Critical Reviews in Oncology/Hematology 95 (2015) 105–113
Thoracoscopic resection of pulmonary metastasis: Current practice and results Jean Yannis Perentes a , Thorsten Krueger a , Alban Lovis b , Hans-Beat Ris a , Michel Gonzalez a,∗ a
Division of Thoracic Surgery Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland Division of Pneumonology Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
b
Received 11 August 2014; received in revised form 23 January 2015; accepted 10 February 2015
Contents 1. 2.
3.
4.
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rationale for VATS resection of solitary lung metastasis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1. Advantages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2. Inconvenients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3. Controversies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Long term results of VATS for the management of lung metastasis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1. Studies comparing VATS vs. Open thoracotomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2. Single center studies with VATS metastasectomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3. VATS approach for repeated metastasectomy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4. Hybrid procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conflict of interest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Funding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Biographies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
106 106 106 107 107 108 108 110 111 111 111 112 112 112 113
Abstract Video-assisted thoracoscopic surgery (VATS) is currently a routinely performed procedure for the management of early non small cell lung cancer. The oncological results of VATS in terms of local recurrence and overall survival are equivalent or superior to those of conventional thoracotomy with lower morbidity and hospital stay. In the field of pulmonary metastasectomy, current guidelines support a thoracotomy approach in order to properly palpate the lung and detect nodules too small to be identified on standard radiological examinations (typically less than 5 mm in diameter). However, the oncological and clinical significance of these millimetric nodules is not known. This has led some thoracic surgeons to rethink the approach of solitary pulmonary metastasectomy: because of improvements in thin slice helical CT-scans, some support a VATS approach for solitary pulmonary nodules without formal bimanual palpation and suggest this allows equivalent oncological results and decreased surgical morbidity. © 2015 Elsevier Ireland Ltd. All rights reserved.
Keywords: Video-assisted thoracoscopic surgery; Pulmonary metastasectomy
∗ Correspondence to: Division of Thoracic and Vascular Surgery Centre Hospitalier Universitaire Vaudois Rue du Bugnon 46, 1011 Lausanne/Switzerland Tel.: +41 21 314 24 08; fax: +41 21 314 23 58. E-mail address: [email protected] (M. Gonzalez).
http://dx.doi.org/10.1016/j.critrevonc.2015.02.005 1040-8428/© 2015 Elsevier Ireland Ltd. All rights reserved.
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J.Y. Perentes et al. / Critical Reviews in Oncology/Hematology 95 (2015) 105–113
1. Introduction Approximately 30% of patients suffering from malignant solid tumors will develop pulmonary metastases [1]. Efficient chemotherapy is generally unavailable for most of these tumors. Currently, it is thought that a substantial group of patients with pulmonary metastases may benefit from the resection of lung metastasis. Although there are no prospective randomized studies comparing pulmonary metastasectomy with chemotherapy or observation, surgical resection of pulmonary metastases is nowadays widely performed in selected patients [2]. Several retrospective studies have suggested an increased survival for patients who underwent complete resection of lung metastases in comparison to historical series of patients who did not benefit from lung metastasectomy [3–6]. The largest multicentric study based on the International Registry of Lung Metastases reviewed 5206 patients from 18 centers (USA, Canada and Europe) retrospectively. Complete resection was achieved in 88% of patients and was an important prognostic factor for survival: the 5-year overall survival was of 36% in patients with complete resection compared to 13% in