VATS has been widely used to diagnose and treat various thoracic diseases, such as diseases of the lung, mediastinum, pleural membrane, and esophagus [16–20]. Most conventional VATS procedures use portals. Rocco et al. first reported uniportal pulmonary wedge resection in 2004 [21], and the indications for this procedure have since expanded to include many thoracic diseases, including those in the pleural membrane, mediastinum, and lung [3]. In 2011, Gonzalez et al. reported uniportal VATS, a technique that has been further promoted in recent years [22]. Currently, there is no definite age cutoff for elderly patients in clinical research involving these procedures. A review of the relevant literature revealed four various age cutoffs used in elderly patients: 65 years old, 70 years old, 75 years old, and 80 years old [23–26]. Searches of domestic and foreign literature regarding VATS in the elderly showed that relatively more publications used ≥ 70 years old as the age cutoff. Thus, the age of elderly patients was set to ≥ 70 years old in the present study. We searched databases such as PubMed and EMBASE, but could not identify any English language report on the application of uniportal VATS in elderly patients (≥ 70 years) with NSCLC. The present study was the first to show that uniportal VATS is safe and effective for treating elderly patients with NSCLC, and that uniportal VATS causes less pain and confers less blood loss than multiportal VATS.
Uniportal VATS is a relatively new surgical modality, so conversion to thoracotomy is inevitable during its initial phase of adoption [9, 10, 27]. Common causes of conversion to thoracotomy include pleural adhesions, tumor invasion, massive intraoperative hemorrhage, and injury of vital structures. Chung et al. conducted a retrospective analysis of 90 cases of uniportal VATS and found that conversion to thoracotomy occurred in 10 cases (11.1%) due to adhesions, tumor invasion, and tracheal injury [27]. Shen et al. reported 100 cases of uniportal VATS and found that one patient (1%) had conversion to thoracotomy due to massive hemorrhage [9]. Yameen reported 55 patients who had undergone uniportal VATS, five of whom (9.1%) had conversion to thoracotomy due to pleural adhesions [10]. In the present study, one patient in each of the two groups had conversion to thoracotomy. The patient in the uniportal VATS group had pleural adhesions that occurred in the early stage of uniportal VATS, and the patient in the multiportal VATS group had massive intraoperative hemorrhage. The field of vision in uniportal VATS is closer to that in thoracotomy, which allows separation of the adhered pleural membranes. No subsequent conversion to thoracotomy due to adhesions was required. With advancements in surgical techniques, iatrogenic tissue injuries can be treated using uniportal VATS. Conversion to thoracotomy is required in cases of massive intraoperative hemorrhage to ensure the safety of the procedure.
The extent of lymph node dissection and the number of lymph nodes dissected are important parameters for assessing whether radical surgery is feasible as cancer treatment [2]. These parameters also serve as an important reference for accurate postoperative staging and prognosis [2]. The combination of lobectomy and systemic lymph node dissection is the standard surgical treatment for NSCLC [2]. The guidelines developed by the National Comprehensive Cancer Network (NCCN) recommend dissection of three or more mediastinal lymph node stations, and the total number of lymph nodes dissected should be at least 12 [28]. In the present study, the number of lymph nodes, lymph node stations, and N2 lymph nodes dissected in the uniportal VATS group did not differ from the equivalent numbers in the multiportal VATS group. In addition, the guidelines were met [28], indicating that uniportal VATS is safe and feasible for use in lymph node dissection.
Advancements and refinements in thoracoscopic technique have allowed minimally invasive thoracic surgery. Reduction of iatrogenic trauma and enhanced recovery after surgery (ERAS) have become the major directions for future development of thoracic surgery. The concept of ERAS necessitates collaboration across multiple disciplines, such as anesthesia, nursing, and surgery. It involves preoperative education, preoperative preparation, keeping patients warm, anesthetics with a shorter half-life, restrictive intraoperative fluid replacement, and enabling mobility early after surgery [29]. ERAS involves cutting-edge techniques and concepts, with the core values of optimizing perioperative management and care measures, reducing complications and stress responses, and accelerating recovery. A study by Huang et al. showed that adopting ERAS during the perioperative period of uniportal VATS can alleviate postoperative pain, shorten postoperative hospital stays, and reduce the duration of chest tube placement [29]. In the present study, ERAS was implemented in the perioperative period. None of the patients in either group died within 30 days of surgery. In addition, postoperative complications after 30 days were mostly minor. One patient in each of the uniportal VATS and multiportal VATS groups had serious complications, which were cured after active treatment.
Long-term patient prognosis is the fundamental criterion for evaluating whether a novel approach to lung cancer surgery is superior to the conventional approach. Uniportal VATS was first reported in 2011 [22], while wide adoption in major medical centers began in 2014 [5–14]. According to our searches, most existing reports on uniportal VATS focus on short-term outcomes [5–14], and few have evaluated medium-term outcomes [13]. Zhao et al. reported 3-year overall survival in patients with NSCLC aged ≥ 60 years [13], including 73 who underwent uniportal VATS and 56 who underwent multiportal VATS. The results showed that 3-year overall survival was not significantly different between the two groups [13]. This was consistent with the results of the present study, which showed that 3-year overall survival and disease-free survival were similar in the two groups.
Using the propensity score matching (PSM) method [30], a propensity score is calculated for each research subject. Individuals from the control group with the same or similar propensity scores as those in the treatment group are then selected and matched. The aim of PSM is to balance the covariates between the groups. Using this method, each propensity score is treated as an independent variable that is evenly distributed between the control and treatment groups. This method is used to achieve a similar effect to randomized controlled trials and minimize study bias. PSM is now widely used in retrospective studies and non-randomized clinical trial data [30].
Several limitations of this study must be considered. The present study was a retrospective analysis in which PSM could only balance the observable variables. The impact of potential unknown factors on the observation endpoints could not be corrected. Multi-center randomized controlled trials are needed in the future to elucidate the impact. Our institution first adopted UVATS in 2015, so long-term follow-up data are lacking, which was a limitation of the study. Thus, we eagerly await confirmation of the short- and medium-term effectiveness of the two surgical modalities in multi-center prospective randomized controlled trials.