Since 1881, when Billoth performed the first gastric cancer surgery, surgical treatment has been the basic method and the main means of gastric cancer treatment. Surgery is the only possible way to cure gastric cancer, so it has naturally become the first choice for gastric cancer treatment. However, it must be clear that the great progress made in gastric cancer treatment in recent years is not only achieved by surgery alone, but should be attributed to the comprehensive treatment based on surgery. The goal of surgical treatment for gastric cancer is to cure the tumor, prolong the patient’s life and improve the patient’s quality of life. To achieve this goal, three basic principles of tumor treatment should be followed, namely safety, curative and functional principles.
The principle of radicality is the most important part of the surgical procedure for gastric cancer and is the core part of it. Radical gastric cancer surgery is to adequately remove gastric tumor and enough potentially invaded gastric tissues, and to clear regional lymph nodes, etc. The surgery must follow some basic operation principles, such as the principle of whole tumor removal, the principle of no contact and the principle of preventing the spread of medically derived tumor, etc. The requirements of radical surgery for early gastric cancer and progressive gastric cancer are different.
I. Basic principles of radical surgery for gastric cancer
1. Whole block resection
In other words, the primary gastric tumor, the regional lymph nodes and the affected adjacent organs should be removed in one block. There are still controversies at home and abroad about the amount of resected gastric tissues and the scope of regional lymph node dissection. In general, it is considered that 4-6 cm of gastric tissue should be removed from the tumor margin. In the specific operation, the different subdivisions of gastric cancer should be considered, whether the tumor is located in the gastric sinus or in the gastric body or fundus, and whether it is located in one area or more than one subdivision. If the gastric tumor is located in the gastric body or fundus, or the size exceeds one partition, total gastrectomy is advocated to ensure the radical nature of the operation. At the same time, the general pathological type and histological typing of the tumor should be considered, and the amount of gastric tissue to be removed should be flexible. If necessary, intraoperative frozen section should be performed to confirm. The lymph node dissection of gastric cancer is indicated by D (dissection), which includes 5 different grades, i.e. D0 to D4. D0 surgery only removes gastric cancer tissue without lymph node dissection; D1 surgery dissects the lymph nodes in the first station of the perigastric region (N1); D2 surgery dissects the lymph nodes around the gastric artery on top of D1, i.e. dissects the lymph nodes in the second station (N2); D3 surgery dissects the lymph nodes in the abdominal trunk on top of D2. The lymph nodes of the abdominal trunk (N3) are cleared on the basis of D2; the lymph nodes around the abdominal aorta (D4) are cleared on the basis of D3. The perigastric vessels should be severed from the root ligation, and the lymph nodes should be cleared to D > N.
2.Prevent medical tumor dissemination
The concept of prevention of medical origin tumor dissemination should be strictly established during the whole operation process from the incisional approach, including the entry of abdominal exploration and surgical resection to the closure of abdomen and suturing of skin, and should be implemented and reflected in each specific operation step.
(1) Incision selection and protection
The selection of surgical incision for gastric cancer should consider the site, size and possible invasion of tumor.
The incision should be close to the resection site, large enough to have good exposure and avoid squeezing the tumor. Generally, the upper mid-abdominal incision is commonly used, and after incision of peritoneum
After incision of the peritoneum, the incision should be protected with multiple layers of gauze pads and therapeutic towel sutures. At present, plastic collars specifically designed to protect the incision have been marketed and used clinically with good results.
The results are good. The gloves are changed when the abdomen is closed. After suturing the peritoneum, the incision should be flushed with distilled water several times.
(2) Isolation of tumor
That is, intraoperative measures are taken to isolate the tumor from the body for the possible invasion and metastasis pathways of gastric cancer. In order to avoid the shedding and metastasis of cancer cells, when the gastric cancer invades the plasma membrane surface of the gastric wall, applying medical bio-glue on the involved area of the plasma membrane surface is an effective method; or covering it with gauze suture or wrapping it with free large omentum is also effective. In order to prevent medical hematologic and lymphatic spread that may be triggered by surgical operations, sutures can be ligated along the greater and lesser curves of the stomach respectively to block the gastric vessels, and then other operations can be performed to separate them.
