cytologically proven or suspected lung cancer: a VATS exploration

LUNG CANCER ELSEVIER

Lung Cancer 16 (1997) 183-190

Thoracoscopic evaluation of histologically/cytologically proven or suspected lung cancer: a VATS exploration Hisao Asamura *, Haruhiko Nakayama, Haruhiko Ryosuke Tsuchiya, Tsuguo Naruke Division

qj Thoracic

Surgery,

National

Cancer Center Hospital Tokyo 104, Japan

Japan.

1- 1, Tsukiji

Kondo, 5-chome,

Chuo-ku,

Received 14 August 1996; received in revised form 8 November 1996; accepted 19 November 1996

Abstract To evaluate the diagnostic value of video-assisted thoracic surgery (VATS), VATS exploration was performed in 135 patients with histologically/cytologically proven or suspected lung cancer. In 31 patients with pulmonary nodules suspected to be lung cancer. VATS exploration was intended to determine their histology by wedge resection. A histological diagnosis was made in all of the patients: 12 lung cancers (38.7”/0), 12 inflammatory granulomas (38.7%). four hamartomas (12.90/o), and three others. VATS exploration (staging) was performed in 116 surgical candidates with documented lung cancer, including the 12 patients diagnosed by VATS wedge resection. Inoperable factors were demonstrated by this procedure in five patients (4.3%): malignant effusion without dissemination in three, malignant effusion with extensive dissemination in one, and extensive dissemination without effusion in one. Furthermore, N2 nodal metastasis at Botallo’s ligament was demonstrated by this procedure in two patients. which met the eligibility criteria for a clinical study. Although the documented number of patients was relatively small, VATS exploration obviated the need for painful thoracotomy, selecting better treatment and for evaluating eligibility criteria for prospective clinical trials. The results suggest that this procedure is useful in candidates for lung cancer surgery. 0 1997 Elsevier Science Ireland Ltd.

* Corresponding author. Tel: + 81 3 35422511; fax: + 81 3 35453567. 0169.5002/97/$17.00 0 1997 Elsevier Science Ireland Ltd. All rights reserved. PII SO169-5002(96)00628-9

184 Keywords:

H. Asamum

Video-assisted

thoracic

et al. /Lung

surgery;

Cancer

16 (19971

Thoracoscopic

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surgery;

Lung cancer; Staging;

Diagnosis

1. Introduction Video-assisted thoracic surgery (VATS) is playing an increasingly important role in the diagnosis and treatment of various diseasesin the thorax [2,5,6,8]. However, the role of videothoracoscopy in the management of lung cancer has not yet been clearly defined, and its clinical significance is controversial [1,10,12]. Thoracoscopy has two distinct roles; i.e. as a diagnostic tool and as a therapeutic tool in surgery. The former role is referred to as exploratory thoracoscopy or VATS exploration, and the latter role is called therapeutic VATS. Although the feasibility of major pulmonary resection by VATS (therapeutic VATS) has been aggressively assessedby several surgeons [4,7,9,11], the diagnostic usefulness of VATS exploration has not been fully documented. There are at least two main objectives in VATS exploration in the management of lung cancer. One is to make a definitive histologic or cytologic diagnosis for suspected lung cancer of undetermined histology. The second purpose is to make a final and ultimate evaluation of resectability in candidates for lung cancer surgery, which entails staging and the detection of unresectable or inoperable factors. However, the clinical significance of VATS exploration must be clearly documented for it to be established as a routine diagnostic method for lung cancer. This preliminary study assessedthe efficacy of VATS exploration for lung cancer based on our previous experience.

2. Material and methods 2.1. Putirnts

At the National Cancer Center Hospital, Tokyo, we performed VATS exploration in 135 patients from January 1995 through January 1996. Of these patients, 31 patients underwent VATS exploration for the establishment of histological diagnosis, since neither percutaneous fine needle aspiration biopsy nor bronchoscopic biopsy could demonstrate definite histology. The rest of the patients had been previously diagnosed cytologically or histologically as lung cancer (Table l), and underwent VATS exploration as a preoperative evaluation for resectability. Patients who had squamous cell carcinoma at the pulmonary hilum in the relatively early stageswere excluded from VATS exploration, since squamous cell carcinoma generally had little possibility of pleural implantation to cause carcinomatous pleurisy. In this preliminary setting, all the patients, in whom the thoracoscopic

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equipment was available and the informed consent was given, underwent VATS exploration. These patients comprised 56% of all of the candidates for surgical resection for lung cancer during this period.