patients with incomplete resection [3]. These results supported that pulmonary metastasectomy offered a survival advantage when complete resection was achievable. Over the past two decades, several studies have supported the role of pulmonary metastasectomy in different tumors types with a 5-year survival rate ranging from 20% to 80% depending on the primary tumor type [7,8]. The improvement of surgical techniques (video assisted thoracoscopic surgery, VATS), radiological imaging (thin slices helical CT-scan), more frequent use of PET-CT and advances with new chemotherapeutic agents have contributed to increase the number of pulmonary metastasectomy procedures and enhance the survival of metastatic patients. The established criteria for lung metastasectomy are [8]: (1) a controlled or controllable primary tumor with no evidence of active disease; (2) the absence of extra-thoracic metastatic disease. However, involvement of other extrathoracic sites may not be a contraindication to the resection of the pulmonary disease if all metastatic sites can be resected completely before the lung resection; (3) complete resection of lung metastasis must be achievable; (4) the patient has sufficient pulmonary and cardiovascular functional reserves to tolerate pulmonary resection; (5) there is no valid alternative therapy. Despite this aggressive strategy, series report up to 50% of patients with local or distant metastatic relapse [3]. The metastasis process is a highly debated and studied topic. Of the multiple theories reported to date, two major metastasis concepts are described and could have an influence in the clinical approach of lung metastasectomy [9]. A first theory suggests a late dissemination of metastasis from the primary tumor after the latter and surrounding environment have acquired sufficient genetic changes for migration and distant implementation function acquisition [10]. A second theory suggests that dissemination occurs very early in the cancer process (sometimes at the pre-malignant stage) and
that single dormant cells can but will not necessarily develop into proper metastasis following genetic and environmental alterations [11]. These theories could occur separately in different tumor types/individuals or may occur together in a same patient. The surgical metastasectomy approach is compatible with a late dissemination process if the five criteria described above are fulfilled. However, in case of an early dissemination process theory, surgical metastasectomy may not be able to achieve complete metastatic resection as premetastatic niches are too small to be palpated. Therefore, a resection approach with surveillance and possibility to redo resection should be favored in this case. Since 1990s, the VATS approach has progressively gained acceptance initially for many basic procedures such as pleural pathologies (pleural biopsy, empyema) and non-anatomical resection for benign diseases (lung biopsies, management of pneumothorax). With growing experience and advances in instrumentation, many surgeons are now routinely performing anatomical lung resections by thoracoscopy with identical standards to those obtained by open thoracotomy. Recently, the American College of Chest Physicians (ACCP) stated in their guidelines that VATS should be preferred over thoracotomy for early lung cancer in experienced centers [12]. However, controversy still exists for the utility of VATS in the resection of isolated pulmonary metastases. While this approach seems to be favored by most thoracic surgeons, there are currently no prospective randomized studies comparing the VATS approach with standard thoracotomy for the resection of lung metastases. VATS is still considered by the European Society of Thoracic Surgery (ESTS) working group for lung metastasectomy as a diagnostic but non therapeutic tool for the management of lung metastases [13]. However, recent thin slice CT scans allow a better spatial resolution and seem to achieve a level of metastasis detection comparable to a bimanual palpation [14]. In addition, several surgical studies have reported solitary pulmonary metastasis in a majority of patients (60–70%). Thus, the thoracoscopic approach of these diseases is more and more defendable, reason why, more and more surgeons are now considering VATS metastasectomy as a therapeutic procedure especially for isolated lung metastases.
