Comparison of Short-Term Outcomes Between Robot-Assisted and Video-Assisted Segmentectomy for Small Pulmonary Nodules: A Propensity Score-Matching Study.

BACKGROUND: Our study aimed to compare the short-term outcomes between robot-assisted segmentectomy (RAS) and video-assisted segmentectomy (VAS) for small pulmonary nodules. METHODS: The study included of 299 segmentectomies (132 RAS and 167 VAS procedures) for small pulmonary nodules between June 2018 and November 2021. The patients were divided into two groups: the RAS group and the VAS group. Propensity score-matching (PSM) analysis was performed to minimize bias. A logistic regression model was performed to identify the independent risk factors associated with complications. RESULTS: Before PSM, the following clinical variables were not balanced: age (P = 0.004), tumor size (P < 0.001), forced expiratory volume for 1 s (FEV1), and FEV1 percentage (P < 0.001). The patients with RAS had a shorter operative time (P = 0.014), less blood loss, a shorter postoperative hospital stay, less use of strong opioids, less drainage on postoperative day 1, and less postoperative total drainage, but more cost (all P < 0.001). Conversion to open surgery was performed for two patients in the VAS group but none in the RAS group. After PSM, 53 pairs were successfully matched. The data again suggested that the patients with RAS had less blood loss, a shorter postoperative hospital stay, and less use of strong opioids, but more cost (all P < 0.001). The operation time also was shorter in the RAS group, with a borderline statistically significant P value (0.053). CONCLUSIONS: In our study, RAS had better short-term outcomes than VAS, indicating a safer and more efficient technique than VAS.

Resectable lung lesions malignancy assessment and cancer detection by ultra-deep sequencing of targeted gene mutations in plasma cell-free DNA.

BACKGROUND: Early detection of lung cancer to allow curative treatment remains challenging. Cell-free circulating tumour (ct) DNA (ctDNA) analysis may aid in malignancy assessment and early cancer diagnosis of lung nodules found in screening imagery. METHODS: The multicentre clinical study enrolled 192 patients with operable occupying lung diseases. Plasma ctDNA, white cell count genomic DNA (gDNA) and tumour tissue gDNA of each patient were analysed by ultra-deep sequencing to an average of 35 000× of the coding regions of 65 lung cancer-related genes. RESULTS: The cohort consists of a quarter of benign lung diseases and three quarters of cancer patients with all histopathology subtypes. 64% of the cancer patients are at stage I. Gene mutations detection in tissue gDNA and plasma ctDNA results in a sensitivity of 91% and specificity of 88%. When ctDNA assay was used as the test, the sensitivity was 69% and specificity 96%. As for the lung cancer patients, the assay detected 63%, 83%, 94% and 100%, for stages I, II, III and IV, respectively. In a linear discriminant analysis, combination of ctDNA, patient age and a panel of serum biomarkers boosted the overall sensitivity to 80% at a specificity of 99%. 29 out of the 65 genes harboured mutations in the patients with lung cancer with the largest number found in TP53 (30% plasma and 62% tumour tissue samples) and EGFR (20% and 40%, respectively). CONCLUSION: Plasma ctDNA was analysed in lung nodule assessment and early cancer detection, while an algorithm combining clinical information enhanced the test performance. TRIAL REGISTRATION NUMBER: NCT03081741.

Intratumor heterogeneity comparison among different subtypes of non-small-cell lung cancer through multi-region tissue and matched ctDNA sequencing.

Understanding of intratumor heterogeneity (ITH) among different non-small cell lung cancer (NSCLC) subtypes is necessary. Whether circulating tumor DNA (ctDNA) profile could represent these ITH is still an open question. We performed 181 multi-region tumor tissues sequencing and matched ctDNA sequencing from 32 operative NSCLC to compare ITH among different NSCLC subtypes, including EGFR-mutant lung adenocarcinoma (LUAD), KRAS-mutant LUAD, EGFR&KRAS-wild-type LUAD, and lung squamous cell carcinoma (LUSC), and examine potential value of ctDNA for ITH analysis. ITH is evaluated by ITH index (ITHi). If the somatic genetic alteration is shared by all the tissue regions, it is defined as trunk mutation. Otherwise, it is called branch mutation. The ITHi will be higher, if the tumor has less trunk mutations. We found EGFR-mutant LUAD showed significantly higher ITHi than KRAS-mutant LUAD/wild-type LUAD (P = 0.03) and numerically higher ITH than LUSC. For trunk mutations, driver mutations were identified at a higher proportion than passenger mutations (60% vs. 40%, P = 0.0023) in overall, especially in EGFR-mutant LUAD (86% vs. 14%, P = 0.0004), while it was opposite in KRAS-mutant LUAD (40% vs. 60%, P = 0.18). For branch mutations, the proportions of driver mutations and passenger mutations were similar for each NSCLC subtype. ctDNA analysis showed unsatisfactory detections of tumor-derived trunk and branch mutations (43% vs. 23%, P = 4.53e-6) among all NSCLC subtypes. In summary, EGFR-mutant LUAD has the highest ITH than other NSCLC subtypes, offering further understanding of tumorigenesis mechanisms among different NSCLC subtypes. Besides, ctDNA maybe not an appropriate method to reflect ITH.

