Robot-assisted thoracic surgery in the era of pulmonary segmentectomy for non-small cell lung cancer

Since the Lung Cancer Study Group published a study comparing lobectomy and sublobar resection for small-sized non-small cell lung cancer (NSCLC) and reporting a higher locoregional recurrence rate and poorer postoperative survival with sublobar resection (1), lobectomy has been the standard surgical treatment for NSCLC, regardless of tumor size. However, recent large-scale, multi-institutional, randomized studies of lobectomy versus sublobar resection for peripheral NSCLC ≤2 cm suggest non-inferior postoperative survival after sublobar resection compared to lobectomy (2,3). Thus, segmentectomy appears to be a more common choice for the surgical treatment of small-sized NSCLC, and the number of segmentectomies performed worldwide is increasing (4,5). Robotic-assisted thoracic surgery (RATS) enables precise manipulation of the surgical field with highly flexible instruments that feature wristed joints and a high-definition, three-dimensional camera. Due to these characteristics, the RATS approach is better suited for complex procedures, such as pulmonary segmentectomy, than lobectomy. Therefore, general thoracic surgeons should be interested in using RATS for segmentectomy.

Many studies reporting the initial results of RATS segmentectomy concluded that the procedure is safe and feasible, given the short operation time and low rates of postoperative complications and conversion to conventional thoracotomy (6-11). Anatomic segmentectomy requires more precise dissection than lobectomy, so the RATS approach may be well suited for it (6). The RATS approach allows for precise dissection of the segmental bronchopulmonary structures while reducing the risk of trauma to the surrounding tissue (8). The fourth arm provides greater exposure for hilar vascular dissection (7). The RATS approach has the limitation of resection without palpation of the tumor. However, preoperative three-dimensional images can help identify lesions and anatomical structures, such as vessels and the bronchus. A three-dimensional view is useful for creating intersegmental planes (9). Preoperative planning with a deep understanding of the target segment and bronchovascular anatomy using three-dimensional lung reconstruction software may reduce the need for converting to lobectomy (12). In addition, during RATS, using an intravenous indocyanine green dye with a robotic camera can illuminate non-target segments, making it easier and more precise to identify intersegmental planes (10,13). Precise dissection by RATS is also useful for complete dissection of the mediastinal and hilum nodes (8). The RATS technique is considered to have the potential to expand the use of segmentectomy. In fact, the use of robots contributed to an increase in the number of segmentectomies performed on patients undergoing anatomic pulmonary resection (11).

Video-assisted thoracoscopic surgery (VATS) has replaced conventional open thoracotomy and has become established as a minimally invasive technique involving small incisions, less postoperative pain, and a low rate of complications after surgery (14). Therefore, comparing the VATS and RATS approaches in pulmonary segmentectomy is of interest to general thoracic surgeons. Characteristics of RATS are expected to overcome some of the limitations of the VATS approach. In previous retrospective studies comparing RATS and VATS or VATS/open approaches in pulmonary segmentectomy (15-21), the authors firstly addressed operative time. The median operative time for RATS segmentectomy was reported as 59–205 minutes. This time is shorter than that for VATS or VATS/open approaches and is non-inferior (16-21), while one study suggested that the operative time of RATS segmentectomy is relatively longer than that for conventional open thoracotomy (15). Although previous studies suggested similar operative times for RATS and VATS or VATS/open approaches in pulmonary segmentectomy, some advantages in the RATS segmentectomy learning curve were reported (22,23). Many studies have indicated that RATS segmentectomy results in a significantly smaller amount of intraoperative bleeding (median: 10–99 mL) than VATS or VATS/open approaches (15,17-20). The RATS segmentectomy may also have advantages for converting to a conventional open thoracotomy during the operation (24). The postoperative total drainage volume was smaller with RATS segmentectomy (median: 185–475 mL) than with VATS segmentectomy (19-21), and the duration of chest drainage was similar between the two procedures (median: 2–3 days) (15,17,19-21). In terms of postoperative complications, most studies indicated favorable results for RATS segmentectomy compared to VATS or VATS/open approaches (15-20,24). Gómez-Hernández et al. reported no significant differences in total postoperative complications, cardiopulmonary complications, major complications, prolonged air leak, arrhythmia, or reoperation between RATS and VATS segmentectomies (16). Because segmentectomy requires sparing lung parenchyma, controlling postoperative air leakage is an important issue for pulmonary segmentectomy compared to lobectomy. However, some studies have suggested that the RATS approach results in an even lower incidence rate of postoperative air leakage than the VATS or open approaches (16,20). One possible explanation is the delicate manipulation of the lung without injury by highly flexible instruments that feature wristed joints and a high-definition, three-dimensional camera (25). The median length of stay for RATS segmentectomy is reported to be 3–4 days, which is shorter than for VATS or open segmentectomies. (15,16,19-21).