2.2.

Technique

A VATS exploration was performed with the patient in a standard lateral decubitus position, with single-lung ventilation using double-lumen endotracheal intubation tube (Mallinkrodt Medical, Athlone, Ireland). Two access trocars were usually placed for this procedure. An additional trocar was placed only when wedge resection was indicated. After the affected lung was completely deflated, a 0” or 30” rigid thoracoscope (Olympus Co., Tokyo, Japan) was inserted from the first trocar site in the 7th intercostal space on the midaxillary line. The second trocar was just at the anterior edge of the scheduled incisional posterolateral thoracotomy line in the 4th or 5th intercostal space (Fig. 1). Even if the patient underwent thoracotomy, since the chest tube was inserted through the first trocar incision and the second trocar was just on the thoracotomy incisional line, the patient usually did not have an additional wound due to this procedure. To allow for the full and sequential inspection of the pleural space, especially at the upper, anterior, posterior, and lower mediastinum, at the hilum, and of the tumor lesion itself, the collapsed lung was retracted with a Cottonfinger@ dissector (Kenzmedico Co., Kodama, Japan). If there were small nodules on the pleural surface which suggested pleural implantation, a biopsy specimen was taken with biopsy forceps. Pleural effusion was routinely characterized grossly and aspirated for rapid cytological examination regardless of its amount. Mediastinal lymph nodes, if swollen, were also biopsied, especially at Botallo’s and subcarinal locations because of the difficulty of accessing this site by mediastinoscopy. For nodules of undetermined histology, wedge resection with endstaplers (EndoGIAm, US Surgical Corp., Norwalk, CT) was performed. The resected specimen was immediately submitted for rapid pathological diagnosis.

Table VATS

1 exploration

Objectives

of VATS

for histologically/cytologically

proven

exploration

12 patients

diagnosed

lung cancer

No. of patients

Determination of histology Staging of lung cancer Total *Includes

or suspected

31 116* 135 by VATS

wedge

resection

186

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Cmcrr

1st Zrocar

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I 1 /

Fig. 1. Placement of access ports in VATS exploration for lung cancer: first trocar. 7th intercostal space on the midaxillary line; second trocar, at the anterior edge of the thoracotomy line in the 4th or 5th intercostal space. The shaded line indicates the scheduled thoracotomy incision.

3. Results 3.1. VATS exploration

for nodules of unkno~w

histolog!)

VATS exploration was performed in 31 patients with pulmonary nodules of suspected lung cancer to determine their histology by wedge resection. Histology was determined in all of the cases by this procedure (Table 2). Twelve patients with lung cancer (38.7%) subsequently underwent further pulmonary resection; under video-assisted guidance in three and conventional open thoracotomy in nine. None of the 19 patients without lung cancer required further thoracotomy. The lymphatic apparatus in Table 2 refers to the intrapulmonary lymphoid tissue without a basic encapsulated nodal structure.

H. Asarnwu Table 2 VATS exploration

for suspected

rr al. /Lung

lung cancer

Caner

16 (1997)

of undetermined

No.

Lung cancer* Miscellaneous Fibrosis or granulation Hamartoma Metastasis Localized mesothelioma Lymphatic apparatus Total

12 19 I2 4 I 1 1 31

underwent

3.2. VATS exploration

VATS

187

histology

Histology

*Subsequently

183-190

points

staging.

,for final pretreatment

staging

VATS exploration (staging) was performed for 116 surgical candidates with documented lung cancer, including 12 patients who were initially diagnosed by VATS wedge resection. These patients comprised 56% of all of the candidates for surgical resection for lung cancer during this period. There were no complications or operative deaths related to the VATS exploration. The results of assessing each TNM-related factor as well as the clinical course were as follows. 3.2.1. Pleural effusioil No pleural effusion was found in 63 patients (54.3%). In the remaining 53 patients (46.7%). effusion was clearly demonstrated on the thoracoscopic images. Although the amount of serous effusion was minimal, in most instances (less than 5 ml), samples were aspirated and submitted for rapid cytological examination. In five patients (4.3%), a cytological examination revealed the cancer cells, and the tumor was categorized as T4. Based on these results, four patients did not undergo thoracotomy. In one patient, since there were so few cancer cells in a small amount of fluid (less than 1 ml), lobectomy was performed for fear of cytological overdiagnosis. 3.2.2. Pleural dissemination In three patients (2.7%), disseminated minute nodules were observed on the pleural surface, which were all biopsied and diagnosed histologically. Of these three patients, only one patient had cytologically-positive effusion. Preoperatively, one patient had no roentgenological sign which was suggestive of pleural implant of the tumor, while other two had equivocal thickening of the pleural surface without accumulation of effusion on chest CT. Two patients with extensive dissemination were considered inoperable. One patient with less-extensive implantation subsequently underwent pleuropneumonectomy after informed consent was given.

