Gastric cancer is a common malignant tumor worldwide, ranking fourth in incidence and second in mortality among malignant tumors. 2009 data cited by the Clinical Oncology Collaborative Center of the Chinese Anti-Cancer Association showed that “42% of the new cases of gastric cancer in the world come from China every year, amounting to nearly 400,000 people, and on average, one Chinese person dies of gastric cancer in 2-3 minutes. “On average, one Chinese person dies of stomach cancer in about 2-3 minutes. Most of the patients with early gastric cancer have almost no specific clinical manifestations, and they are often in the progressive stage when they seek medical attention. The length of survival of gastric cancer patients is closely related to their stage, and the efficacy of advanced gastric cancer is extremely poor, with a 5-year survival rate of less than 20%, much lower than that of early gastric cancer (5-year survival rate of about 90%).
The treatment of gastric cancer should adopt a comprehensive treatment method based on surgery. For patients who are in good general condition, can tolerate surgery and have no distant metastasis, radical resection should be pursued. The principles of radical surgery for gastric cancer include adequate removal of the primary focus, complete removal of perigastric lymph nodes and complete elimination of free cancer cells in the abdominal cavity. Although the extent of lymph node removal is controversial in the East and West, more and more studies have shown that D2 radical surgery can significantly improve the long-term survival rate of progressive gastric cancer.
At present, conventional radical surgery for gastric cancer has been standardized in terms of surgical indications, surgical approach and lymph node clearance. Experienced surgeons follow the principles of “gentle surgery”: gentle manipulation of tissues, proper hemostasis, sharp anatomical separation, clear and clean surgical field, avoidance of large ligatures, and use of good suture materials.
Although open surgery can effectively treat gastric cancer, it can cause new trauma to patients. The goal of achieving the best surgical treatment with minimal invasion is the goal and the principle followed by surgeons. As early as the 4th century B.C., the ancient Greek philosopher Hippocrates proposed the principle of no harm: “Medical interventions must first be as non-invasive as possible, otherwise the treatment may be worse than the natural course of the disease”.
With the development and integration of many disciplines such as clinical medicine, material science and medical engineering, surgical treatment modalities continue to evolve toward minimally invasive, miniaturized and intelligent. Minimally invasive surgery, also known as micro-invasive surgery or keyhole surgery, has become a profound technological revolution in the development of surgery. The core of minimally invasive surgery is “human-centered”, not only small incisions, but also small psychological damage, rapid recovery and the best medical performance.
In recent years, the emergence of new equipment, instruments, materials and technologies has had a great impact on the treatment of gastric cancer, not only expanding the indications for surgery, but also giving rise to some new surgical procedures. The emergence of new procedures can help reduce postoperative complications and improve treatment results.
I. New procedures with the help of endoscopic technology
In 1963, Japan began to produce fiberoptic endoscopes; in 1968, Kussmaul in Germany piloted the first rigid metal tube endoscope; and in 1987, Phillipe Mouret pioneered television endoscopic surgery. With the gradual maturation of endoscopic techniques, minimally invasive surgery was formed and developed.
Endoscopic resection of early gastric cancer is a newly emerged minimally invasive treatment method, and the main procedures include endoscopic mucosal resection (EMR) and endo-scopic submucosal dissection (ESD). For carcinoma in situ, mucosal or submucosal layer of the stomach with a diameter of <2 cm, without muscle infiltration or distant lymph node metastasis, the lesion can be resected endoscopically. Because most of the early remnant gastric cancers have already infiltrated the mucosal layer, ESD has a broader scope than EMR.
Since ESD was introduced into China in 2007, it has been rapidly promoted because of its low surgical trauma and rapid postoperative recovery.
(1) Non-ulcerated intramucosal carcinoma: well differentiated tissues, regardless of tumor size.
(2) Ulcerated intramucosal carcinoma: well differentiated and tumor diameter <3 cm.