It is important to mention the possible disadvantages of RATS segmentectomy. Needless to say, one of the biggest issues with the RATS procedure is the high cost of hospitals, primarily due to the expensive robotic system (26). Even in RATS segmentectomy, the RATS approach was reported to be more costly than the VATS approach (20). Okazaki et al. also found that RATS required a significantly higher number of staplers than VATS, which is another reason for the higher cost of RATS segmentectomy (18). Robotic surgery programs still have specific economic issues regarding adoption, integration, and scaling up due to their high capital and consumable costs, especially in low- and middle-income countries. However, if the RATS approach can provide a lower rate of postoperative complications and a shorter hospital stay than the VATS approach, it may offset the higher cost of RATS segmentectomy. Further considerations regarding the costs of RATS are required, including ICU and total hospital stay costs, as well as differences in the medical insurance systems of each country. One study indicated that patients who underwent RATS segmentectomy experienced more pain during the first week after discharge than those who underwent uniportal VATS segmentectomy (21). This is due to the multiportal nature of the RATS procedure.

In terms of oncological treatment, previous studies have suggested harvesting a similar number of lymph nodes for RATS and VATS procedures during segmentectomy for NSCLC (21,24,26-28). In theory, the high-definition, three-dimensional view and precise dissection of the RATS procedure are suitable for lymphadenectomy in NSCLC. Some of the aforementioned studies have indicated a superior effect of RATS in harvested lymph nodes and nodal upstaging compared to VATS (26-28). Some previous meta-analyses suggested that more lymph nodes were harvested in RATS than in VATS for lobectomy/segmentectomy (26,27). A recent study suggested a similar R0 resection rate for RATS and VATS segmentectomies (29). RATS showed a greater negative tumor margin distance compared with VATS. Many previous studies have reported comparable postoperative survival rates between RATS and VATS segmentectomies for NSCLC (19,26,28,30). Some of these studies have suggested that the RATS procedure is associated with improved survival and a lower recurrence rate (26,30). However, the non-inferiority of RATS segmentectomy compared with VATS is not clearly established in terms of long-term survival.

One of the major limitations of this study is that, since there are no randomized prospective studies comparing RATS and other minimally invasive approaches in pulmonary segmentectomy, data were obtained from retrospective studies. Thus, the results of this study may be biased toward RATS. Prospective randomized trials are necessary for definitive conclusions. Another limitation of the study is the heterogeneity of the VATS approach, including multiportal, uniportal, and hybrid approaches.

In conclusion, previous studies that have compared RATS and VATS/open segmentectomies have reported similar perioperative outcomes for both procedures. In some areas, such as intraoperative bleeding, lymphadenectomy, and air leakage control, the RATS procedure appears to be superior to the conventional VATS and open approaches. From an oncological perspective, RATS showed non-inferior short-term outcomes, such as resectability and postoperative disease control, and may have some advantages regarding the quality of lymphadenectomy. Therefore, for patients with small-sized NSCLC who would undergo pulmonary segmentectomy with a minimally invasive approach, RATS segmentectomy could be a viable option. In the future, it is expected that the indications for RATS segmentectomy for NSCLC will expand further due to the accumulation of experience and the evolution of robotic mechanisms. Moreover, prospective randomized studies comparing RATS and VATS segmentectomies are required for definitive conclusions regarding postoperative complications, quality of life, certainty and quality of complex segmentectomies, oncologic outcomes (including resectability, lymphadenectomy, and long-term survival), and total cost-effectiveness when considering total hospital stays and patients’ quality of life.

Acknowledgments

None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Video-Assisted Thoracic Surgery. The article has undergone external peer review.

Peer Review File: Available at https://tcr.amegroups.com/article/view/10.21037/vats-2025-1-51/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tcr.amegroups.com/article/view/10.21037/vats-2025-1-51/coif). T.K. receives honoraria for presentations from Intuitive Surgical G.K. The other authors have no conflicts of interest to declare.

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