2. Rationale for VATS resection of solitary lung metastasis 2.1. Advantages Despite the initial controversies regarding VATS to treat primary lung malignant diseases, it has become over the past years the method of choice for the management of early NSCLC. By analogy, several surgeons have advocated the use of VATS for the management of isolated pulmonary metastases by highlighting the following advantages: smaller incisions, better visualization of the pleural cavity, less postoperative pain, less surgical morbidity, shorter length of
J.Y. Perentes et al. / Critical Reviews in Oncology/Hematology 95 (2015) 105–113
hospitalization, fewer adhesion in cases of redo metastasectomy, shorter interval between surgery and adjuvant therapy with better treatment compliance [15]. In addition, most pulmonary metastases are generally located in the periphery of the lung, and can be easily resected by VATS. In 1993, Dowling reported the first surgical series of seventy-two patients who underwent VATS resection for metastatic pulmonary lesion [16]. They could report decreased chest tube duration and length of hospital stay. 2.2. Inconvenients However, despite these numerous advantages and this early enthusiasm, VATS metastasectomy has rapidly been included in the area of great controversy. This was mostly related to the fact that bimanual palpation of the lung was not feasible by VATS which could have left behind non visible disease. Another potential concern was whether or not a safe resection margin could be adequately obtained by VATS and the risk of local recurrence at the resection or port sites [17,18]. In 1996, McCormack and colleagues prospectively assessed (CALBG 9336) the efficacy of VATS to detect metastatic lesions following pre-operative CT-Scans [19]. In this study, after resection of all radiologically visible pulmonary nodules by VATS, a thoracotomy was undertaken to perform a bimanual palpation of the lung to identify additional lesions. This study was closed early after 18 of the 50 patients planned due to the high rate (10/18 (56%)) of missed metastatic lesion found during the thoracotomy after VATS exploration. The authors concluded that VATS should be used only for diagnostic procedures due to incomplete excision leading to potentially inferior long term survival. Other later studies have also shown that 16–46% of pulmonary lesions discovered during the bimanual palpation of the lung were not identified on preoperative chest CT-Scans [20–22]. Most of these studies reported patients who were investigated with old generation CT scan studies (5 mm algorithms). Many advances in the field of radiology have since been achieved. For example, spiral CT-scan allows an analysis of the entire lung volume during a single breath-hold thus improving the accuracy of lung nodule detection by eliminating both the respiratory motion artifact and volume averaging. This technique has shown a nodule detection sensitivity of 82% vs. 75% for high-resolution CT-scan [21]. More recent thin slice 1 mm CT-scans were shown to have an even better spatial resolution and are predicted to achieve metastasis detection comparable to a bimanual palpation. In a series of 27 patients, thin sliced (1-mm) chest CT-scan detection of lung metastasis was challenged by bi-manual palpation of the lung by thoracotomy [14]. The sensitivity and the negative predictive value was 97% and 96% respectively in patients with non-sarcomatous tumors. CT-scan is also able to detect small nodules of less than 5 mm, which, in turn increase the rate of false positive intra-pulmonary nodules. Interestingly, Nakajima and al reported that more than 40% of pulmonary
107
nodules smaller than 5 mm in diameter (detected by ChestCTscan) in metastatic patients were not pulmonary metastases [23]. The proper quality of CT-scan imaging is crucial for a successful VATS pulmonary metastasectomy. Based on the previous studies, more than 50% of the additionally resected lung nodules by thoracotomy are benign. This suggests that thoracotomy added morbidity to resect benign nodules in 50% of the cases. Eckardt et al. supported this idea in 2012 in a prospective sequentially controlled study enrolling 37 patient eligible for pulmonary metastasectomy by VATS undergoing first VATS resection by one team, immediately followed by thoracotomy by another team. They found 29 additional nodules during thoracotomy, but 76% of them were benign [24]. Ludwig et al. in 2008 compared the number of pulmonary metastases in 276 patients suspected of pulmonary metastases detected in the pre-operative CT-Scan and during the thoracotomy [25]. The number of lesions found and removed during the operation was higher in 39% than visualized on the preoperative CT scan. For patients with a single nodule on pre-operative CT, only 7% presented more lesions during thoracotomy of which 84% were malignant. Overall, this suggests that 95% of patients with solitary metastasis on chest CT-scan undergo a useless bimanual palpation by thoracotomy according to the current guidelines, Because of this, we believe that in situations of single nodules on pre-operative CT-scans, a VATS approach could be reasonable. 2.3. Controversies VATS is supported by the literature for the management of solitary pulmonary metastases (Table 1). In the past literature, there has been misuse of the terminology “complete resection” [26]. It was well known that incomplete resection of lung metastasis (because of poorly placed or of a bad surgical technique), was a strong predictor of poorer disease free and overall survival. However, the term incomplete resection has been associated to the non resection of a nodule during thoracotomy (non palpated by one surgical team). We prefer to use the term undetectable lesion for these situations. And because of the different biological theories for metastatic spread, it is difficult to predict how a millimetric (
Thoracoscopic resection of pulmonary metastasis: Current practice and results Jean Yannis Perentes a , Thorsten Krueger a , Alban Lovis b , Hans-Beat Ris a , Michel Gonzalez a,∗ a
Division of Thoracic Surgery Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland Division of Pneumonology Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
b
Received 11 August 2014; received in revised form 23 January 2015; accepted 10 February 2015
Contents 1. 2.
