Twenty years of video‐assisted thoracoscopic surgery: The past, present, and future

This November, the pioneers of video-assisted thoracoscopic surgery (VATS) gathered in Edinburgh at the 3rd International VATS lobectomy meeting to celebrate the 20th anniversary of VATS pulmonary resection. Experts in the field from the United States, China, and Europe shared their experiences and discussed the innovations and technologies that would see the technique prosper in the 21st century. The first VATS lobectomy was reported in Italy in 1991.1 Several other centers were quick to implement the technique and report successful early operative experience.2, 3 The overall uptake worldwide was modest over the following decade. In 2006, the STS database reported that 32% of lobectomies were performed via VATS,4 whilst here in the UK, acceptance of the technique was slower with only 13% of lobectomies being performed by VATS in 2011.5 Despite obvious potential advantages, adoption of the technique has been slow, which is attributed to several factors. Understandably, there were early concerns from surgeons regarding immediate and long-term outcomes, with oncological efficacy being an initial focus of interest. Furthermore, the technique itself is challenging and is considered to have a demanding learning curve. For others, issues of safety have been paramount and the risks of managing complications, such as massive hemorrhage, have been a source of deterrence. In light of what has now become an overwhelming body of evidence in support of the VATS approach, the above arguments have begun to lose credibility. At the time of writing, VATS has become a well-established technique for the treatment of early stage non-small cell lung cancer (NSCLC).6-9 There are many potential benefits of VATS resection, compared with a traditional muscle-splitting thoracotomy. Established examples include reduced length of hospital stay, decreased blood loss, decreased pain, improved cosmesis, earlier return to normal activities, and improved tolerance of chemotherapy.10-13 Additionally, a reduced level of inflammatory response and preserved immune function has been demonstrated following VATS resections.14, 15 Pulmonary function testing, at one and two weeks post-operatively, has demonstrated accelerated recovery of FEV1 and FVC in VATS lobectomy, compared to the open approach.16 Of even greater significance were the results from a recent systematic review and meta-analysis, of both randomized and non-randomized trials, demonstrating improved outcomes for VATS in relation to systemic recurrence and overall five-year survival when compared with open thoracotomy.17 Despite a multitude of retrospective comparative studies in support of the VATS approach, an ongoing hurdle has been the lack of a large randomized controlled trial (RCT) comparing VATS with open thoracotomy. Critics of the VATS approach have suggested that selection bias in the non-randomized retrospective studies may create a false positive finding of superior outcomes in support of VATS, as a result of patients who are considered more “favorable” being selected in the study group. To date, there exists two small RCT's in which the authors compared patients with NSCLC undergoing VATS lobectomy with resection via open thoracotomy.18, 19 One of the studies demonstrated a significant reduction in overall complications in the VATS group, while the other reported no significant differences in recurrence and survival rates. In addition to small patient numbers, it is noteworthy that rib spreading was performed in the VATS group of both studies, which does not conform to the current “gold standard” definition of VATS as reported in the CALGB study.20 Accordingly, these studies have not satisfied the demand for a large RCT and opinion is currently divided as to whether one is necessary. It also remains uncertain as to whether such a study remains feasible and, indeed, ethical. Recruiting VATS enthusiasts to participate in such a study and subject patients to what they believe to be an inferior operation would no doubt be confounded by personal and ethical dilemmas. Other options might include a preference based study comparing “experts” in both fields or some form of prospective (i.e. prior to surgery) propensity scoring. A large multi-centered RCT has been proposed here in the UK. Whether or not this will prove a feasible project remains to be seen, but, if so, it might offer the opportunity to resolve this debate. At present there are no rigid guidelines regarding patient selection for VATS major pulmonary resection. Most groups currently employ the technique for patients with Stage I NSCLC, who have peripheral tumours, which are less than 6 cm in diameter. Most centers will operate on patients with N1 lymph node involvement with increasing support to operate on individuals with N2 disease. Age is not a contraindication and VATS is often possible in patients who would otherwise not survive an open thoracotomy because of extensive co-morbidities. Moderate (i.e. limited <2 cm diameter) chest wall and pericardial involvement are not necessarily contraindications to VATS resection. Perioperative assessment is patient specific and differs between centers. Most units will assess pulmonary function, via formal spirometry with a predicted FEV1 > 40%, as currently recommended by the British Thoracic Society for open and VATS lung resection,21 which is generally considered as acceptable. There is, in fact, an emerging body of evidence, however, to suggest that VATS resection can safely be performed on individuals with limited pulmonary function and predicted FEV1's of <40% with favourable outcomes in this patient group when compared to the traditional open approach.22-24 Pre-operative staging is achieved via a combination of bronchoscopy and positron emission