The Evaluation And Quality Control Of The High Risk Areas For Cancer In China

Background and Aims: It had been more than thirty years since the establishment of high risk areas for cancer in China. The unique characteristics of high risk areas in China were as followings; in remote rural area, stable population, less mobile and similar genetic background. Those high risk areas have the particular advantages in the studies of cancer epidemiology and prevention.The prevention of cancer among the population in the high risk areas for cancer is a long-term field work, and needs the accumulation and summarization of experience for many years. However, there is still no such systematic and scientific evaluation of the field work in the aspects of management and operation methods so far. Therefore, in the first part of the thesis, field studies in the high risk areas for cancer were synthetically evaluated. In the second part of the thesis, the improvement of quality control in a high risk area for gastric cancer was discussed based on an intervention trial of precancerous gastric lesions in Linqu County, Shandong Province.Methods: In the first part, seven representative high risk areas for cancers were selected in terms of the different cancers, geographic distribution, etc. and were evaluated in terms of general characteristics, cancer registries and scientific programs of research. The Rank Sum Ratio (RSR) test was used to evaluate the quality of scientific research and their synthetical quality in the high risk areas. The partial least square regression was used to analyze the correlation between the scientific research quality and research methods, sample size, period of intervention, measurements of quality control for intervention, compliance rate, lost-to-follow-up rate and publications based on the research. Moreover, it was also used to analyze the synthetical quality of high risk areas in association with the factors of institution setting, the quality of cancer registry, the quality of scientific research, the quality of publication and the awards.In the second part, the quality control was summarized and discussed in the aspects of study subjects selection, follow-up, improvement of compliance, data management and preservation by the Monte Carlo methods and Time Series analysis, based on an intervention trial in Linqu County.Results: In the part one, the quality of scientific research was evaluated with the RSR test according to the variables of research method (x1), sample size (x2), period of intervention (x3), measurements of quality control for intervention (x4), compliance rate (x5), lost-to-follow-up rate (x6) and publications based on the research (x7). The RSR value in Linqu County, Linzhou County, Qidong County, Changle County, Fusui County and Yanting County was 84, 71, 64, 48, 46, 46 and 40, respectively. The standardized model for the quality of scientific research was Y=0.119x1+0.212x2+0.210x3+0.142x4+0.209x5+0.165x6+0.219x7.The synthetical quality was evaluated with the RSR test according to the factors of institution setting (x1), the quality of cancer registry (x2), the quality of scientific research (x3), the quality of publication (x4) and the awards (x5). The RSR value in Qidong County, Linzhou County, Linqu County, Changle County, Jiashan County, Fusui County and Yanting County was 84, 71, 64, 48, 46, 46 and 40, respectively. The standardized model for the synthetical quality of high risk areas for cancer was Y=0.055x1+0.295x2+0.315x3+0.403x4+0.241x5.In the part two, it was considered that a high-quality intervention trial should be improved in following aspects:First, the subjects should be selected strictly by eligibility criteria and the replacers should be excluded from the cohort as much as possible.Second, the responsible staff should be recruited among local residents and their quality should be controlled by various standard measures.Third, low lost-to-follow-up rate and high compliance rate could avoid or decrease the bias, which may influence the end point of the trial.Fourth, the confounding factors should be collected and controlled when conclusions of the study are made.Conclusions: In this study, the basic and ideal model of sustainable development of high risk areas for cancer was brought forward by the evaluation of scientific research quality and synthetical quality. Moreover, the effective quality control of intervention trial in high risk areas for cancer was summarized and discussed, which may contribute the continuation of the developments of high risk areas for cancer in China.