3.
4.
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rationale for VATS resection of solitary lung metastasis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1. Advantages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2. Inconvenients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3. Controversies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Long term results of VATS for the management of lung metastasis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1. Studies comparing VATS vs. Open thoracotomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2. Single center studies with VATS metastasectomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3. VATS approach for repeated metastasectomy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4. Hybrid procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conflict of interest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Funding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Biographies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
106 106 106 107 107 108 108 110 111 111 111 112 112 112 113
Abstract Video-assisted thoracoscopic surgery (VATS) is currently a routinely performed procedure for the management of early non small cell lung cancer. The oncological results of VATS in terms of local recurrence and overall survival are equivalent or superior to those of conventional thoracotomy with lower morbidity and hospital stay. In the field of pulmonary metastasectomy, current guidelines support a thoracotomy approach in order to properly palpate the lung and detect nodules too small to be identified on standard radiological examinations (typically less than 5 mm in diameter). However, the oncological and clinical significance of these millimetric nodules is not known. This has led some thoracic surgeons to rethink the approach of solitary pulmonary metastasectomy: because of improvements in thin slice helical CT-scans, some support a VATS approach for solitary pulmonary nodules without formal bimanual palpation and suggest this allows equivalent oncological results and decreased surgical morbidity. © 2015 Elsevier Ireland Ltd. All rights reserved.
Keywords: Video-assisted thoracoscopic surgery; Pulmonary metastasectomy
∗ Correspondence to: Division of Thoracic and Vascular Surgery Centre Hospitalier Universitaire Vaudois Rue du Bugnon 46, 1011 Lausanne/Switzerland Tel.: +41 21 314 24 08; fax: +41 21 314 23 58. E-mail address: [email protected] (M. Gonzalez).
http://dx.doi.org/10.1016/j.critrevonc.2015.02.005 1040-8428/© 2015 Elsevier Ireland Ltd. All rights reserved.
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J.Y. Perentes et al. / Critical Reviews in Oncology/Hematology 95 (2015) 105–113
1. Introduction Approximately 30% of patients suffering from malignant solid tumors will develop pulmonary metastases [1]. Efficient chemotherapy is generally unavailable for most of these tumors. Currently, it is thought that a substantial group of patients with pulmonary metastases may benefit from the resection of lung metastasis. Although there are no prospective randomized studies comparing pulmonary metastasectomy with chemotherapy or observation, surgical resection of pulmonary metastases is nowadays widely performed in selected patients [2]. Several retrospective studies have suggested an increased survival for patients who underwent complete resection of lung metastases in comparison to historical series of patients who did not benefit from lung metastasectomy [3–6]. The largest multicentric study based on the International Registry of Lung Metastases reviewed 5206 patients from 18 centers (USA, Canada and Europe) retrospectively. Complete resection was achieved in 88% of patients and was an important prognostic factor for survival: the 5-year overall survival was of 36% in patients with complete resection compared to 13% in patients with incomplete resection [3]. These results supported that pulmonary metastasectomy offered a survival advantage when complete resection was achievable. Over the past two decades, several studies have supported the role of pulmonary metastasectomy