Epidemiological and clinical description of patients with oropharyngeal cancer treated in a public oncology referral hospital in Chile.

Introduction: The incidence of squamous carcinoma of the oropharynx (OPSCC) has presented an increase worldwide, a fact that occurs along with a phenomenon of epidemiological transition, whose pathogenesis is linked to human papilloma virus (HPV) in a significant part of the cases. Published evidence at the Latin American level is scarce. The present study aims to evaluate the epidemiological and clinical characteristics of patients with oropharyngeal cancer treated in a public oncology reference centre in Chile. Methodology: A cross-sectional study was carried out. Patients with histological confirmation of OPSCC aged 18 years or older, referred to the National Cancer Institute of Chile between 2012 and 2023 were included. The association with HPV was determined by immunohistochemistry for p16. Results: 178 patients were analysed, most of them in locoregionally advanced stages involving the palatine tonsil. Seventy-seven percent were male, with a median age of 60 years. Sixty-seven percent of patients were positive for p16, with a progressive increase to 85% in the last 2 years of the study. The p16(+) patients were younger and had fewer classical risk factors. Primary treatment was radiotherapy in 94% of patients. Conclusion: The epidemiological profile of patients with OPSCC treated in a Chilean public oncology referral centre reflects the epidemiological transition observed in developed countries. This change justifies the need to adapt health policies and conduct research that considers the characteristics of this new epidemiological profile.

Clinical relevance of the use of Dentoxol® for oral mucositis induced by radiotherapy: A phase II clinical trial.

BACKGROUND: Severe oral mucositis associated with cancer therapy is a frequent complication that may affect a patient's systemic condition, resulting in interruption and/or prolongation of cancer therapy. Dentoxol® is a medical solution in the form of a mouthwash that has been shown to result in statistically significant improvement in the prevention of severe oral mucositis. However, knowing the measures of the clinical significance of this therapy is important for accurate decision-making. AIM: To describe the clinical impact of Dentoxol® use in severe oral mucositis. METHODS: Clinical significance was measured using the results obtained in a randomized controlled clinical trial previously conducted by the same group of researchers. The measures of clinical significance evaluated were the absolute risk or incidence, relative risk, absolute risk reduction, relative risk reduction, number needed to treat, and odds ratio. RESULTS: The data obtained show that the impact of Dentoxol® on reducing the severity of oral mucositis has important clinical relevance. CONCLUSION: The results of this study justify the incorporation of Dentoxol® mouth rinse into clinical protocols as a complement to cancer therapy to prevent and/or treat oral mucositis secondary to radiotherapy.

Efficacy and safety of Dentoxol® in the prevention of radiation-induced oral mucositis in head and neck cancer patients (ESDOM): a randomized, multicenter, double-blind, placebo-controlled, phase II trial.

PURPOSE: The aim of this study was to assess the efficacy and safety of Dentoxol mouthrinse in reducing the severity of oral mucositis (OM) secondary to radiation therapy (RT) for head and neck cancer. METHODS: A randomized, double-blind, placebo-controlled, multicenter phase II clinical trial was conducted. Subjects were asked to use Dentoxol (n = 55) or control (n = 53) mouthrinse 5 times/day during RT. Twice a week, OM was assessed clinically using the WHO scale and the Oral Mucositis Daily Questionnaire (OMDQ) was completed. RESULTS: The incidence of severe OM was 40.7% in the Dentoxol group and 51% in the control group (p = 0.265). Comparing all recorded clinical assessments, severe OM was seen in 13.3% of all assessments in the Dentoxol group vs. 21.8% in the control group (p = 0.000). There was a statistically significant lower proportion of assessments showing severe OM in the Dentoxol group at weeks 4, 5, and 6 of RT. The mean duration of severe OM was 11.95 days in the Dentoxol group vs. 14.59 days in the control group (p = 0.502). There was no difference between groups in mouth pain and its impact on function. The use of Dentoxol was safe and was not linked to any serious adverse events. CONCLUSION: The use of Dentoxol 5 times/day is safe and resulted in significantly fewer time-points with severe OM and a delay in the onset of severe OM, compared with a control rinse. A phase III clinical trial is warranted to confirm efficacy and address the limitations of this study.