(3) Treatment of intraoperative abdominal exfoliated tumor cells
Positive detection of abdominal exfoliated cancer cells is an independent poor prognostic factor, and killing the exfoliated cancer cells is an effective measure to prevent peritoneal metastasis. Therefore, adequate killing of abdominal exfoliated cancer cells is an important part of the concept of radical surgery for gastric cancer and one of the basic requirements of radical surgery for gastric cancer. After whole block resection of tumor and its regional lymph nodes, a certain amount of time should be spent on peritoneal lavage. After repeatedly rinsing the abdominal cavity with distilled water, it is better to lavage the abdominal cavity with carboplatin distilled water solution or chlorhexidine solution at 43 ℃.
II. Radical principles of early gastric cancer treatment
First of all, the biological behavioral characteristics of early gastric cancer should be correctly understood. The concept of early gastric cancer was first proposed by Japanese scholars and gradually recognized, which is mainly based on the depth of lesion infiltration, that is, as long as the depth of lesion is located in mucosal layer or submucosal layer, it is considered early gastric cancer. It has nothing to do with the size of tumor or the presence of lymph node metastasis. It must be recognized that although the metastasis rate of early gastric cancer is lower compared with that of progressive gastric cancer, there is also regional lymph node metastasis, which is often overlooked by clinicians. In a 10-year follow-up study of early gastric cancer, Japanese scholars found that the lymph node metastasis rate of mucosal cancer was 1%-3%, and the lymph node metastasis rate of submucosal cancer was 11%-20%. The 5-year survival rate of early gastric cancer without lymph node metastasis was as high as 9913%, while the 5-year survival rates of early gastric cancer with lymph node metastasis at station 1, station 2 and station 3 were 9618%, 7217% and 0%, respectively. Therefore, radical surgery is required for all early gastric cancers considered to have lymph node metastasis. For mucosal cancer, D1 surgery, D2 surgery for submucosal cancer, and total gastrectomy for superficial extensive or multiple early gastric cancers are performed. Endoscopic mucosal resection (EMR) is performed only for mucosal cancers less than 3 cm in diameter without lymph node metastasis.
The radical principle of combined organ resection
From the perspective of embryonic development, the stomach, liver, pancreas and spleen all develop from the differentiation of the foregut and are wrapped in the same mesentery, and their lymph node drainage must be inseparably linked together, therefore, the resection of combined organs of gastric cancer is actually more in line with the principle of whole-block resection. Therefore, combined visceral resection of gastric cancer is actually more in line with the principle of whole-block resection. The pathways of lymph node metastasis of gastric cancer strictly in the order of stations 1, 2 and 3 do not constitute the majority of cases, and there are often jumping metastases. Combined organ resection must pay attention to the safety of surgery. In recent years, with the improvement of anesthesia level, perioperative monitoring ability and postoperative nutritional support, the success rate and survival rate of combined visceral resection for gastric cancer have been improved, and the operative mortality rate and complication rate have been significantly reduced, so combined visceral resection is relatively safe.
(1) Combined liver resection for gastric cancer
There are two ways for gastric cancer to invade liver metastasis: one is the tumor in the upper and middle part of stomach, which directly infiltrates the left lobe of liver due to its location next to liver, and the other is hematogenous metastasis to liver through portal vein system. In the former case, partial resection of the liver lobe is performed with good results. The latter needs to be determined on a case-by-case basis. Unlike liver metastasis of colorectal cancer, liver metastasis of gastric cancer are mostly diffuse cancer foci, and less often isolated cancer foci, which are often accompanied by peritoneal dissemination and extensive lymph node metastasis. The indications for hepatic resection are still controversial, but it is generally believed that those with better differentiation type of gastric cancer, liver metastases should preferably be confined to one lobe, single cancer foci within 5 cm in diameter, without peritoneal dissemination, extensive lymph node metastases and other distant metastases, and the liver margin should be more than 1 cm from the tumor to ensure complete resection.
