The impact of adjuvant oxaliplatin and tumor sidedness on the overall survival of stage IIB colon cancer patients: a multicentre study.

The aim of this multicentre retrospective study was to compare the efficacy of adjuvant chemotherapy regimens both with and without oxaliplatin and tumor sidedness in stage IIB (pT4aN0) colon cancer patients. This study included patients with stage IIB colon cancer who underwent curative surgery and received adjuvant chemotherapy. The patients were divided into two groups (one with and one without oxaliplatin) to compare the overall survival (OS) in right- and left-sided tumors. The study population included 298 patients with stage IIB colon cancer (median age: 57) of whom 69.1% were male. Forty-four per cent of these patients (n = 131) were diagnosed with right-sided colon cancer. The median follow-up duration was 35.9 months. In the entire population, a median OS was not reached, and the five-year OS was 83%. The median disease-free survival (DFS) was 12 months. There was no significant difference in terms of the five-year OS between right- (82%) and left-sided (84%) colon tumors (p = 0.67). In addition, the five-year OS of patients treated with and without oxaliplatin were 76% and 89%, respectively, and there was no statistically significant difference (p = 0.23). The five-year OS of the patients treated with and without oxaliplatin were 83% and 96.5%, respectively, (p = 0.8) in right-sided colon tumors, while it was 75% and 93% (p = 0.06), respectively, in left-sided colon tumors. Tumor sidedness and the addition of oxaliplatin to adjuvant chemotherapy were not found to be associated with the OS in stage IIB colon cancer patients in our study. Further large prospective studies that also include MSI, RAS and BRAF status data are warranted in colon cancer patients.

Water quality assessment of the Karasu River (Turkey) using various indices, multivariate statistics and APCS-MLR model.

Determining the water quality status of a river and accurately identifying potential pollution sources threatening the river are pillars in effective control of pollution and sustainable water management. In this study, water quality indices, multivariate statistics and absolute principal component score-multiple linear regression (APCS-MLR) were applied to evaluate the water quality of the Karasu River, the main tributary of the Euphrates River (Turkey). For this, 19 water quality variables were monitored monthly at eight stations along the river during one year. Based on the mean dissolved oxygen (DO), electrical conductivity (EC), nitrate-nitrogen (NO3-N), orthophosphate-phosphorus (PO4-P), total phosphorus (TP), ammonium-nitrogen (NH4-N), chemical oxygen demand (COD) and total nitrogen (TN) levels, most stations of the river had "very good" water status according to surface water quality criteria. Spatial cluster analysis (CA) divided eight stations into three regions as clean region, moderate clean region and very clean region. The mean values of Nutrient Pollution Index indicated that the river was "no polluted". Similarly, Water Quality Index and Organic Pollution Index values indicated that the river water quality was between "good" and "excellent". A minimum water quality index (WQImin) consisted of ten crucial parameters was not significantly different with the WQI based on all the 17 parameters. Discriminant analysis (DA) results showed that water temperature (WT), EC, chlorophyll-a (Chl-a), potassium (K), calcium (Ca), NO3-N and COD are the variables responsible for temporal changes, while WT, total dissolves solids (TDS), Chl-a, K, magnesium (Mg), Ca, NH4-N and COD are the variables responsible for spatial changes in the river water quality. Principal component analysis/factor analysis (PCA/FA) identified four potential sources, including anthropogenic, natural, seasonal and phytoplankton. Source apportionment in the APCS-MLR model revealed that seasonal and anthropogenic sources contributed 35.2% and 25.5% to river water quality parameters, respectively, followed by phytoplankton (21.4%) and natural sources (17.9%).

Spatiotemporal variations, health risks, pollution status and possible sources of dissolved trace metal(loid)s in the Karasu River, Turkey.

The Karasu River is the main tributary of the Euphrates River, which is the longest river in Southwest Asia. Domestic and industrial wastewater discharges, agricultural practices and mining activities in the basin can cause potential toxic metal pollution in the Karasu River. However, very little is known about the levels of dissolved trace metal(loid)s (TMs) in the river. In this study, levels of ten TMs (Fe, Al, Cd, Ni, Cu, Zn, Pb, As, Mn and Cr) in water samples taken monthly from 8 stations along the Karasu River between January 2019 and December 2019 were measured and compared with water quality guidelines. In addition, spatial and seasonal variations, health risks, pollution status and possible sources of the TMs were assessed. The 90th percentile levels of the TMs were below the drinking water standards. The highest total concentration was recorded at the most upstream station due to weathering processes, and rain and snowmelt runoff. The total metal concentration showed an increasing trend from winter to summer due to the combined effect of natural and anthropogenic sources. Metal pollution indices indicated that river water quality is suitable for potable uses. The results of factor and cluster analyses revealed that Ni, Fe, Mn and Cr are controlled by both lithogenic sources and anthropogenic activities, while other TMs are controlled by lithogenic sources. The hazard quotient (HQ) of each TM for both water ingestion and dermal contact pathways for residents was below the risk level. However, the hazard index (sum of HQs of all TMs) for water ingestion for children was higher than the risk level, indicated that the ingestion of ten TMs in the Karasu River may pose non-carcinogenic health risks to children. The carcinogenic risk results of As and Cr for both water ingestion and dermal absorption were within or below the acceptable carcinogenic risk range.