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H. Asamura

Table 3 Inoperable

factors

Inoperable

factor

found

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in three

patients

with

at thoracotomy

Contralateral hilar lymph node metastasis Aortic and esophageal invasion

183-190

previous

VATS No.

(N3)

exploration

points

2 1

3.2.3. Nodal sampling Thoracoscopic biopsy was performed in two patients (1.7%) in whom chest CT scan demonstrated swelling of the subaortic nodes. Since N2 disease was confirmed histologically, these patients entered a clinical trial of induction chemotherapy followed by surgery. Hilar node biopsy was not attempted in this series of patients. 3.2.4. Clinical course of patients undergoing VATS exploration Further thoracotomy was not performed in five patients (4.3%) due to minimal amount of malignant effusion in four patients (three without dissemination and one with dissemination) and extensive dissemination without malignant effusion in one. In three patients (2.6%) VATS exploration was used to assess eligibility for a clinical trial: i.e. for the definite diagnosis of N2 disease with nodal metastasis at the subaorta in two patients and to exclude suspected pleural dissemination in one patient with already proven N2 disease by mediastinoscopy. Consequently, 110 patients (94.8%) underwent open thoracotomy. Despite the recent VATS exploration, three patients (2.6%) were found to have unresectable factors (Table 3). The other 107 patients (92.2%) subsequently undergo pulmonary resection.

4. Discussion VATS has unique features as a diagnostic method that other methods, such as mediastinoscopy and bronchoscopy, lack. Its most outstanding feature is that it is the only one modality that allows for the complete visualization of the pleural space. This is especially important if pleural dissemination or small amount of effusion is suspected on CT scan. In addition, VATS can allow for various interventional procedures: i.e. biopsy of the suspected pleural lesion and swollen lymph node and aspiration of a small amount of effusion. Finally, VATS exploration is safe enough to be performed in basically every surgical candidate except for those with extensive adhesion or markedly reduced pulmonary function who cannot tolerate single-lung ventilation. Furthermore, little time is required for VATS exploration. The identification of inoperable factors which cannot be found by routine check-up is clearly a significant benefit to the patient, since painful thoracotomy can be avoided. The rate of exploration by thoracotomy in our series of lung cancer surgery before the introduction of VATS exploration was 7.9% in recent 4 years (56 exploration among 711 thoracotomies), despite careful evaluation by CT scan

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preoperatively. Furthermore, a more accurate pretreatment evaluation should lead to a better choice of treatment for the patient. Lymph node biopsy at the subaortic or paraaortic location (N2) in tumors on the left side is greatly simplified by VATS exploration, although a special mediastinoscopic technique can also access these sites [3]. This feature is particularly important, when we consider candidates for induction therapy among cN2 patients. Reports of VATS staging and evaluation for lung cancer are still limited. Therefore, it is difficult to determine the percentage of the patients in whom open thordcotomy could be avoided based on the results of VATS exploration. According to Wait-r’s report [13], two (4.7%) of 43 patients with VATS staging showed unexpected pleural dissemination, obviating further surgery. Roviaro [ 121 noted that 13 (8.3%) of 155 patients undergoing videothoracoscopic exploration were inoperable for the following reasons: pleural dissemination without effusion in seven, invasion of the mediastinum in four, partial invasion of the esophageal wall in one, and tumor invasion of the artery in the fissure in one. Considering results (4.3% inoperable) and those of previous reports, the estimated percentage appear to be close to 5%. Although 5% is not particularly remarkable, this is still a benefit of VATS exploration. Furthermore, as with three patients in our series who entered a clinical trial, VATS exploration may play an important role in evaluating the eligibility criteria for study entry.

5. Conclusion Although the documented number of patients with benefit was not large, VATS exploration obviated the need for painful thoracotomy, and was useful for selecting better treatment, and for evaluating eligibility criteria for prospective clinical trials. We think that it is worthwhile for every candidate for lung cancer surgery to undergo VATS exploration before thoracotomy is performed. To more clearly determine the benefits of VATS exploration, another prospective study is underway at our institute. This prospective data will provide a more precise estimate of the percentage of patients who could benefit from this new approach.

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