In terms of surgical approach, ESD and EMR are local excision and cannot deal with lymph nodes, while the depth of submucosal infiltration is one of the important factors causing lymph node metastasis. If the tumor infiltrates the submucosa, the lymph node metastasis rate can be as high as 20%. The use of endoscopic resection in cases with high risk of metastasis will result in delayed treatment, thus proper preoperative evaluation of early gastric cancer is an important part of clinical decision making. Ultrasound endoscopy should be used prior to endoscopic resection to determine the depth of infiltration, the extent of the lesion, and the presence of suspicious metastases in the lymph nodes. The near-term results of endoscopic resection of early gastric cancer are moderate, but the long-term efficacy awaits further clinical studies.
New procedures with the help of laparoscopic technology
In 1987, Semm in Germany performed the first successful laparoscopic cholecystectomy on a human. In China, laparoscopic techniques started in the early 1990s, and the first laparoscopic cholecystectomy in mainland China was performed in February 1991 at the Second Hospital in Qujing, Yunnan Province. With the development of China’s economy and the advancement of related technology, laparoscopic gastric cancer surgery has been widely promoted in various places.
At present, most provincial and municipal tertiary hospitals can perform laparoscopic radical gastric cancer surgery. Laparoscopic gastric cancer surgery includes
(1) completely laparoscopic gastric cancer surgery. (1) Completely laparoscopic gastric cancer surgery, in which both gastric resection and anastomosis are done under laparoscopy, which has higher technical requirements, relatively longer operation time, more instruments required and higher cost.
(2) Laparoscopic-assisted gastric cancer surgery. Gastric freeing and lymph node dissection are done under laparoscopy, and gastric resection or anastomosis is done through small incisions in the abdominal wall, which is the most used surgical method at present.
(3) Hand-assisted laparoscopic gastric cancer surgery. During the surgical operation, the hand is inserted into the abdominal cavity through a small incision in the abdominal wall to assist in the operation.
For gastric cancer surgery, people are most concerned about safety and curative effect first, and minimally invasive effect second. Laparoscopic gastric cancer surgery should follow the radical principles and scope of open surgery in order to ensure the ideal long-term survival effect. Laparoscopy has a magnifying effect and can reveal more delicate structures such as small vasculature, nerves and fascia, so lymph node dissection under laparoscopy is more delicate than open surgery.
Compared with open surgery, the advantages of laparoscopic radical gastric cancer surgery are mainly reflected in less trauma, less disturbance of organ function, less pain and faster recovery of patients. As with conventional surgery, the final results obtained with laparoscopic radical gastric cancer treatment may be mainly related to the expertise rather than the method itself. In theory, laparoscopic completion of D2 radical surgery is completely feasible and does not differ from open surgery and should not affect the long-term survival rate of patients, but the long-term results of laparoscopic gastric cancer surgery have yet to be objectively evaluated by the results of a multicenter prospective randomized controlled study.
Several hospitals in China have established laparoscopic surgery centers, which are responsible not only for medical treatment of laparoscopic surgery but also for training of laparoscopic surgeons. The training should start from simple to difficult, and progress from theory to practice, focusing on the cultivation of minimally invasive concepts and the mastery of basic skills. With the accumulation of surgical cases and the improvement of surgeons’ skills, the surgeons’ ability to operate laparoscopically with the help of multiple devices and instruments is increasing, which will certainly increase the safety of surgery, improve the speed of surgery, and broaden the scope of surgery.
One of the major operational challenges encountered in laparoscopic surgery is suturing and ligation. A variety of anastomoses, cutters, and ligatures have been produced at home and abroad to address this problem to varying degrees. Many complications of laparoscopic surgery occur in relation to differences in their vision. Most laparoscopes currently in use are two-dimensional, with no anterior-posterior stereoscopy, resulting in slow learning adaptation by the operator and easy damage to the posterior structures. As technology advances, three-dimensional laparoscopy will benefit the majority of patients in a more convenient and affordable way. The development of new material technologies and mechanical manufacturing techniques is not only beneficial to expand the scope of laparoscopic surgery, but also key to reducing costs.
