Nþ number as an independent survival predictor, because it already significantly predicted survival as a component of LNR. Clinically and in our research [2], we have found the quotient LNR to be useless as a survival predictor. It is better to report Nþ number and resected node number independently, avoiding confounding of data and hobbling of prognostication.
Reply To the Editor: We appreciate Drs Rice and Blackstone [1] reviewing our article [2] and offering their thoughtful comments. We agree with their central premise that adequacy of surgical technique during lymphadenectomy and a proper pathologic review are paramount to correct diagnoses, risk stratification, and clinical management. Although these two (ie, surgery and pathology) contributing factors increase the sensitivity and specificity of detection and prognostication, the ability to consistently ensure their occurrence and reproducibility across centers is unfortunately suboptimal. Our primary objective was to examine the potential of lymph node ratio (LNR) as an independent predictor of survival in patients with esophageal cancer, and to this end we compared LNR and Nþ nodes through our modeling equations. As pointed out, surgical technique and tumor biology are indeed independent events. It is also true that a large denominator, suggesting an extensive and perhaps more complete dissection, would reduce the LNR if the total Nþ remains low. Implicit within this statement is the fact that with a complete lymph node dissection, we are more likely to identify Nþ nodes than with a less extensive lymphadenectomy. In other words, albeit possible, it is unlikely to have not resected an Nþ node in greater lymphadenectomy. Conversely, the likelihood of this happening is greater when fewer nodes are resected. With improved clinical staging methods, it is not that surprising that our series had 61% nodenegative patients. However, survival plots derived by a Cox proportional hazard model for node-positive patients in the surgical group examined by LNR interval demonstrated a survival benefit for patients with LNR <0.2 [2]. This same review in the induction group was less pronounced. We agree that clinically it is always better to report the Nþ node number and the total number of nodes resected in estimating disease risk and pathologic staging. We also agree that statistical haggling will never be a surrogate for an oncologically sound operation with an adequate lymphadenectomy. Castigliano M. Bhamidipati, DO, PhD Department of Surgery SUNY Upstate Medical University 750 E Adams St UH 8140 Syracuse, NY 13210
Thomas W. Rice, MD Eugene H. Blackstone, MD
David R. Jones, MD
Cleveland Clinic Department of Thoracic and Cardiovascular Surgery 9500 Euclid Avenue/J4-1 Cleveland, OH 44195 e-mail: [email protected]
Department of Surgery University of Virginia School of Medicine PO Box 800679 Charlottesville, VA 22908-0679 e-mail: [email protected]
Ó 2013 by The Society of Thoracic Surgeons Published by Elsevier Inc
0003-4975/$36.00
CORRESPONDENCE
While in no way definitive, we believe our data highlight several important points regarding lung metastasectomy for colorectal cancer that are not well addressed in the literature to date. (1) Lymph node metastases are a poor prognostic indicator overall. (2) Lymph node metastases may not be a contraindication to surgical resection. (3) CT-PET has a relatively poor sensitivity for evaluating the mediastinum for nodal metastases in the setting of lung lesions from metastatic colorectal cancer. Although these three points form only part of the equation for surgical decision making as to which patient is a candidate for metastasectomy, we believe these conclusions are an important contribution to the literature, given the scarcity of studies examining this specific subject area. Reports such as the Gonzalez metaanalysis [3] clearly identify which patients benefit most from metastasectomy, but they do not clearly identify the cutoff point as to which patients should be considered for lung metastasectomy versus those who will not achieve any added quantity or quality of life. This remains a challenging question for thoracic surgical oncologists despite the available data in the literature. Dennis A. Wigle, MD, PhD Division of Thoracic Surgery Mayo Clinic 200 First St SW Rochester, MN 55905 e-mail: [email protected]
References 1. Baisi A, De Simone M, Raveglia F, Cioffi U. Risk factors for survival in candidates for lung metastasectomy for colorectal cancer (letter). Ann Thorac Surg 2013;96:740–1. 2. Hamaji M, Cassivi SD, Shen KR, et al. Is lymph node dissection required in pulmonary metastasectomy for colorectal adenocarcinoma? Ann Thorac Surg 2012;94:1796–801. 3. Gonzalez M, Poncet A, Combescure C, Robert J, Ris HB, Gervaz P. Risk factors for survival after lung metastasectomy in colorectal cancer patients: a systematic review and metaanalysis. Ann Surg Oncol 2013;20:572–9.