A compilation of field surveys on gaseous elemental mercury (GEM) from contrasting environmental settings in Europe, South America, South Africa and China: separating fads from facts.

Mercury is transported globally in the atmosphere mostly in gaseous elemental form (GEM, [Formula: see text]), but still few worldwide studies taking into account different and contrasted environmental settings are available in a single publication. This work presents and discusses data from Argentina, Bolivia, Bosnia and Herzegovina, Brazil, Chile, China, Croatia, Finland, Italy, Russia, South Africa, Spain, Slovenia and Venezuela. We classified the information in four groups: (1) mining districts where this contaminant poses or has posed a risk for human populations and/or ecosystems; (2) cities, where the concentration of atmospheric mercury could be higher than normal due to the burning of fossil fuels and industrial activities; (3) areas with natural emissions from volcanoes; and (4) pristine areas where no anthropogenic influence was apparent. All the surveys were performed using portable LUMEX RA-915 series atomic absorption spectrometers. The results for cities fall within a low GEM concentration range that rarely exceeds 30 ng m(-3), that is, 6.6 times lower than the restrictive ATSDR threshold (200 ng m(-3)) for chronic exposure to this pollutant. We also observed this behavior in the former mercury mining districts, where few data were above 200 ng m(-3). We noted that high concentrations of GEM are localized phenomena that fade away in short distances. However, this does not imply that they do not pose a risk for those working in close proximity to the source. This is the case of the artisanal gold miners that heat the Au-Hg amalgam to vaporize mercury. In this respect, while GEM can be truly regarded as a hazard, because of possible physical-chemical transformations into other species, it is only under these localized conditions, implying exposure to high GEM concentrations, which it becomes a direct risk for humans.

Application of water quality indices and analysis of the surface water quality monitoring network in semiarid North-Central Chile.

Surface water quality has increasing importance worldwide and is particularly relevant in the semiarid North-Central Chile, where agriculture and mining activities are imposing heavy pressure on limited water resources. The current study presents the application of a water quality index in four watersheds of the 29°-33°S realm for the period 1999-2008, based on the Canadian Council of Ministers for the Environment approach and the Chilean regulation for irrigation water quality. In addition, two modifications to the index are tested and a comprehensive characterization of the existing monitoring network is performed through cluster analysis. The basins studied show fairly good water quality in the overall, specially the Limarí basin. On the other hand, the lower index values were obtained for the headwaters of Elqui, associated with the El Indio mining district. The first modification of the indicator (i.e., to consider parameters differentially according to their effect on human health or the environment) did not produce major differences with respect to the original index, given the generally good water quality. The second modification (i.e., to consider as threshold values the more restrictive figures derived from a set of regulations) yielded important differences in the indicator values. Finally, an adequate characterization of the monitoring network was obtained. The results presented spatial coherence and the information can be used as a basis for the optimization of the monitoring network if required.

Stakeholder participation within the public environmental system in Chile: major gaps between theory and practice.

The main objective of this paper is to present a critical analysis of the stakeholder participation process within the Environmental Impact Assessment System in Chile, after ca. 14 years of being enforced. This analysis is sustained by the description and analysis of the stakeholder participation possibilities in a representative rural area of North-Central Chile. The Environmental Basis Act 19300, enacted in 1994, considers the participation of the local community in the environmental impact assessment of new projects. However, this possibility is very limited and difficult to exert, often resulting in frustration for the participants. This is due to a number of reasons, such as the imbalance of resources and knowledge among the majority of participating communities and project proponents, the complexity and administrative and legal constraints to participation, and the dominant interest of the Central Government in approving investments, specifically in energy and natural resources related projects, which generate wealth and jobs. Also, the State's rush to develop Internet-based communication and management systems has built a barrier for poor, traditional communities. This factor is clearly reflected in the case study considered. Results show that there is generally a significant lack of knowledge about institutions and participation tools. From this base, we intend to raise concern on these selected aspects that could be addressed to improve the effectiveness of the existing framework, both in Chile and in other developing countries, where immature environmental impact assessment and public management systems face similar pressures in relation to the sustainable use of their natural resources. Finally, some basic steps are proposed in order to make the community participation an effective tool for sustainable development.

