This study successfully demonstrated the advantage of TLTG compared with matched LATG in terms of lower grade I pulmonary complication rate and better QoL of dysphagia, pain, or eating during postoperative 1 year. Retrospective studies cannot usually be sensitive enough to analyze parameters such as minor complications or changes in QoL and may provide false-negative or biased results. This study utilized prospectively collected complication data and QoL cohort, both of which had been recruited independently of the original purpose of this study. We believe that our study can provide less biased and more sensitive results than other unmatched retrospective studies.
The postoperative pulmonary complication was reported as one of the greatest risk factors for postoperative mortality in gastric cancer patients [12, 23, 24]. In addition, total gastrectomy was an independent risk factor for pulmonary complications following laparoscopic gastrectomy [13]. Previous meta-analysis comparing LATG with open TG reported that LATG was associated with a significant reduction in medical complications, but a contribution from respiratory complications was not significant [25]. Other retrospective study limitedly demonstrated the lower incidence of pulmonary complications in the LATG group than in the OTG group, only in patients aged over 65 [26]. On the other hand, previous studies comparing TLTG and LATG mainly focused on anastomotic complications, and rarely addressed issues with pulmonary complications [1-5]. Upper abdominal incision causes decreased pulmonary function more frequently than lower abdominal surgery [11, 27, 28]. The mini-laparotomy wounds of the LATG are inevitably larger and located closer to epigastrium than those of TLTG. In addition, the LATG group had a higher score of STO22 pain than the TLTG group (Figure 2b). The larger incisions in the epigastrium and worse pain score may explain the limited movement of the diaphragm and deep breathing, followed by a decreased pulmonary function in the LATG group.
This is the first study comparing QoL over consecutive multiple time points during the year after operation between TLTG and LATG groups. Previous studies reported better QoL scores of C30 pain and STO22 dysphagia in the TLTG group than in the LATG group, but only investigated the QoL at a single time point and did not include OG25, more sensitive in evaluating QoL after total gastrectomy [18, 29]. In this study, TLTG only determined a better QoL for dysphagia, eating, or odynophagia. DST without purse-string suture was first introduced in 1994 as an easier alternative technique to single stapling technique (SST), but has a risk of high postoperative anastomotic stenosis rate [30, 31]. To overcome this limitation, hDST was proposed, but previous studies still reported high rates of stenosis (7.3%-21%) and leakage (4.9%-9.9%) [30, 32, 33]. Since 2013, SNUH started TLTG with intracorporeal hDST using needle-guided anvil fixation. Our institution standardized this technique with repeated discussion and consensus among surgeons from the first case, by which all complications were not different among operators (P=0.947, supplementary table 4). Many previous reports of hDST techniques revealed that it was difficult to tighten the entry hole of the anvil spike at the esophageal stump [32, 33]. On the other hand, the anvil spike located in the middle of the esophageal wall still might have a risk of double stapling across the efferent loop of the Roux limb [34]. As a simple modification, we pulled out the anvil in the medial esophageal wall using the guiding thread, which led to the smallest entry hole for the anvil spike, and secured hDST with a single stapling site completely toward the efferent loop and double stapling site toward the blind loop of the jejunal Roux-limb. In this study, the low rates of early and delayed anastomotic complications demonstrated the safety and efficacy of our modified hDST. In addition, the TLTG group with hDST showed better QoL of dysphagia and eating restriction than the LATG group. Adhesion after initial abdominal surgery occurs within the postoperative 1 year and may last for several years. [35-38]. Adhesion tissue were reported to contain nerve conducting pain stimuli [39]. Since, fixed adhesion can compromise the lumen of bowel, and filmy adhesion allowing movement between the bowel and surrounding structure can elicit nonobstructive abdominal pain, patients with peritoneal adhesion can manifest vague to highly distressing pain [40]. The unpredictability of abdominal pain caused by adhesions significantly impacts on a patient's emotions and social life, including fear for eating [41]. We assume that less exposure of the peritoneal cavity, especially the upper abdomen, may induce less adhesion around the anastomosis or provide better recovery of bowel movement [42-44]. Taken together, not only the possible different exposure of peritoneal cavity but also the different anastomotic technique may explain the different QoL in this study.
In this study, we analyzed the CUSUM and learning curve based on the CCI, rather than operation time. In the past, standardizing multiple complications into a single variable seemed impossible due to the absence of adequate methods. However, through introducing CCI, one representative complication index per patient can be estimated. To our knowledge, this is the first study to evaluate the learning curve using CCI. Because CCI is directly related to the patient’s outcome, this approach to the learning curve is more reasonable and intuitively understandable, than previous ones based on operation time. Our study can imply that simple effort to shorten the operation time may be less meaningful during the adoption and stabilization of a novel and complex surgical technique.
This study has some limitations. Firstly, since LATG and TLTG were performed in different time periods, there might be a discrepancy in laparoscopic surgical skills or chronologic changes in clinicopathologic factors between the TLTG and LATG groups. This time trend was inevitable when comparing old and new surgical techniques in retrospective analysis. To minimize this bias, we included all patients in the TLTG group from the first case, and all patients in the LATG group during the same period of TLTG for analysis. Besides, all surgeons at SNUH started performing TLTG in a similar period. Secondly, the sample size for QoL evaluation between TLTG and LATG was limited. In SNUH, an independent prospective cohort study was conducted to analyze only QoL, regardless of the purpose of the present study. Of these prospectively collected cohorts, we could separately selected 84 patients who met the inclusion criteria of the current study, not based on specific criteria or intentions. Therefore, the independence of QoL data can be the unbiased evidence for current study. Despite the small sample size of QoL data, this is the first study comparing QoL over consecutive multiple time points during the year after operation between TLTG and LATG groups. Considering that a small sample size usually has a risk of yielding false-negative or low sensitivity results, the significant difference in QoL between TLTG and LATG, even in the multivariate analysis, still can be valuable. However, large-scale prospective RCTs are necessary to validate more robust evidence for QoL differences.
In conclusion, TLTG with hDST were associated with reduced pulmonary complications and better QoL in terms of dysphagia, pain, eating, and odynophagia than LATG for patients with clinical stage I gastric cancer.