Doppler Probe Is Helpful in Locating Embedded Coronary Arteries To the Editor:
MISCELLANEOUS
We read with interest the article by Aydin and Kocogullari describing a method for locating embedded left anterior descending coronary artery [1]. They reported an alternative method, intraoperative cine-angiography, to identify embedded coronary arteries. Although their technique may be helpful for this difficult situation during the operation, we almost routinely use a simple method for this purpose. In case of an intramural or embedded coronary artery, we use the X-plore Doppler probe with the Veri-Q Flowmeter System (Medistim ASA, Oslo, Norway). With this system, intramural coronary arteries can be detected by sweeping the X-plore probe across the target area. In contrast to the existing tools for intraoperative coronary anastomoses evaluation, Doppler technology will provide both functional and anatomic information on the target vessel, the graft used for revascularization, and the newly constructed anastomosis [2, 3]. A coronary artery can be identified easily by an increase in flow velocity, and it is easy to distinguish from the continuous lowvelocity venous flow. This system is also helpful for identifying coronary arteries during redo coronary bypass operations [4]. We recommend the use of a Doppler probe in such difficult situations, and we kindly invite the authors to discuss our approach. Ó 2013 by The Society of Thoracic Surgeons Published by Elsevier Inc
Ann Thorac Surg 2013;96:740–5
Volkan Yuksel, MD Serhat Huseyin, MD Hasan Sunar, MD Suat Canbaz, MD Cardiovascular Surgery Trakya University Trakya Universitesi Kalp Damar Cerrahisi Anabilim Dali Edirne, Turkey 22100 e-mail: [email protected]
References 1. Aydin U, Kocogullari CU. A method for locating embedded left anterior descending coronary arteries. Ann Thorac Surg 2013;95:360–1. 2. D’Ancona G, Hartman JM, Bartolozzi F, et al. Epicardial coronary artery Doppler: validation in the animal model. Interact Cardiovasc Thorac Surg 2008;7:634–7. 3. Stein H, Smith JM, Robinson JR, Katz MR. Target vessel detection and coronary anastomosis assessment by intraoperative 12-MHz ultrasound. Ann Thorac Surg 2006;82:1078–84. 4. Lotto AA, Owens WA. Intraoperative Doppler velocity measurements to locate patent ITA grafts at reoperation. Ann Thorac Surg 2006;82:1108–10.
Reply To the Editor: We appreciate the comments of Yuksel and colleagues [1] regarding our article [2] on locating embedded coronary arteries. They emphasize the utility of Doppler ultrasonography in such cases, and we agree. Although many studies suggest epicardial Doppler ultrasonography and intracoronary probe guidance to identify an embedded LAD in adipose tissue or myocardium, epicardial Doppler ultrasonography, which is proven reliable, requires a trained team [1]. Coronary flow cannot be detected by the Doppler method in an arrested heart after dissection for locating the artery is mostly performed. Flow is limited during this process. We agree that there should be more controlled studies on this issue. Ufuk Aydin, MD Cevdet Ugur Kocogullari, MD Department of Cardiothoracic Surgery Kocaeli Derince Training and Research Hospital Kocaeli 41900, Turkey e-mail: [email protected]
References 1. Yuksel V, Huseyin S, Sunar H, Canbaz S. Doppler probe is helpful in locating embedded coronary arteries (letter). Ann Thorac Surg 2013;96:742. 2. Aydin U, Kocogullari CU. A method for locating embedded left anterior descending coronary arteries. Ann Thorac Surg 2013;95:360–1.
Lobectomy Versus Limited Resection in T1N0 Lung Cancer To the Editor: An issue that is currently undergoing intense scrutiny is the role of sublobar resection for early-stage lung cancer. Although many nonrandomized comparisons are being performed, to date the only randomized study remains that of the Lung Cancer Study 0003-4975/$36.00
Ann Thorac Surg 2013;96:740–5
CORRESPONDENCE
743
Fig 1. Time to death (from any cause) by treatment for 247 eligible patients. (Reprinted from Rubinstein and Ginsberg, Ann Thorac Surg 1996;62:1249-50 [2], with permission.)
