ABSTRACT
Background: Epidemiological and clinical cancer research is essential to understanding tumour behaviour and developing new therapies in oncology. However, several countries including Brazil as well as many other regions of the world have limited participation in cancer research. Despite 625,000 new cancer cases recorded in Brazil in 2022, only 2.2% of ongoing cancer clinical trials are available in the country. We conducted an online survey to describe physician engagement with research and to identify the main barriers precluding participation in and conduct of clinical cancer research in the country. Methods: An anonymous online survey of 23 objective questions was sent by e-mail to Brazilian members of the Latin American Cooperative Oncology Group and the Brazilian Society of Clinical Oncology. The first 13 questions addressed demographic information, medical training and previous research participation. In the second part, the main barriers to engagement and participation in clinical trials in Brazil were addressed. Continuous variables were measured by median and range. Analyses were performed using SAS statistical software (version 9.4; SAS Institute, Inc. Cary, NC). Results: 109 physicians answered the survey. Most participants were oncologists (N = 98, 89.9%), living in capital cities (N = 84, 77.1%), were from the Southeast region of Brazil (N = 63, 57.8%) and worked at institutions providing exclusively private healthcare (N = 59, 54.1%). Of the 109 respondents, 83 (76.1%) reported working in research centres (as investigators or sub-investigators). Surprisingly, 31.2% of physicians recognised they invite less than 1% of their patients to participate in clinical trials, even though 98 (89.9%) considered the participation of patients in clinical trials extremely relevant. The main barriers compromising the conduct of research in the country were the low number of available trials (48.2%) and the lack of qualified human resources to staff research sites (22.9%). Other reported barriers were the lengthy regulatory approval process (42.2%), followed by a lack of awareness of clinical research by patients resulting in low recruitment rates (24.1%). Of the 26 (23.8%) respondents not working with research, 25 (96.1%) reported interest in being involved, 31.8% have tried participating in research and 62.4% reported limited knowledge of trial procedures. Conclusion: These results suggest a clear need to further engage physicians in clinical research activities in Brazil. Patient education strategies should improve the low recruitment rates and secondarily increase the number of proposed trials in the country.
ABSTRACT
Overpopulation and environmental degradation due to inadequate resource-use are outcomes of human's ecosystem engineering that has profoundly modified the world's landscape. Despite the age-old concern that unchecked population and economic growth may be unsustainable, the prospect of societal collapse remains contentious today. Contrasting with the usual approach to modeling human-nature interactions, which are based on the Lotka-Volterra predator-prey model with humans as the predators and nature as the prey, here we address this issue using a discrete-time population dynamics model of ecosystem engineers. The growth of the population of engineers is modeled by the Beverton-Holt equation with a density-dependent carrying capacity that is proportional to the number of usable habitats. These habitats (e.g., farms) are the products of the work of the individuals on the virgin habitats (e.g., native forests), hence the denomination engineers of ecosystems to those agents. The human-made habitats decay into degraded habitats, which eventually regenerate into virgin habitats. For slow regeneration resources, we find that the dynamics is dominated by rounds of prosperity and collapse, in which the population reaches vanishing small densities. However, increase of the efficiency of the engineers to explore the resources eliminates the dangerous oscillatory patterns of feast and famine and leads to a stable equilibrium that balances population growth and resource availability. This finding supports the viewpoint of growth optimists that technological progress may avoid collapse.