Incidence and Distribution of Lobe-Specific Mediastinal Lymph Node Metastasis in Non-small Cell Lung Cancer: Data from 4511 Resected Cases.

OBJECTIVE: We aimed to investigate the incidence and distribution of mediastinal lymph node metastases (MLNM) in operable non-small cell lung cancer (NSCLC) with the purpose of guiding mediastinal lymph node dissection (MLND). METHODS: A total of 4511 NSCLC patients who underwent resection between January 2001 and December 2014 were included. These patients were preoperatively untreated and grouped according to the primary tumor lobes. The incidence and distribution of pathologic MLNM were compared among groups, and multivariate analysis was conducted to find the independent factors impacting MLNM. RESULTS: Lymph node involvement was observed in 1784 patients (39.5%). A total of 628 cases (13.9%) were N1-positive only, 752 cases (16.7%) were both N1- and N2-positive, and 404 cases (9.0%) were N2-positive only. The most common sites of mediastinal metastasis for different primary tumor lobes were the right upper lobe, station 4R (21.5%, 192/893); right middle lobe, station 7 (21.1%, 69/327); right lower lobe, station 7 (24.1%, 212/878); left upper lobe, station 5 (22.2%, 224/1008); and left lower lobe, station 7 (21.7%, 136/628). However, when only N2 cases were considered, each mediastinal lymph node zone can be involved with metastasis to a high proportion (> 5%). Multivariable analyses showed that poor cell differentiation, adenocarcinoma, larger tumor size, central type, and younger age were independent factors favoring MLNM. CONCLUSIONS: Different primary tumor locations have a different propensity to be sites of MLNM; however, once MLNM occurs, each zone can be involved and should not be neglected. Systematic MLND is the preferred procedure for operable NSCLC.

Efficacy of Endoscopic Ultrasonography for Determining Clinical T Category for Esophageal Squamous Cell Carcinoma: Data From 1434 Surgical Cases.

BACKGROUND: The efficacy of endoscopic ultrasonography (EUS) for determining T category is variable for esophageal squamous cell carcinoma (ESCC). We aimed to assess the efficacy of EUS in accurately identifying T category for ESCC based on the 8th AJCC Cancer Staging Manual. METHODS: A retrospective analysis was conducted using a prospectively collected ESCC database from January 2003 to December 2015, in which all patients underwent EUS examination followed by esophagectomy. The efficacy of EUS was evaluated by sensitivity, specificity, and accuracy compared with pathological T category as gold standard. Overall survival of different EUS-T (uT) categories was assessed. RESULTS: In total, 1434 patients were included, of whom 58.2% were correctly classified by EUS, with 17.9% being overstaged and 23.9% being understaged. The sensitivity and accuracy of EUS for Tis, T1a, T1b, T2, T3, and T4a categories were 15.8 and 98.8%, 16.3 and 95.7%, 33.1 and 89.3%, 56.8 and 65.0%, 65.8 and 70.0%, and 27.3 and 97.5%, respectively. The survival difference between uT1a and uT1b was not statistically significant (p = 0.90), nor was that between uT4a and uT4b (p = 0.34). However, when uT category was integrated as uTis, uT1, uT2, uT3, and uT4, overall survival was clearly distinguished between the categories (p < 0.01). CONCLUSIONS: EUS is in general feasible for classifying clinical T category for ESCC. However, EUS should be used with caution for discriminating between Tis, T1a, and T1b disease, as well as T4 disease.

p300 promotes proliferation, migration, and invasion via inducing epithelial-mesenchymal transition in non-small cell lung cancer cells.

