Lung cancer is still the most common malignancy worldwide (1, 2), and the main effective treatment is surgery for early-stage non-small-cell lung cancer (NSCLC) (3, 4). Emerging evidence has revealed that video-assisted thoracic surgery (VATS) is also a safe and effective treatment method for NSCLC compared with conventional thoracotomy (5–7). Additionally, it has been reported that VATS patients have less postoperative pain, shorter hospital length of stay, fewer complications, faster physical recovery, and better postoperative lung function outcomes than thoracotomy patients (5, 6, 8). Based on these advantages, VATS (including uniportal, two-port, three-port, or four-port) has been widely used to treat lung cancer. Although VATS is widely used in thoracic surgery based on its advantages, it also suffers from shortcomings, such as two-dimensional vision, difficult hand–eye coordination, amplification of hand tremor, steep learning curve, lack of flexibility, and limited ranges of instrument movement (8). Based on new emerging technologies and advances in medical knowledge, robot-assisted thoracic surgery (RATS) may be an alternative to VATS, as RATS can provide 3D high-definition visualization over the operative field, increase comfort for the surgeon, and improve the precision of manipulations with tremor filtration and instrument dexterity (9). Some studies have confirmed the safety and feasibility of RATS (7, 9) and emphasized its advantages in less bleeding, lower conversion rate, shorter hospital stay, more harvested lymph nodes and stations, lower overall complication rate, and lower recurrence rate (8) due to 3D high-definition visualization, tremor filtration, and instrument dexterity of robotic surgery systems. With several new studies about RATS and VATS for NSCLC published recently, a new updated meta-analysis is urgently needed to compare the perioperative and oncologic outcomes of RATS and VATS for NSCLC.

Lobectomy with lymphadenectomy is regarded as the standard surgical treatment for patients with early-stage NSCLC. Due to the popularity of high-resolution CT for screening NSCLC, numerous small early-stage NSCLC (tumor diameter ≤2 cm) are captured (39). Recent reports have shown that sublobar resection or segmentectomy with lymph node sampling has similar outcomes compared with lobectomy for small early-stage NSCLC patients (39, 40). During the past decade, there is sufficient evidence that minimally invasive surgery (MIS) can be used as an alternative standard for NSCLC (5). MIS, including VATS and RATS, could strongly improve short-term outcomes and maintain equivalent long-term outcomes compared with traditional thoracotomy (7, 41). Currently, RATS has been increasingly used worldwide as a new surgical approach for NSCLC.

Although some meta-analyses have demonstrated that RATS is a feasible and safe alternative compared with VATS (7, 8, 42), the debate about the type of operation chosen for NSCLC continues to maintain people’s attention. We read two meta-analyses with great interest published recently by Wu et al. and Ma et al., who aimed to compare the short-term and long-term efficacy between RATS and VATS for NSCLC. Although the research by them was well conducted, unfortunately, we found some flaws in their studies. In the study by Ma et al. (8), we found that the included original articles contained benign lung diseases and metastatic lung cancer, and not all pathologies were NSCLC, which could lead to potential bias in the results. In another study by Wu et al. (7), one study was retracted because this research was fabricated and was included in the analysis of postoperative complications, which could lead to potential flaws in the research. Meanwhile, several new studies were published recently; 26 studies, including 2 randomized controlled trials, 8 propensity score matching studies, and other retrospective studies, were included based on strict inclusion criteria, and an updated meta-analysis was conducted to explore and compare the clinical efficacy of RATS and VATS for patients with NSCLC from 2011 to 2021. Our study included a total of 45,733 patients from 26 studies comparing RATS and VATS, and we focused on both the short-term and long-term oncological outcomes of RATS and VATS for NSCLC.

In short, this meta-analysis did not detect any statistically significant differences in operative time, any complications, tumor size, chest drain duration, R0 resection rate, lymph station, 5-year overall survival, or recurrence rate. However, less blood loss (p value = 0.003; 95% CI -65.99 to -14.08), a lower conversion rate to open (p value = 0.004; 95% CI 0.45 to 0.85), a shorter length of hospital stay (p value = 0.02; 95% CI -0.60 to -0.04; I² = 99%), more lymph node dissection, and a better 5-year disease-free survival (p value = 0.01; 95% CI 1.11 to 2.57; I² = 23%) were captured in RATS than VATS. The results of the meta-analysis revealed that the operative time, any complications, chest drain duration, and number of lymph stations were similar between the two groups, which was consistent with the results reported by Liang et al. (42). Regarding less blood loss and a lower conversion rate to open, the possible reason is that RATS has better visualization and reduces natural tremors. Thorough oncological surgical margins and lymph node dissections are two important malignancy prognosis factors in the surgical approach for NSCLC. There was no significant difference in terms of the R0 resection rate or recurrence rate between RATS and VATS, which showed that both RATS and VATS are feasible surgical techniques for NSCLC. However, more lymph node dissection and a better 5-year disease-free survival were captured in RATS compared with VATS, which might be related to the robot system being flexible operating instruments and having a greater advantage in obtaining lymph nodes, and more lymph node dissection could lead to a better 5-year DFS for patients with NSCLC. Moreover, the 5-year overall survival was similar in the two groups, while a better 5-year disease-free survival was found in RATS, which was similar to the results of a previous study (7).

To evaluate the safety and efficiency of RATS for NSCLC, this meta-analysis included 26 studies and showed that RATS was comparable to VATS. However, this review has some limitations that should be considered. First, there were only two RCTs out of all 26 included studies, which may have contributed to selection bias. Furthermore, of the 26 included studies, the long-term oncological outcomes with NSCLC have not been reported in most of the studies (including the two RCTs that did not report the long-term survival outcomes of NSCLC). Moreover, there was obvious publication bias with the included studies. Therefore, further studies, particularly large-scale prospective studies and RCTs, are expected to assess the effectiveness and safety of RATS for patients with NSCLC.

In conclusion, this systematic review and meta-analysis suggests that RATS is a technically and oncologically safe and feasible approach for NSCLC patients. Large randomized and controlled prospective studies are needed to confirm the superiority of RATS.

JZ, QF, YH, and FL designed the project. JZ, QF, and YH extracted the data, made the figures and tables, and wrote the manuscript. LO and FL revised the manuscript. All authors reviewed manuscript. All authors contributed to the article and approved the submitted version.

This work was supported by grants from the National Natural Science Foundation of China (No. 82060390).

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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