(2) Gastric cancer combined with pancreaticoduodenectomy
In the past, it was thought that gastric cancer invading the pancreas could not be resected, but in fact, as long as gastric cancer does not invade the superior mesenteric vein and portal vein, combined pancreaticoduodenectomy is still an option if available. However, the indications for combined pancreaticoduodenectomy for gastric cancer should be strictly controlled, including.
① invasion of pancreatic head by gastric cancer.
②No6 lymph node metastasis and infiltration of the pancreatic head.
③Gastric cancer invading the duodenum more than 2 cm above the pylorus ;
(4) Gastric cancer invading the lower part of the common bile duct.
(3) Gastric cancer combined with splenectomy
Since the tumor of gastric body and gastric base can easily metastasize to the splenic portal and the lymph nodes adjacent to the splenic artery, theoretically speaking, it is necessary to combine splenectomy and even partial pancreatic tail resection for radical treatment. On the issue of whether to combine splenectomy with radical treatment of gastric cancer, there have been differences. Opponents believe that combined splenectomy cannot prolong postoperative survival and improve survival rate, while splenoprotective surgery can achieve the opposite effect. Proponents believe that only combined splenectomy can remove group No10 and 11 lymph nodes in their entirety; moreover, recent studies have shown that the spleen plays a positive immune role only in the early stage of tumor, while in the progressive stage of tumor, especially in the advanced stage, the positive immune role of the spleen is increasingly weakened and replaced by a negative immune role that is mainly suppressive, and splenectomy may improve the immune status of the body. Therefore, as long as there is no distant metastasis and the systemic condition permits, combined splenectomy should be performed for upper middle stomach cancer with direct spleen invasion or lymph node metastasis next to splenic hilar or splenic artery. Of course, due to improper operation, the spleen may be accidentally injured during radical treatment of gastric cancer, and joint splenectomy may also be forced.
(4) Combined transverse colectomy for gastric cancer
Since the greater curvature of the stomach is adjacent to the transverse colon and its mesentery, the tumor on the side of the greater curvature of the stomach at the progressive stage is very likely to invade the transverse colon and its mesentery, and may also infiltrate the middle colonic artery and its branches, so according to the principle of radical gastric cancer surgery, combined transverse colectomy is required. The scope of resection is the same as that of the primary transverse colon cancer. Although the combination of transverse colon and its ligament resection increases the invasiveness and difficulty of surgery, it can significantly improve the prognosis. For those who cannot perform radical resection, transverse colectomy should also be performed palliatively.