Group (LCSG). As a result, many articles refer to the publication of this study by Ginsberg and colleagues in 1995 [1]. However, this study contained errors that were later corrected, including survival curves, which are reproduced again here. The errors were pointed out in a letter to the editor, and the corrected data were provided in a reply by Rubinstein and Ginsberg in 1996 [2]. Unfortunately, because the correction was published as a reply to a letter, it is not searchable and has slipped for all practical purposes into oblivion. With the degree of attention directed toward the LCSG study, it is important that people are aware of and use the correct data. The primary problem with the 1995 publication was that data were inadvertently unaccounted for in almost one third of the patients. A second review of the data uncovered 12 additional recurrences and 3 additional deaths. Using the corrected data, there was a survival benefit to the lobectomy group (5-year actuarial survival, 73% versus 56%; log-rank p ¼ 0.062) and a decrease in the rate of recurrence (5-year actuarial rate of 63% versus 78%; p ¼ 0.042; see Figs 1, 2). The rate of
distant recurrences was the same in both groups, but the limited resection patients experienced a threefold higher rate of locoregional recurrence (5.4% versus 1.9% per person per year; p ¼ 0.009). In a new multivariate analysis, weight loss replaced performance status as a significant predictor of overall survival. Although the numbers, graphs, and multivariate findings changed slightly, the overall conclusions of the LCSG study were not altered by the corrected data presented by Rubinstein and Ginsburg in 1996 [2]. Nevertheless, it is important that investigators are aware of the corrected data, are able to identify this letter by an electronic search, and cite the reply letter. Frank C. Detterbeck, MD Yale University School of Medicine Division of Thoracic Surgery 330 Cedar St, BB 205 New Haven, CT 06520-8062 e-mail: [email protected]
MISCELLANEOUS
Fig 2. Time to recurrence (excluding second primaries) by treatment for 247 eligible patients. (Reprinted from Rubinstein and Ginsberg, Ann Thorac Surg 1996;62:1249-50 [2], with permission.)
744
CORRESPONDENCE
Ann Thorac Surg 2013;96:740–5
References
References
1. Ginsberg RJ, Rubinstein LV, for the Lung Cancer Study Group. Randomized trial of lobectomy versus limited resection for T1 N0 non-small cell lung cancer. Ann Thorac Surg 1995;60:615–23. 2. Rubinstein LV, Ginsberg RJ. Reply to: Lederle FA. Lobectomy versus limited resection in T1 N0 lung cancer. Ann Thorac Surg 1996;62:1249–50 [Correspondence re: Ginsberg RJ, Rubinstein LV, for the Lung Cancer Study Group. Randomized trial of lobectomy versus limited resection for T1 N0 non-small cell lung cancer. Ann Thorac Surg 1995;60:615-23].
1. Bhamidipati CM, Stukenborg GJ, Thomas CJ, et al. Pathologic lymph node ratio is a predictor of survival in esophageal cancer. Ann Thorac Surg 2012;94:1643–51. 2. Rice TW, Rusch VW, Ishwaran H, Blackstone EH. Cancer of the esophagus and esophagogastric junction: data-driven staging for the seventh Edition of the American Joint Committee on Cancer/International Union Against Cancer Staging Manuals. Cancer 2010;16:3763–73. 3. Dutkowski P, Hommel G, Bottger T, Schlick T, Junginger T. How many lymph nodes are needed for an accurate pN classification in esophageal cancer? Evidence for a new threshold value. Hepatogastroenterology 2002;49:176–80.