New procedures with the help of robots
In 1999, the DA-Vinci, manufactured by Intuitive Surgical, and the Zeus robotic surgical system, manufactured by Computer Motion, each received European CE market approval, marking the birth of the surgical robot. Both systems include high-quality image transfer monitors, computer-assisted surgical instruments controlled by the surgeon’s hand, a network that translates and transmits the surgeon’s hand movements, and a movable support that moves the system’s robotic arm.
In recent years, the DA-Vinci surgical system has been introduced to several hospitals in China. In robotic gastric cancer surgery, the surgeon sits on a console a few meters away from the patient, observes a high-definition three-dimensional image of the surgical field in real time through a visual display system, and uses the operating handle to control the three robotic arms that perform the surgical operation and control the field of view respectively to complete the surgery.
The DA-Vinci surgical system uses a 7-degree-of-freedom internal wrist-articulated surgical instrument that transmits to the end of the surgical instrument the precise and consistent movements that surgeons are accustomed to in traditional surgery, thus efficiently restoring the surgeon’s natural, dexterous surgical ability and overcoming the surgeon’s fatigue-related tremors and imprecision, as well as the mirror image effect of traditional laparoscopic movements. effects of traditional laparoscopic surgery.
Robotic gastric cancer surgery is a revolution in the field of surgery with clear advantages: precise positioning, multi-degree of freedom of movement, no visual blind spots, and filtering of the surgeon’s hand tremors. The main disadvantages are: the lack of feedback of sensory information, the need for a trained mechanic to cooperate with the surgery, and the relatively high wear and tear of the instruments. The current surgical robotic system is expensive, limited hospitals have the equipment, few surgeons have been specially trained, few clinical cases have been accumulated, and even fewer prospective collaborative studies have been conducted. Radical surgery for gastric cancer can be performed by surgical robots, but its practical value and safety have yet to be confirmed by prospective randomized studies.
In 2001, surgeons in New York, USA, performed a gallbladder resection on a patient remotely via a high-speed fiber-optic cable across the Atlantic Ocean using a robotic hand manipulating a television screen in the operating room of a hospital in Strasbourg, France, and successfully completed the operation in less than an hour. In the near future, robotic remote radical gastric cancer surgery may be promoted worldwide.
IV. Outlook
Minimally invasive or non-invasive is an important goal for surgeons. As a hot topic in the 21st century, minimally invasive surgery is a product of combining traditional theories of surgery with modern science and technology, which mainly depends on the comprehensive development of electronic information technology, bioengineering technology and mechanical engineering technology. In essence, minimally invasive surgery is the supplement and development of traditional surgery. New surgical procedures based on minimally invasive surgery must be based on the premise of efficacy, and their efficacy must be similar to, equal to or better than traditional surgery, which is the key to the problem. Objective evaluation of the efficacy of these new procedures usually takes 5-10 years. In the author’s opinion, to improve and promote these new procedures, we may do some work from the following aspects.
1) Establish and promote the standardized training and qualification system for new procedures: The standardization of new procedures depends on the establishment of training, qualification and quality control system for new procedures. At the same time, the improvement of relevant laws and regulations should be accelerated to regulate the behavior and responsibilities of doctors, so as to promote the professionalization and professionalization of surgeons.
2. Pay attention to basic research related to new surgical procedures: we should start from pathophysiological research and focus on exploring whether these new procedures can bring less traumatic reactions, inflammatory reactions, internal environmental disorders and immune function effects to patients.
3. Pay attention to the clinical research related to the new procedures: not only the scientific evaluation of the recent efficacy, such as intraoperative bleeding, operation time, complication rate, etc., but also the evaluation of the long-term efficacy, such as quality of life index, 5-year survival rate and other efficacy indicators through multicenter prospective randomized controlled studies.