Older patients have a poor preoperative pulmonary function, and an increased risk of postoperative pulmonary complications. The risk of pulmonary complications in patients with FEV1 less than 2L and less than 1L is moderate and high, respectively. PF test criteria for lobectomy are a forced expiratory volume in 1 second (FEV1) > 1.0L and maximum voluntary ventilation (MVV) > 40% of predicted [7–9]. In this study, the older patients had poor pulmonary function performance as compared to their counterparts, which indicated that the postoperative risk complications were higher with older patients (≥ 70 years of age) as compared to younger patients (≤ 70 years of age). The ERAS model was first proposed by the Danish surgeon Kehlet in 1997[39–41]. It refers to the comprehensive use of a series of optimization measures supported by evidence-based medicine during the perioperative period, including multidisciplinary collaboration of surgery, anesthesia, nursing, and nutrition, to optimize the clinical pathway for perioperative management, in order to reduce the perioperative stress response (i.e., physiological and psychological traumatic stress) and postoperative complications in surgical patients with the aim of achieving the best health status and rapid recovery with minimal cost. Since the ERAS model was successfully applied for the first time in gastrointestinal surgery, this concept has now been adopted in neurosurgery, thoracic surgery, and other surgical fields [39–41]. Studies have shown that under the ERAS protocol, it is possible to effectively reduce surgical trauma and postoperative stress response, shorten the length of hospitalization, and promote patient recovery in the perioperative period of VATS lobectomy[39–41]. The results of our study revealed that postoperative complications and severe complications in the elderly group were similar to that of the nonelderly group. This suggests that although the preoperative pulmonary function of elderly NSCLC patients is worse than the non-elderly patients, VATS lobectomy allows elderly NSCLC patients to have similar short-term outcomes as non-elderly patients, thus indicating the safety of VATS lobectomy for the treatment of elderly NSCLC patients.
Postoperative complications after VATS may adversely affect the long-term outcomes [7–9]. The surgery may cause a systemic inflammatory reaction, and the level of inflammatory factors and C-reactive protein will increase [7–9]. Postoperative complications, especially major complications, may exacerbated Inflammation and immunosuppression [7–9]. The perioperative stress response will inhibit the activity of natural killer cells, increase tumor burden, inhibit endogenous mediators, lead to the downregulation of effector lymphocytes and regulatory pathways, and put the body in a state that promotes tumor growth [7–9]. Stress and inflammation caused by major postoperative complications may cause the residual cancer cells to grow and proliferation, which will have an adverse effect on long-term prognosis [7–9]. In this study, the postoperative 30-day complication rate and the rate of serious complications were similar in both groups, which may also be one of the reasons for the similar prognosis of the two groups.
The results of a prospective study showed that the local recurrence rates of early stage NSCLC patients underwent lobectomy are significantly lower than sublobar resection, and the survival rate is significantly higher than sublobar resection. Therefore, the current standard surgical procedure for early stage NSCLC is still anatomical lobectomy. Sublobar resection is currently still in clinical research. Two prospective multicenter randomized controlled trials comparing early lung cancer lobectomy with sublobar resection have been completed, and there are reports of short-term outcomes. Differences in surgical complications or mortality are statistically significant and are currently waiting for long-term follow-up results.
Conversion to thoracotomy is an inevitable phenomenon during VATS lobectomy [47–53]. The overall conversion to thoracotomy rate of the 218 patients included in this study was 1.7%, and the two age groups had similar conversion to thoracotomy rates. A study by Sawada showed that the most important cause of conversion to thoracotomy was the calcification of lymph nodes and their adhesion to pulmonary vessels with subsequent difficult separation . This accounted for 60% of the conversion to thoracotomy rates in our study. In contrast, a study demonstrated that the most common cause of conversion to thoracotomy was vascular injury leading to uncontrollable bleeding, and vascular injury is a common cause of conversion to thoracotomy in minimally invasive surgery such as thoracoscopic esophagectomy and laparoscopic gastrectomy . Although conversion to thoracotomy can cause prolonged operation duration, increased length of postoperative hospital stay, and increased postoperative pain, it does not cause serious complications or death.
It is common for elderly NSCLC patients to have comorbidities, and the impact of comorbidities on elderly NSCLC patients is getting more and more attention. Charlson Comorbidity Index (CCI) and SCS are the two commonly used methods to assess comorbidities. Compared with CCI, SCS can more accurately assess the impact of comorbidities on the prognosis of NSCLC patients. Through a prospective study of 136 elderly NSCLC patients, Colinet et al. showed that the median survival of patients with a score of ≤ 9 was longer than those with a score of > 9, suggesting that a SCS of > 9 is an unfavorable prognostic factor in elderly NSCLC patients , which is consistent with the results of this study. In the SCS scheme, smoking accounts for a high proportion (weighting = 7) of the total score, as smoking has been confirmed to be closely related to the incidence of common comorbidities in elderly patients such as cardiovascular and respiratory diseases.Therefore, the SCS method provides a more objective and comprehensive assessment of comorbidities in NSCLC patients and is more suitable for studying the impact of comorbidities on the prognosis of NSCLC patients.
VATS lobectomy is mainly performed through multiple incisions, predominantly three incisions, and the three-incision method was also adopted in this study. Minimally invasive surgery is one of the growing developments of surgery. At present, single-incision endoscopic surgeries such as single-incision appendectomy and single-incision cholecystectomy are widely performed [55, 56]. Since Gonzalez’s first report of single-incision VATS lobectomy , retrospective studies have shown that single-incision VATS lobectomy is safe and feasible [58–62]. In 2016, a randomized controlled trial comparing single-incision versus multi-incision VATS lobectomy revealed that the two groups of patients demonstrated similarities in short-term outcomes such as analgesic medication use, duration of chest tube placement, length of postoperative hospital stay, and incidence of complications . However, there are few reports on long-term outcomes of single-incision VATS lobectomy in the treatment of NSCLC. The key to evaluating a new minimally invasive tumor surgery is the long-term survival rate. Consequently, we should refrain from performing single-incision VATS lobectomy untill sufficient research progress has been made.
The present study suffered from numerous limitations since the study was a single-center retrospective analysis with limited sample size; thus, the possibility of selection bias is inevitable.