BACKGROUND: Histone acetyltransferase p300 is a crucial transcriptional coactivator and has been implicated as a poor prognostic factor in human cancers. However, little is known about the substantial functions and mechanisms of p300 in NSCLC proliferation and distant metastasis. METHODS: We constructed p300 down-regulated and up-regulated cell lines through RNAi and recombinant plasmid transfection. Cell Counting Kit-8 assays were used to test the cell proliferation and confirmed by colony formation assays. Wound healing assays and transwell chamber assays were used to test the migration and invasion ability. Based upon these results, we measured the epithelial markers and mesenchymal markers after regulating p300 expression to explore epithelial-mesenchymal transition as a potential mechanism of p300 promoting NSCLC metastasis. RESULTS: In NSCLC cells NCI-H1975 and NCI-H1993, down-regulation of p300 leads to inhibition of cell proliferation and colony formation. Cells with reduced p300 expression also demonstrate inhibited migration and invasion ability. Contrarily, up-regulation of p300 significantly enhanced the proliferation, colony formation, migration and invasion ability of NCI-H460. Importantly, further investigation shows that decreased p300 expression is associated with reduced expression of mesenchymal markers and increased expression of epithelial markers, while up-regulated p300 expression correlated with decreased expression of epithelial markers and increased expression of mesenchymal markers. CONCLUSIONS: As a crucial tumor promoter, p300 promotes cell proliferation, migration, and invasion in NSCLC cells. Epithelial-mesenchymal transition is a potential mechanism of p300 promoting NSCLC metastasis.

Long-term Survival Based on the Surgical Approach to Lobectomy For Clinical Stage I Nonsmall Cell Lung Cancer: Comparison of Robotic, Video-assisted Thoracic Surgery, and Thoracotomy Lobectomy.

OBJECTIVE: To compare the long-term outcomes among robotic, video-assisted thoracic surgery (VATS), and open lobectomy in stage I nonsmall cell lung cancer (NSCLC). BACKGROUND: Survival comparisons between robotic, VATS, and open lobectomy in NSCLC have not yet been reported. Some studies have suggested that survival after VATS is superior, for unclear reasons. METHODS: Three cohorts (robotic, VATS, and open) of clinical stage I NSCLC patients were matched by propensity score and compared to assess overall survival (OS) and disease-free survival (DFS). Univariate and multivariate analyses were performed to identify factors associated with the outcomes. RESULTS: From January 2002 to December 2012, 470 unique patients (172 robotic, 141 VATS, and 157 open) were included in the analysis. The robotic approach harvested a higher number of median stations of lymph nodes (5 for robotic vs 3 for VATS vs 4 for open; P < 0.001). Patients undergoing minimally invasive approaches had shorter median length of hospital stay (4 d for robotic vs 4 d for VATS vs 5 d for open; P < 0.001). The 5-year OS for the robotic, VATS, and open matched groups were 77.6%, 73.5%, and 77.9%, respectively, without a statistically significant difference; corresponding 5-year DFS were 72.7%, 65.5%, and 69.0%, respectively, with a statistically significant difference between the robotic and VATS groups (P = 0.047). However, multivariate analysis found that surgical approach was not independently associated with shorter OS and DFS. CONCLUSIONS: Minimally invasive approaches to lobectomy for clinical stage I NSCLC result in similar long-term survival as thoracotomy. Use of VATS and robotics is associated with shorter length of stay, and the robotic approach resulted in greater lymph node assessment.

The impact of tumor cell differentiation on survival of patients with resectable esophageal squamous cell carcinomas.

BACKGROUND: The current American Joint Committee on Cancer staging system considers tumor cell differentiation grade to be a factor in the staging of esophageal squamous cell carcinoma (ESCC) in pathologic T0-3N0M0 cases. However, more data are essential to test its efficacy. We sought to investigate the tumor-node-metastasis categories for which tumor cell grade might affect overall survival in Chinese patients. METHODS: We conducted a retrospective review of 1,220 patients with ESCC who underwent complete resection between December 1996 and December 2008. Survival was calculated by the Kaplan-Meier method, and the log-rank test was used to assess differences in survival between groups. Subgroup analyses and the Cox proportional hazards model were used to further determine the effect of tumor cell grade on overall survival. RESULTS: The 5-year survival rates for the G1, G2, and G3 groups of pathologic T2N0M0 ESCC cases were 80.1, 61.9, and 47.4%, respectively (p = 0.015), and these rates in the pathologic T3N0M0 ESCC cases were 66.7, 61.7, and 41.2%, respectively (p = 0.020). However, the differences in the survival of the different tumor cell grade groups of the pathologic T1N0M0 (p = 0.198) and the node positive categories (p = 0.063) were not statistically significant. Multivariate Cox regression analysis confirmed that tumor cell grade independently affected the overall survival of patients with pathologic T2-3N0M0 ESCC. CONCLUSIONS: The staging of ESCC in the Chinese population should be simplified by omitting tumor cell grade as a variable in patients with pathologic T1N0M0 disease. More data are needed to verify our results.