Natural factors and mining activity bearings on the water quality of the Choapa basin, North Central Chile: insights on the role of mafic volcanic rocks in the buffering of the acid drainage process.

This contribution analyzes water chemical data for the Choapa basin, North Central Chile, for the period 1980-2004. The parameters considered are As, Cu Fe, pH, EC, SO4⁻², Cl⁻¹, and HCO[Formula: see text], from samples taken in nine monitoring stations throughout the basin. Results show rather moderate contents of As, Cu, and Fe, with the exception of the Cuncumén River and the Aucó creek, explained by the influence of the huge porphyry copper deposit of Los Pelambres and by the presence of mining operations, respectively. When compared against results obtained in previous researches at the neighboring Elqui river basin, which host the El Indio Au-Cu-As district, a much reduced grade of pollution is recognized for the Choapa basin. Considering the effect of acid rock drainage (ARD)-related Cu contents on the fine fraction of the sediments of both river basins, the differences recorded are even more striking. Although the Los Pelambres porphyry copper deposit, on the headwaters of the Choapa river basin, is between one and two orders of magnitude bigger than El Indio, stream water and sediments of the former exhibit significantly lower copper contents than those of the latter. A main factor which may explain these results is the smaller degree of H( + )-metasomatism on the host rocks of the Los Pelambres deposit, where mafic andesitic volcanic rocks presenting propylitic hydrothermal alteration are dominant. This fact contrast with the highly altered host rocks of El Indio district, where most of them have lost their potential to neutralize ARD.

Contributions of the different water sources to the Elqui river runoff (northern Chile) evaluated by H/O isotopes.

We present the results of an isotope (2H and 18O) and hydrogeochemical study in order to constrain the origin, recharge, and evolution of the surface and groundwater in the arid Andean realm of the Elqui watershed. The results of 2H and18O analyses of water samples obtained during our summer and winter campaigns indicate a generally meteoric origin of the river and spring waters of the watershed. The isotope signature of water of the Elqui river and its tributaries as well as that of groundwater in the coastal region fits the 2H-18O relation of delta2H =7.61delta18O+6.1. A relatively fast discharge and a quasi-closed catchment area can be asserted for water along the river flow path. The tributaries from the more arid coastal area, north of the Elqui river, differ in their isotopic signature due to evaporation and hydrochemically due to interactions with the strongly altered and fractured volcanic rocks of the basement. In the Andean zone, the18O-enriched hydrothermal spring of Baños del Toro exhibits the influence of water-rock interaction processes. The chemistry of the river water changes from sulphate- to chloride-rich along the river course from the high Andean mountains to the coast. The sulphate-rich character of these Andean waters reflects their passage through sulphide-rich rock massifs that were subjected to strong oxidation processes in the near superficial environment. This sulphate signature is enforced by past and present mining of precious metal epithermal deposits (e.g. those of El Indio-Tambo Au-Cu-As district), in which mineralised zones were developed during a series of Miocene magmatic-hydrothermal episodes in the Andean realm. Owing to the proximity of the lower Elqui river waters and its tributaries to the Pacific coast, the chloride character may be induced by agricultural and marine (sea spray, fog) sources. Generally, the main source of the Elqui river water is mainly attributed to surface runoff and less to contributions from the basement fractured aquifer.