Guidelines for early detection of breast cancer in Brazil. I - Development methods

Clinical guidelines are traditionally drafted by expert consensus. The benefits of mammographic screening have been questioned in recent years, owing to biases detected in the clinical trials that popularized its widespread use. Meanwhile, growing body of evidence on harms associated with mammographic screening also required a new approach, taking into account the uncertainties on the benefits and a balance between the gains and possible harms from screening. This article discusses the development of the new guidelines for early detection of breast cancer in Brazil, with details on the drafting methods and implications for the new recommendations. The new methodology features systematic literature reviews, assessment of the validity of the evidence, and the balance between each intervention's risks and benefits, ensuring greater transparency, reproducibility, and validity in the drafting process. The new guidelines also include recommendations for cases with suspicious signs and symptoms. The authors provide a detailed discussion of the advantages of the approach as compared to the traditional expert consensus model, as well as the methods' limitations and disadvantages. They also address the implications of various decisions, such as choices on study designs, screening effectiveness outcomes, definition of overdiagnosis, and methods for calculation.