Vascular Endothelial Growth Factor is a Useful Predictor of Postoperative Distant Metastasis and Survival Prognosis in Esophageal Squamous Cell Carcinoma.

BACKGROUND: The correlation between vascular endothelial growth factor (VEGF) and prognosis for patients with esophageal squamous cell carcinoma (ESCC) is controversial. This study investigated the correlation of VEGF expression with distant metastases and prognosis in resectable ESCC to improve the identification of patients with increased risk of postoperative metastases. METHODS: Data from two centers were used to establish a training cohort (n = 319) and a validation cohort (n = 164). Tissue microarrays were generated for immunohistochemical evaluation. The correlations among VEGF expression, clinicopathologic variables, and prognosis were analyzed. The outcomes generated from the training cohort then were tested using the validation cohort. Multivariate analyses were used to test the independent factors that had an impact on postoperative distant metastases, overall survival (OS), and distant metastasis-free survival (DMFS). RESULTS: Tumor stages, tumor cell grade, and VEGF expression were prognostic factors independent of ESCC outcome. The data indicated that high levels of VEGF expression were correlated with a high risk of postoperative distant metastases (p = 0.013) in the training cohort. This result was confirmed by the validation cohort (p < 0.01) and logistic regression analyses. A high level of VEGF expression also was correlated with poor DMFS (p = 0.011) and OS (p = 0.033) in the training cohort, which also was confirmed by the validation cohort and Cox regression analyses. CONCLUSIONS: Expression of VEGF is a predictor of distant metastasis, OS, and DMFS in resectable ESCC patients. Using a combination of VEGF expression, tumor stages, and tumor cell grade, identification of patients with increased risk of postoperative metastases may become possible.

Proposed modification of the seventh American Joint Committee on Cancer staging system for esophageal squamous cell carcinoma in Chinese patients.

BACKGROUND: More data are essential to test the efficacy of the American Joint Committee on Cancer (AJCC) system for staging esophageal squamous cell carcinoma (ESCC). On the basis of previous studies, we propose a modification to this system to better represent the survival characteristics of ESCC in the Chinese population. METHODS: We used data from two centers to establish the generating (n = 1006) and validation (n = 783) cohorts. All of the patients underwent curative surgical treatment. On the basis of previous studies, we excluded tumor location as a variable in the modified pathological staging system and defined the modified nodal categories as follows: N0, node negative; N1, 1 positive node; N2, 2 to 3 positive nodes; and N3, >3 positive nodes. The pathological T categories, pathological M categories, and cell differentiation in the seventh AJCC staging system for adenocarcinoma were used in the modified pathological staging system for ESCC. RESULTS: The median survival times for ESCC patients with stage 0 and Ia, stage Ib, stage IIa, stage IIb, stage IIIa, stage IIIb, stage IIIc were as follows: not reached, 221.2, 151.8, 88.5, 25.0, 19.0, and 13.0 months, respectively, for the entire cohort of patients (n = 1789). The corresponding 5-year survival rates were 86.7, 76.4, 64.9, 55.3, 29.9, 16.9, and 9.7 %, respectively. The survival rates significantly differed between the modified staging groups (p < 0.01). CONCLUSIONS: This modified staging system better discriminates the survival differences between stages than the seventh edition of the AJCC staging system for ESCC in Chinese patients.

Robotic portal resection for mediastinal tumours: a prospective observational study.