in different tumors types with a 5-year survival rate ranging from 20% to 80% depending on the primary tumor type [7,8]. The improvement of surgical techniques (video assisted thoracoscopic surgery, VATS), radiological imaging (thin slices helical CT-scan), more frequent use of PET-CT and advances with new chemotherapeutic agents have contributed to increase the number of pulmonary metastasectomy procedures and enhance the survival of metastatic patients. The established criteria for lung metastasectomy are [8]: (1) a controlled or controllable primary tumor with no evidence of active disease; (2) the absence of extra-thoracic metastatic disease. However, involvement of other extrathoracic sites may not be a contraindication to the resection of the pulmonary disease if all metastatic sites can be resected completely before the lung resection; (3) complete resection of lung metastasis must be achievable; (4) the patient has sufficient pulmonary and cardiovascular functional reserves to tolerate pulmonary resection; (5) there is no valid alternative therapy. Despite this aggressive strategy, series report up to 50% of patients with local or distant metastatic relapse [3]. The metastasis process is a highly debated and studied topic. Of the multiple theories reported to date, two major metastasis concepts are described and could have an influence in the clinical approach of lung metastasectomy [9]. A first theory suggests a late dissemination of metastasis from the primary tumor after the latter and surrounding environment have acquired sufficient genetic changes for migration and distant implementation function acquisition [10]. A second theory suggests that dissemination occurs very early in the cancer process (sometimes at the pre-malignant stage) and
that single dormant cells can but will not necessarily develop into proper metastasis following genetic and environmental alterations [11]. These theories could occur separately in different tumor types/individuals or may occur together in a same patient. The surgical metastasectomy approach is compatible with a late dissemination process if the five criteria described above are fulfilled. However, in case of an early dissemination process theory, surgical metastasectomy may not be able to achieve complete metastatic resection as premetastatic niches are too small to be palpated. Therefore, a resection approach with surveillance and possibility to redo resection should be favored in this case. Since 1990s, the VATS approach has progressively gained acceptance initially for many basic procedures such as pleural pathologies (pleural biopsy, empyema) and non-anatomical resection for benign diseases (lung biopsies, management of pneumothorax). With growing experience and advances in instrumentation, many surgeons are now routinely performing anatomical lung resections by thoracoscopy with identical standards to those obtained by open thoracotomy. Recently, the American College of Chest Physicians (ACCP) stated in their guidelines that VATS should be preferred over thoracotomy for early lung cancer in experienced centers [12]. However, controversy still exists for the utility of VATS in the resection of isolated pulmonary metastases. While this approach seems to be favored by most thoracic surgeons, there are currently no prospective randomized studies comparing the VATS approach with standard thoracotomy for the resection of lung metastases. VATS is still considered by the European Society of Thoracic Surgery (ESTS) working group for lung metastasectomy as a diagnostic but non therapeutic tool for the management of lung metastases [13]. However, recent thin slice CT scans allow a better spatial resolution and seem to achieve a level of metastasis detection comparable to a bimanual palpation [14]. In addition, several surgical studies have reported solitary pulmonary metastasis in a majority of patients (60–70%). Thus, the thoracoscopic approach of these diseases is more and more defendable, reason why, more and more surgeons are now considering VATS metastasectomy as a therapeutic procedure especially for isolated lung metastases.
