This study retrospectively investigated the surgical outcomes of LG/RG following chemotherapy and compared them with those of OG. The results showed that LG/RG following chemotherapy is safe and feasible owing to its good short-term outcomes.
The development of new anticancer drugs and highly effective regimens has enabled remarkable tumor shrinkage with chemotherapy, whereby some patients with stage IV gastric cancer demonstrating a good response to chemotherapy have been able to undergo curative resection followed by long-term survival . The current literature demonstrates that the so-called conversion surgery for unresectable stage III or stage IV gastric cancer is associated with longer survival than chemotherapy alone. On the other hand, NAC has been proven to increase the R0 resection rate and reduce lymph node metastases compared with surgery alone . The European Organization for Research and Treatment of Cancer randomized trial illustrated that the R0 dissection rate in the NAC group was significantly higher than that in the surgery-alone group and that the NAC group had fewer lymph node metastases .
LG is accepted as being more effective than conventional open surgery and is commonly used to treat clinical stage I gastric cancer in accordance with the recent technical and instrumental improvements. Even for locally advanced gastric cancer, the technical safety of LG has been demonstrated in a randomized phase II study. A large phase III trial, KLASS-02, reported that LG with D2 lymphadenectomy was associated with lower postoperative complication rates, faster recovery, and less pain compared with OG. Moreover, laparoscopic surgery also offers benefits in gastrectomy for locally advanced gastric cancer after neoadjuvant chemotherapy, such as better postoperative safety and adjuvant chemotherapy tolerance, compared with conventional open surgery. A randomized controlled study conducted in east Asia confirmed that the technical feasibility of gastrectomy with D2 lymphadenectomy performed by laparoscopy was comparable to that of OG . For patients with advanced gastric cancer who have not undergone preoperative chemotherapy, RG with D2 lymphadenectomy is feasible and safe for the treatment of advanced gastric cancer in terms of the lower incidence and severity of its complications . Robot-assisted D2 gastrectomy is also technically reasonable, although its long-term outcomes are yet to be evaluated in prospective studies in Japan.
In the current study, patients in the LG/RG group had significantly lower intraoperative blood loss and better postoperative recovery compared with the OG group, with previous studies reporting similar findings for patients with advanced gastric cancer who had not undergone NAC and conversion surgery [3, 20]. The findings of the current study show that the advantages of LG/RG remain the same for patients with advanced gastric cancer who undergo preoperative chemotherapy. The precise operative techniques involved in LG/RG help to minimize intraoperative blood loss. Because intraoperative blood loss is associated with the prognosis of gastric cancer [21, 22, 23]. LG/RG may help improve the prognosis for some patients.
No significant differences were observed between the postoperative complication rates in the LG/RG (0 patients, 0%) and OG groups (5 patients, 13%) (P = 0.1) in this study, a finding which was consistent with the morbidity rates about 10% reported in previous studies on patients who underwent open D2 gastrectomy following NAC and conversion [3, 8]. The incidence of surgical complications in the LG/RG group can be considered low.
Chemotherapy causes tissue fibrosis, tissue edema and necrosis and destroy the anatomical dissection plane. As the result, these reactions may interfere with the surgical procedure and makes surgery more difficult, therefore, increase postoperative complication rates. Therefore, more operative blood loss has been observed in patients who have previously undergone neoadjuvant therapy, in whom it was harder and more tedious to stop the bleeding. D2 lymphadenectomy after neoadjuvant chemotherapy is more risky than D2 lymphadenectomy without preoperative treatment. Such issues may be resolved by LG/RG because this procedure allows for visual magnification, better exposure, and more delicate maneuvers of organs, vessels, and nerves [24, 25]. Operative hemorrhage can be easily induced by fibrosis and tissue edema, although an ultrasonic knife plays an important role in hemostasis. No postoperative complications and mild intraoperative bleeding were observed in this study. Although the operative time tends to be longer, LG/RG should be considered for patients who have undergone preoperative chemotherapy.
Previously, patients who received preoperative chemotherapy underwent open surgery. However, as laparoscopic and robotic surgery became increasingly adopted, the indication for LG/RG was expanded to pretreatment cases. All procedures were performed by qualified surgeons certified by the ESSQS of the JSES who had adequate experience. It is therefore difficult to state that RG/LG itself is effective in all cases of preoperative chemotherapy. LG performed by credentialed surgeons was surgically safe and feasible for patients with advanced gastric cancer compared with conventional OG .
This study had several limitations. First, the indications of the preoperative chemotherapy were different for patients undergoing NAC and conversion surgery. Hence, these two should be investigated individually in the future. This study focused on short-term results based on the surgical method; therefore, both patients undergoing NAC and conversion surgery were included. Other limitations of this study were the limited sample size, the retrospective nature, and the lack of randomization in the two treatment arms. Finally, only the short-term outcomes were examined, and the long-term outcomes remain to be investigated.