Lymph Node Ratio: A Confounded Quotient To the Editor:
MISCELLANEOUS
We read with interest the article by Bhamidipati and colleagues [1] concerning lymph node ratio (LNR) predicting survival of patients with esophageal cancer. Number of positive nodes (Nþ) is the strongest survival predictor, with the largest survival decrease between no Nþ and one [2]. Thereafter, the incremental decrease is small with increasing Nþ, and survival plateaus at nine Nþ. Much information is lost compressing data into N classification. Lymphadenectomy is critical in determining Nþ. Maximum increase in sensitivity occurs between zero and six resected nodes, with 90% sensitivity at 12 nodes, although sensitivity increases continuously up to 100 nodes [3]. Furthermore, lymphadenectomy and pathologic review are poorly done. The quotient LNR and its components, Nþ number (numerator) and number of nodes resected (denominator), are highly dependent on lymphadenectomy quality and pathologic review. The quotient LNR measures metastatic potential and lymphadenectomy adequacy, thus confounding cancer biology with surgical technique. The problem with quotients is that larger denominators produce smaller fractions. With LNR of 0.25, do patients with one Nþ of four resected, 4 of 16, and 10 of 40 have similar survival? Only if lymphadenectomy is inadequate and Nþ are unresected. Conversely, how can patients with one Nþ of four resected (LNR ¼ 0.25), 1 of 16 (LNR ¼ 0.063), and 1 of 40 (LNR ¼ 0.025) have significantly different survival if truly all have one Nþ? In this small, single-institution series, 61% of patients had no Nþ (LNR ¼ 0). Inclusion of these good-prognosis patients in the analyses will always make the quotient LNR a better predictor of survival than Nþ number. How would the quotient LNR perform in the analysis excluding LNR ¼ 0 patients? Further confounding the quotient LNR in this analysis is that Nþ number is included twice: as a simple variable and as a component of LNR. It is not surprising that two models did not identify Nþ number as an independent survival predictor, because it already significantly predicted survival as a component of LNR. Clinically and in our research [2], we have found the quotient LNR to be useless as a survival predictor. It is better to report Nþ number and resected node number independently, avoiding confounding of data and hobbling of prognostication.
Reply To the Editor: We appreciate Drs Rice and Blackstone [1] reviewing our article [2] and offering their thoughtful comments. We agree with their central premise that adequacy of surgical technique during lymphadenectomy and a proper pathologic review are paramount to correct diagnoses, risk stratification, and clinical management. Although these two (ie, surgery and pathology) contributing factors increase the sensitivity and specificity of detection and prognostication, the ability to consistently ensure their occurrence and reproducibility across centers is unfortunately suboptimal. Our primary objective was to examine the potential of lymph node ratio (LNR) as an independent predictor of survival in patients with esophageal cancer, and to this end we compared LNR and Nþ nodes through our modeling equations. As pointed out, surgical technique and tumor biology are indeed independent events. It is also true that a large denominator, suggesting an extensive and perhaps more complete dissection, would reduce the LNR if the total Nþ remains low. Implicit within this statement is the fact that with a complete lymph node dissection, we are more likely to identify Nþ nodes than with a less extensive lymphadenectomy. In other words, albeit possible, it is unlikely to have not resected an Nþ node in greater lymphadenectomy. Conversely, the likelihood of this happening is greater when fewer nodes are resected. With improved clinical staging methods, it is not that surprising that our series had 61% nodenegative patients. However, survival plots derived by a Cox proportional hazard model for node-positive patients in the surgical group examined by LNR interval demonstrated a survival benefit for patients with LNR <0.2 [2]. This same review in the induction group was less pronounced. We agree that clinically it is always better to report the Nþ node number and the total number of nodes resected in estimating disease risk and pathologic staging. We also agree that statistical haggling will never be a surrogate for an oncologically sound operation with an adequate lymphadenectomy. Castigliano M. Bhamidipati, DO, PhD Department of Surgery SUNY Upstate Medical University 750 E Adams St UH 8140 Syracuse, NY 13210
Thomas W. Rice, MD Eugene H. Blackstone, MD
David R. Jones, MD
Cleveland Clinic Department of Thoracic and Cardiovascular Surgery 9500 Euclid Avenue/J4-1 Cleveland, OH 44195 e-mail: [email protected]
Department of Surgery University of Virginia School of Medicine PO Box 800679 Charlottesville, VA 22908-0679 e-mail: [email protected]
Ó 2013 by The Society of Thoracic Surgeons Published by Elsevier Inc
0003-4975/$36.00