Characteristics of lymph node metastasis and evaluating the efficacy of endoscopic submucosal dissection in early gastric cancer / 北京大学学报(医学版)

OBJECTIVE@#To investigate the correlation between clinicopathological features and lymph node metastasis, and to evaluate the feasibility and efficacy of endoscopic submucosal dissection (ESD) in early gastric cancer (EGC) by comparing with surgery treatment.@*METHODS@#The clinicopathological data of 320 patients with EGC who were treated in Peking University First Hospital between January 2010 and December 2017 were retrospectively reviewed, in which there were 198 cases of surgical procedure and 122 cases of ESD. Characteristics of lymph node metastasis in EGC were analyzed, and lymph node metastasis of EGC with ESD absolute and expanded indications were summarized. The long-term efficacy of ESD and surgical treatment of EGC were compared to evaluate the rationality of absolute and expanded indications of ESD.@*RESULTS@#Lymph node metastasis was detected in 22 (11.1%) of 198 patients. Univariate analysis showed a positive relationship between tumor size (χ2=5.525, P=0.019), depth of invasion(χ2=8.235, P=0.004), histological type (χ2=6.323, P=0.012), lymphovascular invasion (χ2=12.273, P < 0.001) and lymph node metastasis in EGC. Multivariate analysis revealed that depth of invasion(Wald=7.575, P=0.006) and histological type (Wald=6.317, P=0.012) were independent relative factors of lymph node metastasis in EGC. The lymph node metastasis rates of the patients with absolute and expanded ESD indications were both 0%. The 5-year survival rates of the patients who met ESD absolute indication receiving surgery treatment and ESD were 97.6% and 97.9% respectively, and the difference between the two groups was not statistically significant(χ2=0.014, P=0.907).The 5-year survival rates of the patients who met ESD expanded indication receiving surgery treatment and ESD were 96.5% and 91.7% respectively, the difference between the two groups was not statistically significant(χ2=1.061, P=0.303).@*CONCLUSION@#Lymph node metastasis in EGC is mainly correlated with depth of invasion and histological type. Our data indicate that ESD procedure for EGC is comparable to surgery in terms of long-term efficacy in both absolute and expanded indications. However, some studies of a large sample size are still needed for more confirmation.

Adapting the RUSLE and GIS to model soil erosion risk in a mountains karst watershed, Guizhou Province, China.

Soil erosion is a serious environmental problem in Guizhou Province, which is located in the centre of the karst areas of southwestern China. Unfortunately, Guizhou Province suffers from a lack of financial resources to research, monitor and model soil erosion at large watershed. In order to assess the soil erosion risk, soil erosion modeling at the watershed scale are urgently needed to be undertaken. This study integrated the Revised Universal Soil Loss Equation (RUSLE) with a Geographic Information System (GIS) to estimate soil loss and identify the risk erosion areas in the Maotiao River watershed, which is a typical rural watershed in Guizhou Province. All factors used in the RUSLE were calculated for the watershed using local data. It was classified into five categories ranging from minimal risk to extreme erosion risk depending on the calculated soil erosion amount. The soil erosion map was linked to land use, elevation and slope maps to explore the relationship between soil erosion and environmental factors and identify the areas of soil erosion risk. The results can be used to advice the local government in prioritizing the areas of immediate erosion mitigation. The integrated approach allows for relatively easy, fast, and cost-effective estimation of spatially distributed soil erosion. It thus indicates that RUSLE-GIS model is a useful and efficient tool for evaluating and mapping soil erosion risk at a large watershed scale in Guizhou Province.