BACKGROUND: To demonstrate the effectiveness and feasibility of robotic portal resection (RPR) for mediastinal tumour using a prospectively collected database. METHODS: Data from 73 consecutive patients with mediastinal tumours who underwent RPRs were prospectively collected from August 2018 to April 2023. All patients underwent chest and abdominal enhanced computed tomography (CT) and preoperative multidisciplinary team (MDT) discussion. The patients were stratified into two groups based on tumour size: Group A (tumour size < 4 cm) and Group B (tumour size ≥ 4 cm). General clinical characteristics, surgical procedures, and short outcomes were promptly recorded. RESULTS: All of the cases were scheduled for RPRs. One patient (1/73, 1.4%) was switched to a small utility incision approach because of extensive pleural adhesion. Two patients (2.8%) converted to sternotomy, however, no perioperative deaths occurred. Most of the tumours were located in the anterior mediastinum (51/73, 69.9%). Thymoma (27/73, 37.0%) and thymic cyst (16/73, 21.9%) were the most common diagnoses. The median diameter of tumours was 3.2 cm (IQR, 2.4-4.5 cm). The median total operative time was 61.0 min (IQR, 50.0-90.0 min). The median intraoperative blood loss was 20 mL (IQR, 5.0-30.0 ml), and only one patient (1.4%) experienced an intraoperative complication. The median length of hospital stay was 3 days (IQR, 2-4 days). Compared with Group A, the median total operative time and console time of Group B were significantly longer (P = 0.006 and P = 0.003, respectively). The volume of drainage on the first postoperative day was greater in group B than in group A (P = 0.013). CONCLUSION: RPR is a safe and effective technique for mediastinal tumour treatment, which can expand the application of minimally invasive surgery for the removal of complicated mediastinal tumours.

Targeting pyruvate dehydrogenase kinase 1 overcomes EGFR C797S mutation-driven osimertinib resistance in non-small cell lung cancer.

Osimertinib, a selective third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), effectively targets the EGFR T790M mutant in non-small cell lung cancer (NSCLC). However, the newly identified EGFR C797S mutation confers resistance to osimertinib. In this study, we explored the role of pyruvate dehydrogenase kinase 1 (PDK1) in osimertinib resistance. Patients exhibiting osimertinib resistance initially displayed elevated PDK1 expression. Osimertinib-resistant cell lines with the EGFR C797S mutation were established using A549, NCI-H292, PC-9, and NCI-H1975 NSCLC cells for both in vitro and in vivo investigations. These EGFR C797S mutant cells exhibited heightened phosphorylation of EGFR, leading to the activation of downstream oncogenic pathways. The EGFR C797S mutation appeared to increase PDK1-driven glycolysis through the EGFR/AKT/HIF-1α axis. Combining osimertinib with the PDK1 inhibitor leelamine helped successfully overcome osimertinib resistance in allograft models. CRISPR-mediated PDK1 knockout effectively inhibited tumor formation in xenograft models. Our study established a clear link between the EGFR C797S mutation and elevated PDK1 expression, opening new avenues for the discovery of targeted therapies and improving our understanding of the roles of EGFR mutations in cancer progression.

The positive lymph node ratio predicts long-term survival in patients with operable thoracic esophageal squamous cell carcinoma in China.

BACKGROUND: Controversy exists concerning the optimal cutoff points for the positive lymph node ratio (PLNR) to predict overall survival. We aim to propose reasonable PLNR categories for the discrimination of the survival difference between groups. METHODS: We used data from two centers to establish a training (n = 1006) and a validation (n = 783) cohort. All of the patients underwent curative surgical treatment. Martingale residuals from a Cox proportional hazards regression model were used to determine the optimal cutoff points for PLNR to predict overall survival. The survival rate was calculated using the Kaplan-Meier method, and a log-rank test was used to assess the survival differences between groups. The results obtained from the training cohort were tested with the validation cohort at each step. RESULTS: We classified the patients into four revised nodal categories: R-pN0 (PLNR = 0), R-pN1 (0< PLNR ≤0.1), R-pN2 (0.1< PLNR ≤0.3), and R-pN3 (PLNR >0.3). Subgroup analysis for the pT2 and pT3 cases showed that the survival differences could be well discriminated between groups based on PLNR in both the training cohort and validation cohort. When we modified the current staging system using revised nodal categories (based on PLNR) instead of the AJCC nodal categories, the survival rate could also be easily distinguished between patients in different stages in both cohorts of patients. CONCLUSIONS: The survival rate of ESCC can be discriminated between four groups: PLNR = 0, 0< PLNR ≤0.1, 0.1< PLNR ≤0.3, and PLNR >0.3. Further studies are required to confirm these results.

Short-term outcomes of robotic lobectomy versus video-assisted lobectomy in patients with pulmonary neoplasms.

