Analysis of multiple factors influencing the survival of patients with advanced gastric cancer

Follow-up

The follow-up of 120 patients was conducted over a period of 60 months through telephone, text message or outpatient visits. The observation time started at discharge after the hospital operation and ended at 5 years. The outcomes included survival, death and loss to follow-up. Overall survival (OS) was defined as the time span between surgery and death.

Statistical methods

The statistical analysis was conducted using SPSS 19.0 software. The categorical data are presented as percentages, and the description of continuous data can be achieved by calculating standard deviations or employing medians. Chi-square test or rank sum test was used for univariate analysis, followed by Kaplan-Meier survival analysis to calculate the median survival time and 5-year cumulative survival. The association between variables and survival was assessed and explained using univariate and multivariate Cox proportional hazards regression models. The test level was α = 0.05.

Availability of data and materials

The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request.

Analysis of patient survival

The results of K-M analysis revealed a negative correlation between the 5-year survival rate of patients and tumor location, differentiation degree, depth of invasion, regional lymph node metastasis, and postoperative tumor stage. (P < 0.05), while age, sex, CEA level, tumor size, lymphatic tumor thrombolus, and nerve invasion were not correlated with prognosis (P > 0.05). (Table 2).

Analysis of factors affecting survival

After adjusting for and controlling for confounding variables, we screened out the independent predictors that significantly influence 5-year survival after radical surgery, including the degree of histological differentiation (HR = 1.441; 95% CI = 1.049–1.979, P = 0.024) (Figure 2), regional lymph node (HR = 1.626; 95% CI = 1.160–2.279, P = 0.005) (Figure 3), and pTNM stage (HR = 2.266; 95% CI =1.335–3.847, P = 0.002) (Figure 4), which were found to be independent risk factors for poor survival (Table 3). Tumor location (P = 0.191), invasion depth (P = 0.579) and tumor size (P = 0.324) were not found to be independent risk factors.

Figure 2. Survival curve of tumor differentiation on overall survival, P = 0.024.

Figure 3. Survival curve of lymphatic and metastatic effects on overall survival, P = 0.005.

Figure 4. Graph of the effect of postoperative pathological staging on overall survival, P = 0.002.

Analysis of the scope of lymph node dissection for advanced gastric cancer

The performance of lymph node dissection during surgical resection of gastric cancer not only plays a crucial role in staging, but also significantly impacts patient prognosis. Lymph node dissection during surgical resection of gastric cancer plays an important role not only in staging but also in patient prognosis. At present, the standard radical surgery for gastric cancer is D2 gastrectomy, which can be treated by open or endoscopic treatment. However, the development of this technique is limited to our hospital, and all patients in this group were treated by open D2 radical surgery. The purpose of lymph node dissection is to assess the extent of lymph node metastasis and enhance surgical outcomes. However, for patients with an advanced gastric cancer, the benefit of lymphadenectomy, in addition to D2 gastrectomy, remains controversial. According to the latest guidelines, if the tumor infiltrates the duodenum, it is recommended to perform resection of lymph nodes located posteriorly to the pancreatic head (Group 13), defined as D2+13. If Group 6 of the lymph nodes were found to have metastasis, 14v was removed; this group was called D2+14v. Therefore, in the tumor surgical guidelines of the Society of Oncology of Japan, Korea, and Europe, D2 lymphadenectomy is strongly recommended as the standard procedure for treating advanced gastric cancer. The National Comprehensive Cancer Center (NCCN) also recommended D1 or modified D2 lymph node dissection for advanced gastric cancer [6]. Advanced proximal gastric cancer may metastasize to the lymph nodes located at the splenic hilum, specifically No. 10 LN. Total gastrectomy combined with splenectomy is a method for complete resection of 10 groups of lymph nodes. However, splenectomy has many disadvantages for patients. A randomized controlled trial in Japan (JCOG0110) clearly showed that preventive splenectomy is not necessary unless the tumor has invaded the greater curvature [7]. Laparoscopic/robotic splenohilal resection with enhanced visualization has been developed that promises to replace preventive splenectomy with equal tumor outcomes and lower morbidity. The extensive dissection of lymph nodes directly impacts patient prognosis and increases the likelihood of postoperative complications, while also ensuring sufficient lymph node counts and a high rate of lymph node metastasis [8, 9]. For this reason, an appropriate scope of lymph node dissection can improve patient survival [10]. Lymphatic tracers can better guide lymph node dissection, and indocyanine green can significantly increase the number of D2 lymph node dissections without increasing complications. Indocyanine green fluorescence imaging can be used for routine lymphatic localization in laparoscopic gastrectomy, especially total gastrectomy [11]. Regional lymph node metastasis was an independent risk factor for survival in this cohort. Of course, lymph node metastasis, a factor affecting patient survival, is important [12]. As reported in the literature [13], there is a significant difference in survival even for patients with negative lymph nodes, indicating that the impact of other risk factors on survival cannot be ignored.

