Do we need any further evidence about minimally invasive thoracic surgery?

In the last decade the development of thoracoscopic approach for early stage lung cancer resections has seen a significant increase, mostly because of the improvement in technology. Some organizations (1) even recommend it in their guidelines. Yet in striking contrast with modern evidence-based practice, such enthusiasm is only underpinned by mostly small, retrospective trials comparing video-assisted thoracoscopic surgery (VATS) to open thoracotomy. By contrast, Bendixen (2) and colleagues’ randomised controlled trial offers an objective assessment in terms of postoperative pain and quality of life (QoL), further consolidating previous evidence. Previous papers compared different type of VATS with different open approaches, thus affecting the quality of the results. Interestingly Bendixen and colleagues compare VATS with anterior thoracotomy, which is considered to be the least invasive open approach. Whilst, intuitively, sparing the latissimus dorsi is likely to be better than posterolateral thoracotomy, demonstrating the advantage of VATS over anterior thoracotomy is a further positive point in this study.

Most techniques in surgery follow a typical distribution curve: there is resistance at first, then it reaches a tipping point after which adoption grows exponentially. Doing a trial after the tipping point might seem unethical and unfeasible. That is why we read with interest the paper of Bendixen and colleagues as the first randomized control trial comparing the outcomes of VATS vs. open surgery. From the growing body of non-randomised studies, VATS is generally assumed to be less traumatic than thoracotomy, with reduced postoperative pain, perioperative bleeding, length of hospital stay, and faster return to normal activities. Bendixen and colleagues results support this assumption in terms of postoperative pain and QoL.

There are few issues, though, with this trial that we would like to be addressed in any future trial such as the VIOLET by Eric Lim. The first thing to note in this well-executed study is the choice of endpoints: postoperative pain and overall QoL. Although these are important things to consider after surgery we have some reservation about the choice. Pain has two components: inflammatory, related to the actual incision and neuropathic related to the compression of the intercostal nerve by the spreader, in open surgery, or the trocar in VATS surgery. The authors prefer to use the four ports approach. One might wonder whether the pain would be even less with the uniportal approach (3) which avoids the use of trocars altogether and limits the incision to one intercostal space rather than several. Somehow it is disappointing to have chosen a four ports approach as this one is slowly disappearing in favor of a one to three approach. It would be interesting to know whether the number of ports affect the outcome.

Pain is also a notoriously difficult endpoint to measure due to the interpatient variability and the different analgesic regime. Furthermore, in the trial the test for the QoL is a global measure, we wonder whether a more specific lung cancer focused QoL score would be more discriminatory and allow clearer results. Concept like lung cancer expected survival and postoperative dyspnea are important for this group of patients.

The further point we would like to make is that VATS is an approach not a new operation. As such we should be evaluating the oncological results and the overall survival, at least in terms of non-inferiority. Unfortunately, though such outcomes were not primary endpoints in the Bendixen trial and it was not adequately powered for such investigations.

However, the real question remaining is can a minimally invasive approach be at least as effective as standard thoracotomy in terms of oncological results, safety and long-term outcomes? So far, no clear evidence on this point has been provided. Hopefully the VIOLET trial (4) will shed some light on this important question and we look forward to reading the conclusions.

Acknowledgements

Funding: None.

Footnote

Provenance and Peer Review: This article was commissioned and reviewed by the Section Editor Qing-Yuan Huang (Department of Thoracic Surgery, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China).

Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/amj.2017.04.06). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

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4. Video-assisted thoracoscopic lobectomy (VATS) versus conventional Open Lobectomy for lung cancer. Available online: http://www.isrctn.com/ISRCTN13472721