2. Rationale for VATS resection of solitary lung metastasis 2.1. Advantages Despite the initial controversies regarding VATS to treat primary lung malignant diseases, it has become over the past years the method of choice for the management of early NSCLC. By analogy, several surgeons have advocated the use of VATS for the management of isolated pulmonary metastases by highlighting the following advantages: smaller incisions, better visualization of the pleural cavity, less postoperative pain, less surgical morbidity, shorter length of
J.Y. Perentes et al. / Critical Reviews in Oncology/Hematology 95 (2015) 105–113
hospitalization, fewer adhesion in cases of redo metastasectomy, shorter interval between surgery and adjuvant therapy with better treatment compliance [15]. In addition, most pulmonary metastases are generally located in the periphery of the lung, and can be easily resected by VATS. In 1993, Dowling reported the first surgical series of seventy-two patients who underwent VATS resection for metastatic pulmonary lesion [16]. They could report decreased chest tube duration and length of hospital stay. 2.2. Inconvenients However, despite these numerous advantages and this early enthusiasm, VATS metastasectomy has rapidly been included in the area of great controversy. This was mostly related to the fact that bimanual palpation of the lung was not feasible by VATS which could have left behind non visible disease. Another potential concern was whether or not a safe resection margin could be adequately obtained by VATS and the risk of local recurrence at the resection or port sites [17,18]. In 1996, McCormack and colleagues prospectively assessed (CALBG 9336) the efficacy of VATS to detect metastatic lesions following pre-operative CT-Scans [19]. In this study, after resection of all radiologically visible pulmonary nodules by VATS, a thoracotomy was undertaken to perform a bimanual palpation of the lung to identify additional lesions. This study was closed early after 18 of the 50 patients planned due to the high rate (10/18 (56%)) of missed metastatic lesion found during the thoracotomy after VATS exploration. The authors concluded that VATS should be used only for diagnostic procedures due to incomplete excision leading to potentially inferior long term survival. Other later studies have also shown that 16–46% of pulmonary lesions discovered during the bimanual palpation of the lung were not identified on preoperative chest CT-Scans [20–22]. Most of these studies reported patients who were investigated with old generation CT scan studies (5 mm algorithms). Many advances in the field of radiology have since been achieved. For example, spiral CT-scan allows an analysis of the entire lung volume during a single breath-hold thus improving the accuracy of lung nodule detection by eliminating both the respiratory motion artifact and volume averaging. This technique has shown a nodule detection sensitivity of 82% vs. 75% for high-resolution CT-scan [21]. More recent thin slice 1 mm CT-scans were shown to have an even better spatial resolution and are predicted to achieve metastasis detection comparable to a bimanual palpation. In a series of 27 patients, thin sliced (1-mm) chest CT-scan detection of lung metastasis was challenged by bi-manual palpation of the lung by thoracotomy [14]. The sensitivity and the negative predictive value was 97% and 96% respectively in patients with non-sarcomatous tumors. CT-scan is also able to detect small nodules of less than 5 mm, which, in turn increase the rate of false positive intra-pulmonary nodules. Interestingly, Nakajima and al reported that more than 40% of pulmonary
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nodules smaller than 5 mm in diameter (detected by ChestCTscan) in metastatic patients were not pulmonary metastases [23]. The proper quality of CT-scan imaging is crucial for a successful VATS pulmonary metastasectomy. Based on the previous studies, more than 50% of the additionally resected lung nodules by thoracotomy are benign. This suggests that thoracotomy added morbidity to resect benign nodules in 50% of the cases. Eckardt et al. supported this idea in 2012 in a prospective sequentially controlled study enrolling 37 patient eligible for pulmonary metastasectomy by VATS undergoing first VATS resection by one team, immediately followed by thoracotomy by another team. They found 29 additional nodules during thoracotomy, but 76% of them were benign [24]. Ludwig et al. in 2008 compared the number of pulmonary metastases in 276 patients suspected of pulmonary metastases detected in the pre-operative CT-Scan and during the thoracotomy [25]. The number of lesions found and removed during the operation was higher in 39% than visualized on the preoperative CT scan. For patients with a single nodule on pre-operative CT, only 7% presented more lesions during thoracotomy of which 84% were malignant. Overall, this suggests that 95% of patients with solitary metastasis on chest CT-scan undergo a useless bimanual palpation by thoracotomy according to the current guidelines, Because of this, we believe that in situations of single nodules on pre-operative CT-scans, a VATS approach could be reasonable. 2.3. Controversies VATS is supported by the literature for the management of solitary pulmonary metastases (Table 1). In the past literature, there has been misuse of the terminology “complete resection” [26]. It was well known that incomplete resection of lung metastasis (because of poorly placed or of a bad surgical technique), was a strong predictor of poorer disease free and overall survival. However, the term incomplete resection has been associated to the non resection of a nodule during thoracotomy (non palpated by one surgical team). We prefer to use the term undetectable lesion for these situations. And because of the different biological theories for metastatic spread, it is difficult to predict how a millimetric (