tomography-computed tomography (PET-CT) scanning. Mediastinal lymph node biopsy is also routinely employed in some centres, because of reported false negative rates of around 5% for the detection of lymph node metastases with PET-CT.25 Endobronchial ultrasound (EBUS) biopsy of mediastinal lymph nodes is utilised as a convenient alternative. A consensus statement regarding patient selection is expected from the 3rd International VATS Lobectomy Conference in Edinburgh, based on the best current evidence and expert opinion. At present there are a number of VATS techniques employed worldwide which differ in both the direction of approach and the number of ports utilized. The approach is typically anterior or posterior (less commonly inferior) and traditionally anywhere between two to four port sites are created.26, 27 More recently, a series of publications have emerged from Spain reporting considerable success performing VATS major lung resections via a single incision.28 To date, there is no convincing evidence to suggest that one approach or technique is superior to the other, and that which is best in the hands of the individual surgeon, remains preferable. The last 10 years have also been witness to the emergence of pulmonary resection being performed by robotic-VATS. Whilst cost effectiveness remains an outstanding issue, early evidence has demonstrated comparable results to traditional VATS and open techniques.29 At present, less than 1% of pulmonary resections are performed by robotic-VATS.30 This is, in part, related to limited availability of the robots, which, even when present in hospitals, are almost exclusively employed in urological and gynaecological procedures. Utilisation of the robot for thoracic procedures is becoming increasingly popular, however. Theoretical advantages over traditional VATS include permission of superior degrees of movement, improved visualization, improved instrumentation and simulated training. In light of these benefits, there are a number of technological innovations specific to robotic-VATS, such as robotic staplers, which will become available in the near future. At present, there is only a single supplier of the robot, and given the cost of the system, it remains to be seen whether the technology adds benefit at a cost that is reasonable. The efficacy of mediastinal lymph node dissection during VATS lobectomy is a further area of controversy. There is limited evidence to suggest that complete dissection of all removable nodes will improve survival and reduce the rates of local recurrence31-33 Current guidelines from the European Society of Thoracic Surgeons have advised the removal of at least three hilar and interlobar nodes, with a further three mediastinal nodes from different stations of which the subcarinal node is always removed.34 Because of a lack of strict regional guidelines, however, this is rarely performed in practice, with selective lymph node sampling being the preference of most thoracic surgeons. Despite concerns that this was related to technical difficulty, there is good evidence to suggest that lymph node dissection with VATS is comparable to open resection35, 36 In light of such findings, it would appear that sub-optimal lymph node sampling/dissection is unrelated to whether the resection has been performed by VATS and is, therefore, a result of non-technical factors. The argument that VATS resections are in some way less effective in terms of oncological efficacy would, therefore, appear invalid and efforts should be made to encourage thorough lymph node dissection until more conclusive evidence becomes available. Looking to the future, it is encouraging to see that the individuals, whose dedication and perseverance ensured that VATS became an established technique for major lung resections, continue to push the boundaries of achievement two decades later. As interest grows, the technologies inevitably continue to advance. High definition camera systems are now commonplace and provide a remarkable improvement in exposure, when compared with the imaging systems employed in the early days of VATS. The instruments themselves have become better refined and the development of endoscopic staplers specific for VATS has been one of the greatest innovations to date. These technological advances have led to safer surgery and expanded the potential for curative surgery in patients who previously may have been declared inoperable. Perhaps the greatest advances, however, will arise as a product of education and training. The limited dissemination of VATS in many countries has been, in part, because of a lack of individuals with sufficient experience to teach the technique. In general surgery, junior trainees are now as familiar with routine laparoscopic operations as with the traditional open techniques. This has yet to become the case with thoracic surgery, where trainees often have limited, if any, exposure to VATS major lung resections. We are, however, part of an era where emphasis is given to minimally invasive techniques, cost effectiveness, and rapid recovery from surgery. In light of this drive, it is hoped that training in VATS lobectomy will become a compulsory component of thoracic surgical training worldwide. Initial fears regarding the oncological efficacy of VATS resections have not been realized. The technique is now well established as a safe and cost effective alternative to open surgery in patients with early stage NSCLC. The technique has also expanded the potential for curative disease in elderly, frail, co-morbid patients who would otherwise not have tolerated an open resection. In a climate where practice is based on the best available evidence it would seem inevitable that VATS major lung resection will soon be universally accepted as the gold-standard. No authors disclose any conflict of interest.