Analysis of factors affecting the survival of gastric cancer patients

According to factor analysis, tumor location, size, and depth of invasion are not independent risk factors for prognosis, and more regional lymph node metastases are involved [14]. Although tumor location and invasion depth cannot be independent risk factors, they both affect the path of tumor metastasis to the lymph node and are potential correlation factors. During tumor progression, cancer cells migrate to regional lymph nodes under the action of chemokines. A positive regional lymph node affects the prognosis of patients; even if radical surgery is performed for early gastric cancer. In the process of tumor proliferation and invasion, cancer cells are influenced by chemokines to migrate towards regional lymph nodes. The presence of positive regional lymph nodes significantly impacts the prognosis of patients, even after undergoing radical surgery for early gastric cancer, if the lymph nodes are positive, the prognosis is relatively poor. As the number of lymph node metastases increased, the degree of invasion increased, the tumor heterogeneity increased, and the tumor evolution and survival rate decreased significantly. Kim et al. [15] analyzed 10050 patients with gastric cancer; N2-3 patients accounted for 29.2%, and the 5-year OS rates of N0, the N1, N2 and N3 patients were 93.3%, 78.1%, 64.3% and 33.7%, respectively. Lymph nodes should be dissected, with no less than 10 nodes in the T1 stage and no less than 16 nodes in other T stages, to better determine the status of lymph node metastasis and its impact on long-term survival [16–18]. In this study, the regional lymph node status was found to be an independent risk factor for gastric adenocarcinoma survival. Compared with the 6th edition, the 7th edition of the TNM classification system is more reliable and accurate at classifying the number of metastatic lymph nodes to predict OS after radical gastrectomy [19]. The degree of tumor differentiation is an observation index for endoscopic treatment of early cancer, and the frequency of lymph node metastasis and submucosal invasion of poorly differentiated adenocarcinoma is high [20]. In this cohort, the 5-year survival rate of poorly differentiated patients was 34.8%. A poorly differentiated tumor and an increased probability of regional lymph node metastasis were found to be independent prognostic risk factors. The stage of cancer is the most important independent prognostic factor [21–24]. The Cox model was used in some studies to show that the risk of death in stage III patients is 2.82 times that in stage II patients, and that in stage IV patients is 3.29 times that in stage II patients [21]. The presence of PTNM serves as a significant independent prognostic indicator for patients with gastric cancer patients [25, 26] and can forecast patients’ prognosis and offer treatment recommendations. The prognosis of patients varied significantly across different disease stages. [27]. The relationship between the prognosis of 10,050 patients with stomach cancer and various stages was analyzed by Kim et al. [15]. According to the AJCC staging system of the 7th edition [28], stage III patients accounted for 25% of the patients. The 5-year OS rates of patients with stage Ia, Ib, IIa, IIb, IIIa, IIIb, IIIc and IV disease were 96.1%, 93.5%, 84.9%, 76.1%, 66.7%, 43.8%, 24.9% and 10.1%, respectively. According to our clinical data analysis, pTNM stage had been confirmed as an independent risk factor in gastric cancer, and with the advanced stage, the clinical prognosis was correspondingly poor. In this cohort, the 5-year survival of stage Ib patients was significantly greater than that of stage II and III patients. Therefore, studying how to detect gastric cancer early is highly important for its prevention and treatment.

The present study is a retrospective analysis conducted at a single research center, which lacks data analysis of multi-center bulk medical records, and has certain research defects, which may affect the results of multi-factor analysis. More clinical data will be included in later studies.

In conclusion, the differentiation of tumors, the metastasis to regional lymph nodes and postoperative pathological stage were found to be independent risk factors for 5-year overall survival in patients with advanced gastric cancer. Standard and reasonable lymph node dissection and accurate postoperative pathological staging provide important support for the prognosis of advanced gastric cancer patients.