BACKGROUND: To explore whether robotic lobectomy (RL) is superior to video-assisted lobectomy (VAL) in terms of short-term outcomes in patients with pulmonary neoplasms. METHODS: From January 30, 2019 to February 28, 2022, a series of consecutive minimally invasive lobectomies were performed for patients with pulmonary neoplasms. Perioperative outcomes such as operation time, blood loss, dissected lymph nodes (LNs), surgical complications, postoperative pain control, length of postoperative stay in hospital, and total cost of hospitalization were compared. RESULTS: A total of 336 cases including 173 RLs and 163 VALs were enrolled. Baseline characteristics were comparable between groups. RLs were associated with shorter operation time (median [interquadrant range, IQR], 107 min [90-130] vs. 120 min [100-149], p < 0.001), less blood loss (median [IQR], 50 mL [30-60] vs. 50 mL [50-80], p = 0.02), and lower blood transfusion rate (3.5% vs. 9.8%, p = 0.02) compared with VALs. More LNs were harvested by the robotic approach (median [IQR], 29 [20-41] vs. 22 [15-45], p = 0.04). The incidences of conversion, major postoperative complications, extra analgesic usage, and postoperative length of stay were all comparable between the RL and VAL groups. As predicted, the total cost of hospitalization was greater in the RL group (median [IQR], $16728.35 [15682.16-17872.15] vs. $10713.47 [9662.13-11742.15], p < 0.001). CONCLUSION: RL improved surgical efficacy with shortened operative time, less blood loss, and more thorough LN dissection compared with VAL, compromised by higher cost.

Impact of the Number of Harvested Lymph Nodes on Long-Term Survival in Node-Negative Non-Small-Cell Lung Cancer: Based on Clinical Stage But Not Pathological Stage.

BACKGROUND: We aimed to investigate the impact of the number of harvested lymph nodes (LNs) on the overall survival (OS) and disease-free survival (DFS) of patients with clinical node-negative (cN0) non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: A total of 2247 patients with cN0 NSCLC between 2001 and 2014 were included. Scatter plots of hazard ratios from Cox proportional hazards models against the number of harvested LNs were created, and curves were fitted using a LOWESS smoother. Chow test was used to determine the cut-off points for the optimal number of harvested LNs. Long-term survival was compared between groups divided by the cut-off points. RESULTS: The increasing numbers of harvested LNs and N2 level LNs were independent factors favoring OS and DFS. Seventeen LNs and 10 N2 level LNs were determined as the optimal cut-off points. The patients with ≥17 harvested LNs had a better OS (P = .001) and DFS (P = .002), while the patients with ≥10 harvested N2 level LNs also had a better OS (P < .001) and DFS (P = .001). The increasing numbers of harvested LNs and N2 level LNs were independent prognostic factors associated with prolonged OS and DFS only in patients with clinical T2 (cT2) NSCLC. CONCLUSIONS: The increasing numbers of harvested LNs and N2 level LNs were associated with better OS and DFS in cN0 NSCLC patients that were suitable for lobectomies. At least 17 LNs and 10 N2 level LNs were required to be harvested, especially in cT2 patients.

Defining the learning curve of robotic portal segmentectomy in small pulmonary lesions: a prospective observational study.

Although robotic segmentectomy has been applied for the treatment of small pulmonary lesions for many years, studies on the learning curve of robotic segmentectomy are quite limited. Thus, we aim to investigate the learning curve of robotic portal segmentectomy with 4 arms (RPS-4) using prospectively collected data in patients with small pulmonary lesions. One hundred consecutive patients with small pulmonary lesions who underwent RPS-4 between June 2018 and April 2021 were included in the study. Da Vinci Si/Xi systems were used to perform RPS-4. The mean operative time, console time, and docking time for the entire cohort were 119.2 ± 41.6, 85.0 ± 39.6, and 6.6 ± 2.8 min, respectively. The learning curve of RPS-4 can be divided into three different phases: 1-37 cases (learning phase), 38-78 cases (plateau phase), and > 78 cases (mastery phase). Moreover, 64 cases were required to ensure acceptable surgical outcomes. The total operative time (P < 0.001), console time (P < 0.001), blood loss (P < 0.001), and chest tube duration (P = 0.014) were reduced as experience increased. In conclusion, the learning curve of RPS-4 could be divided into three phases. 37 cases were required to pass the learning phase, and 78 cases were needed to truly master this technique.