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Ann Thorac Surg 1996;62:1237-1239
© 1996 The Society of Thoracic Surgeons
University of Padova, Clinica Chirurgica I, Via Giustiniani 2, 35128 Padova, Italy
To the Editor:
It was a real pleasure to read the prospective, multiinstitutional trial on thoracoscopic staging of esophageal cancer by Krasna and colleagues [1], as this topic is still debated and fascinating. Realistic preoperative staging of cancer of the intrathoracic esophagus is desirable, and it can be obtained in about 80% of patients. Krasna and colleagues aimed to improve these results by performing (in addition to the computed tomography, magnetic resonance imaging, and endosonography) preoperative thoracoscopy. They considered 49 patients and only 33 (67%) underwent surgical resection. In only 2 patients (6%) node metastases were diagnosed during thoracoscopy and in 3 more patients (or 4 as reported in the discussion?) after thoracotomy. Therefore only 40% (or 33%) of patients with node metastases were correctly staged. Positive and negative predictive values are correlated to the prevalence of node metastases, which is only 15% in this group of patients; consequently, these results should not be highlighted. Unfortunately, no data are reported about the pathologic T stage, and it is difficult to have an idea of the real prevalence of node metastases as a direct correlation between the degree of wall penetration and node metastases is acknowledged. However, a prevalence of 15% node metastases has to be considered too low even if Krasna and colleagues "believe that this is a real finding because all patients had a complete lymphadenectomy at resection" [1].
What is a complete lymphadenectomy for Dr Krasna and colleagues? How many nodes did they collect in the mediastinum? Do they think it is possible to perform a complete lymphadenectomy through a left thoracotomy, as they did in several instances? More nodes examined means more positive nodes. Siewert and Roder [2] reported a prevalence of 53.6% of metastatic nodes when fewer than 20 nodes were examined and 70.4% when more than 20 nodes were examined. We [3] demonstrated a 51.6% metastatic node rate after a standard or limited lymphadenectomy and a 65% rate after a lymphadenectomy extended to all the various mediastinal areas of esophageal lymphatic drainage that can be reached safely only through a thoracotomy.
Lymphadenectomy for cancer of the thoracic esophagus is more difficult to perform than for other cancers of the gastrointestinal tract. This is especially true in the upper mediastinum, where node dissection is very demanding to avoid recurrent nerve lesions, particularly with the esophagus in place. Above all, when exploring the left paratracheal node or left recurrent nerve chain, the trachea has to be displaced anteriorly and the esophagus posteriorly. The left recurrent nerve has to be identified and damage to it avoided. This is not always easy through a large thoracotomy. What can be said about the aortopulmonary window? When operating through right-sided access, this area is located under the esophagus, below the aortic arch, superior to the left main bronchus and above the right main pulmonary artery. These anatomic structures are very delicate, and damage to them is extremely dangerous. It is difficult for me to understand how it is possible to explore correctly these areas thoracoscopically. Just sampling or performing biopsy of a few superficial nodes should not be advocated as the way to perform the best staging of a cancer. This procedure can only let us know the status of that node we sampled, and if it is not involved, we cannot exclude that other nodes in other areas are not involved. Moreover, if a node is sampled and not completely removed, we can possibly provoke dissemination of cancer cells in the pleural or abdominal cavity.
If Krasna and colleagues' purpose is to decide a better allocation of preoperative chemotherapy or radiotherapy, then computed tomography, endosonography, and bronchoscopy for cancers located in the upper esophagus can be sufficient. In a recent article by Peters and associates [4], endosonography predicted node metastases in 82% of patients with an esophageal cancer. Krasna and colleagues' conclusions seem to be too optimistic and do not correlate with the data reported.
Last but not least, do Krasna and associates suggest one should substitute as staging procedure the computed tomography, the esophageal ultrasound, and magnetic resonance imaging with the thoracoscopic staging, or will they add an invasive, even minimally invasive, thoracoscopy that requires at least 2 hours 50 minutes to be completed to the above-mentioned noninvasive procedures? If the second hypothesis is true, the problem of cost increasing for staging an esophageal cancer has to be considered along with patient compliance, as 8 of them refused surgical resection after having experienced thoracoscopy.
References
Division of Thoracic Surgery, The University of Maryland Medical Center, Box 167, 22 S Greene St, Rm N4w87 Baltimore, MD 21201
To the Editor:
My colleagues and I thank Dr Bardini for his comments and recognize his contribution to the literature of esophageal cancer. Most importantly, we agree on the importance of lymph node staging for esophageal cancer. Although the incidence of lymph node metastasis was low in this particular series, we have recently noticed a trend to a higher incidence of T1 N0 patients at our institution.
We did not perform a routine en bloc or radical lymphadenectomy; rather, a lymph node dissection was done at all esophagectomy operations. Our goal in lymph node dissection for esophageal cancer is not to affect the survival but rather to determine the prognosis of patients with esophageal cancer. Although other authors [1–3] have described excellent results using operation with radical lymphadenectomy as a curative goal, the majority of surgical reports in the literature emphasize that operation alone with lymphadenectomy will not affect the survival. We do not, however, take a nihilistic approach toward the treatment of esophageal cancer but strongly recommend using the information of the lymph node stage to decide whether or not chemotherapy and radiation should be undertaken.
We would recommend computed tomography and esophageal ultrasound routinely in the "nontrial" setting. If nodes are seen, thoracoscopy can be performed to document N1 disease, as is done with mediastinoscopy in lung cancer. With this in mind, we would propose that once the efficacy of lymph node sampling for esophageal cancer is established, this information can then be used preoperatively. Just as in the case of mediastinoscopy for lung cancer, which is associated with a 15% false-negative rate, the information on those who do have positive lymph nodes is important in allocating patients to neoadjuvant therapy, together with possible lung resection. We see the future of esophageal cancer treatment becoming "stage specific" with treatment regimens geared toward appropriate stages as determined by lymph node status. Of note is a recent report, presented to The American Association for Thoracic Surgery by Akaishi and colleagues [4]. In this report, 30 patients with esophageal cancer underwent thoracoscopic radical lymphadenectomy in preparation for a combined laparotomy and neck anastomosis. Although the main goal of this series was to show the efficacy of thoracoscopic lymphadenectomy, it clearly highlights the ability of thoracoscopy to perform biopsy of lymph nodes in the mediastinum.
Although the lymph node yield in our series is low, it should not discourage other investigators from attempting thoracoscopic staging in esophageal cancer. If we are ever to improve the survival in these patients, we must develop treatment strategies that are stage-specific based on the prognostic indicators that Dr Bardini has mentioned. We thank him for his excellent comments on this article.
References
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