IV. Radical principles of laparoscopic gastric cancer surgery
Laparoscopic radical surgery for gastric cancer is a new gastric surgery method that has been gradually developed in recent years. Laparoscopic surgery has the advantages of less local trauma, less systemic reaction, faster postoperative recovery, shorter hospital stay and fewer complications, which is well liked and welcomed by surgeons and patients. Laparoscopic radical gastric cancer surgery is divided into three categories: complete laparoscopic surgery, laparoscopic-assisted and hand-assisted laparoscopic surgery. Completely laparoscopic surgery means that the separation, resection or reconstruction of the digestive tract of the stomach is done laparoscopically. Laparoscopically assisted means that the separation of the stomach is done laparoscopically and the specimen of the stomach is removed through a small adjuvant incision, through which gastrointestinal reconstruction can also be performed and even assisted lymph node dissection. Hand-assisted laparoscopy has the advantages of laparoscopic surgery and open surgery, while having the sense of touch facilitates the location of the lesion, helps to reveal and separate it, and shortens the operative time compared to complete laparoscopy. Laparoscopic surgery for gastric cancer, whether it is gastric freeing, resection or reconstruction, has many operation steps and operation planes, which makes the surgery more complicated and demanding. The main challenges faced intraoperatively are intraoperative bleeding, contamination of the abdominal cavity with gastric contents and reconstruction of the digestive tract. It is generally believed that to be competent in laparoscopic radical gastric cancer surgery, one must have a certain amount of experience in moderately difficult laparoscopic surgery (such as laparoscopic cholecystectomy or laparoscopic colorectal surgery) based on specialized training in laparoscopy. He also has extensive experience in open radical gastric cancer surgery. The selection of indications for radical laparoscopic gastric cancer surgery relies heavily on the laparoscopic surgical experience of the surgeon. Early gastric cancer is a better indication for laparoscopic surgery. For small and superficial anterior wall without submucosal infiltration, wedge resection of the stomach is feasible, but only with accurate intraoperative gastroscopic localization and D1 surgery for other early gastric cancers. Radical distal major gastrectomy, proximal major gastrectomy or total gastrectomy is feasible for early progressive gastric cancer. Laparoscopic radical gastric cancer surgery is still in the exploratory stage, and there are still controversies at home and abroad. The main focus is on the following aspects.
(1) whether it can achieve the same radicality as open surgery, including the completeness of tumor resection and reliability of lymph node dissection.
(2) The effect of CO2 pneumoperitoneum on intraoperative tumor dissemination, postoperative recurrence and metastasis.
(3) the presence or absence of cancer cell implantation in the puncture trocar hole.
Laparoscopy has the advantage of magnification effect and ultrasonic knife has the advantage of good hemostasis effect and light damage to surrounding tissues, which can achieve complete naked vascularization and ensure ligation from the root, severance of blood vessels of the stomach and complete lymph node dissection. At the same time, the laparoscopic grasping forceps expose only a small amount of tissue for lifting and grasping, which basically does not squeeze the tumor tissue. The specimen is wrapped in plastic bags with open ends when removed to avoid small incisional cancer implantation. These measures can ensure radical resection of laparoscopic gastric cancer and avoid small incisional cancer implantation. Laparoscopic gastric cancer surgery has been proved to be safe and feasible, and is in accordance with the principles of oncological surgery operation. It has been continuously shown that the immediate and long-term efficacy of laparoscopic gastric cancer surgery is comparable to that of open surgery, while laparoscopic surgery has less bleeding, earlier resumption of feeding and shorter hospital stay. Therefore, it can be believed that, like open surgery, the radical results of laparoscopic gastric cancer surgery can be fully guaranteed with the increasing proficiency and perfection of laparoscopic techniques of the operators.
Laparoscopic surgery is suitable for both local excision and radical treatment of early gastric cancer and radical treatment of progressive gastric cancer. We should adhere to the principle of radical treatment of gastric cancer first and minimally invasive requirement second. One of the important principles of laparoscopic gastric surgery to prevent tumor-derived dissemination is to prevent tumor implantation in the perforation hole of the abdominal wall trocar. The possible mechanisms of tumor implantation in the perforation hole of the abdominal wall are mainly.
(1) Direct contamination of the gastric cancer specimen.
(2) Aerosolization of cancer cells.
(3) contamination of surgical instruments with cancer cells and then contamination of the puncture hole.
(4) leakage of CO2 gas and negative effects on cellular immunity.
In response to these possible mechanisms, principles to prevent medical dissemination of tumors include.
(1) placement of an incisional protective sleeve at the time of specimen retrieval.
(2) Heating and wetting of CO2 to reduce the aerosolization of cancer cells.
(3) Avoiding contact of surgical instruments with the tumor.
(4) fixation of the cannula and reduction of CO2 gas leakage
(5) distilled water and 52FU soaking of the abdominal wall incision.
(6) performing pneumoperitoneum-free laparoscopic gastric surgery.