With adequate treatment for early gastric cancer, survival can exceed 90%. The frequency of lesions of regional lymph nodes in TI with invasion within the mucous membrane is about 4%, with invasion of the submucosal layer – 23% and correlates with factors such as the form of growth, the presence of ulceration, the size, and the degree of differentiation of the tumor. Therefore, with a highly differentiated tumor less than 3 cm in size, in the largest dimension and without signs of ulceration, its endoscopic resection is possible.
The surgical method remains the main one in the treatment of stomach cancer. According to the recommendations of ESMO (2005), surgical treatment is recommended for the following tumor prevalence according to the TNM system: Tis-T3N0-N2M0 and T4N0M0. With gastric cancer, a gastrectomy or resection of the stomach of various sizes is performed with the removal of the ligamentous apparatus and regional lymph nodes. Subtotal proximal resection of the stomach is performed with exophytic cancer of the proximal stomach, which does not extend beyond the cardia . An indication for subtotal distal gastric resection is an exophytic tumor of the distal stomach, which does not extend proximal to the angle of the stomach. With infiltrative tumors of various localization, total lesion, exophytic tumor of the body of the stomach, gastrectomy is indicated . In order to achieve the radicality of surgical intervention with type I and II according to Borrmann, it is necessary to retreat more than 3 cm from the proximal edge of the tumor, with type III and IV – 6 cm. The published data do not allow to confirm the advantage of one volume of surgical intervention over another. The volume of lymph node dissection has been the subject of controversy to this day. Lymphatic dissection D2 is the standard volume for gastric cancer surgery as recommended by the JCGC. Clinical trials conducted in Japan showed improved survival in the absence of an increase in the incidence of complications and mortality in patients undergoing gastrectomy with D2 lymphadenectomy . However, studies by MRC and the Dutch group for the study of gastric cancer, which involved 400 and 711 patients, respectively, did not reveal an increase in survival after lymph node dissection D2. In both studies, in the group of patients with extended lymphadenectomy , an increase in the frequency of postoperative complications and mortality was noted, which was most likely associated with the performance of distal pancreatic resection of the pancreas and splenectomy in these patients , procedures that are not necessary to remove the lymph nodes. In addition, the volume of lymphatic dissection did not always correspond to the volume L) l or D2, which further complicated the interpretation of the results and comparison of groups.
Chemotherapy in an independent treatment option is used in patients with disseminated gastric cancer. The main chemotherapy drugs for this disease are fluorouracil , cisplagine , mitomycin and taxanes . According to the literature, the frequency of objective effects during chemotherapy with these drugs ranges from 17 to 30%. The use of chemotherapy, according to randomized trials, can extend the life of patients with distant metastases up to 12 months.
When using combination chemotherapy, the effectiveness of treatment is higher. The most commonly used regimens are PF ( cisplatin and fluorouracil ), ELF ( fluorouracil , calcium folinate and leucovorin ), FAMTX ( fluorouracil , doxorubicin , calcium folinate and methotrexate ), PEF ( cisplatin , etoposide and fluorouracil ).
Recently, the use of taxanes , irinotecan , capecitabine has been recognized . The use of docetaxel and cisplatin was effective in 37% of patients with gastric cancer.
The need for chemotherapy at the first stage of the combined treatment of gastric cancer is confirmed by studies on autopsy material, which showed that even in the early stages, cancer of this localization often becomes systemic. Modern studies on the efficacy of laparoscopy and PET in assessing the prevalence of tumors confirm this thesis. Neoadjuvant treatment leads to a decrease in the bulk of the tumor in most patients, increased resectability , and reduces the risk of intraoperative seeding of the wound with tumor cells. In addition, a histological examination of the removed preparation makes it possible to objectively evaluate the effect of treatment performed before surgery. There are several theoretical and experimental justifications for the use of chemotherapy precisely at the preoperative stage of treatment of patients with gastric cancer. Experimental studies show that surgical intervention stimulates the growth of tumor cells remaining in the patient’s body after surgery. This is evidenced by an increase in the proliferation index, a significant decrease in cell replication time, and a rapid increase in the number and size of distant metastatic foci after surgery. An increase in the proliferation index may be accompanied by mutations leading to the formation of cell clones resistant to chemotherapy. An additional argument in favor of the use of neoadjuvant treatment (chemotherapy) at the preoperative stage is the best delivery of chemotherapeutic agents to the tumor tissue in conditions of blood flow in the tumor bed not compromised by surgical intervention.
To date, the literature has published the results of three clinical studies on the effect of neoadjuvant chemotherapy on treatment efficacy. As a result of chemotherapy before surgery, it was possible to reduce the prevalence of the tumor process, however, one of them failed to improve the survival of patients in the group with preoperative chemotherapy.
Metastatic damage to the lymph nodes is a prognostically unfavorable factor in patients who received radical surgical treatment, which gives rise to attempts to improve survival in high-risk patients through the use of adjuvant chemotherapy. A large number of clinical trials on the use of chemotherapy in the postoperative period have been published in the literature. The studies completed to date on the role of adjuvant chemotherapy after surgical treatment do not allow us to draw final conclusions about its effectiveness. Only a few of them managed to improve the treatment results in the group with combined treatment compared with patients who underwent only surgical treatment. At the same time, a meta-analysis of all clinical studies shows a slight, but obvious improvement in survival in the main group of patients. To confirm these data, carefully planned clinical trials using new effective drugs are necessary. The most commonly used drugs are mitomycin , fluorouracil , anthracyclines . More often a combination of two or more drugs is used.
Adjuvant Intraperitoneal Chemotherapy
The use of this adjuvant treatment regimen is due to the rather high rate of relapse in the abdominal cavity. Clinical studies have been conducted on the use of cisplatin , mitomycin and fluorouracil for intraperitoneal adjuvant chemotherapy. However, there was no significant improvement in long-term results.
As an independent method, radiation therapy is carried out in case of locoregional relapse of gastric cancer after surgical treatment or as an additional treatment in the presence of tumor cells along the line of resection of the surgical preparation. The use of radiation therapy in adjuvant mode to date remains an experimental direction in the treatment of gastric cancer. The widespread use of radiation therapy in combination with chemotherapy in adjuvant and neoadjuvant modes. Despite preliminary favorable results, it cannot be recommended for widespread use in preoperative or postoperative treatment.
Stomach cancer prognosis
According to statistics, the most favorable prognosis is characteristic for cancer of the antrum and pyloric canal of the stomach – 5-year survival exceeds 35%. The least favorable cancer is proximal gastric cancer – survival rate of less than 20%. An intermediate position is occupied by cancer of the body of the stomach, 5-year survival with this localization ranges from 25 to 35%.