| Evidence classification method： |
The level of evidence grading system was developed by referring to the GRADE system combined with findings in clinical studies in China. The levels are classified as Category I, II, III, and IV to quantify the evaluation of the reliability of the evidence by experts on the compiling committees. To make these guidelines accessible in clinical practice in China, the expert panel preferentially selected Category I and II evidence, as indicated in the guideline evaluation system.
I Based on high-level prospective randomized controlled clinical trials, observational studies or meta-analyses with large sample sizes, internationally-recognized current guidelines and consensus statements, published guidelines and consensus statements from national societies or associations, Chinese population-based studies of the above types published in SCI journals, MEDLINE journals, and Chinese series journals
II Based on low-level randomized clinical trials, well-designed non-controlled trials or cohort studies, inter-continental professional association guidelines and international conference expert consensus statements, published guidelines and consensus statements from national regional societies or associations, Chinese population-based studies of the above types published in PKU core journals
III Based on case-control studies or retrospective studies, published guidelines and consensus statements from national professional associations, and provincial societies or associations, Chinese population-based studies of the above types published in source journals for Chinese scientific and technical papers and citations
IV Based on case reports, scientific hypotheses, regional expert consensus statements and published guidelines and consensus statements from national local societies or associations, Chinese population-based studies of the above types published in non-aforementioned core journals |
| Purpose of the guideline: |
Breast cancer is the most common malignancy among women in China, and there has been an obvisous ever-increasing trend of incidence over the past decades, resulting in a great social and economic burden. Approximately 304 thousands of new breast cancer cases were diagnosed in 2015 in China, ranking the first leading cancer diagnosis and accounting for 17.1% of all new cancers in women. [1,2] Currently, image-based screening program, using ultrasound and/or mammography, has been proposed as one of the most important strategies and become the most common efforts to lower breast cancer burden in China, though primary prevention measures are still lacking. Both US Preventive Services Task Force (USPSTF)[3] and National Comprehensive Cancer Network (NCCN) clinical practice guidelines[4] have made recommendations on risk assessment to identify women at increased risk for breast cancer, for whom risk-based cancer screening and/or risk-reducing medication use should be provided in order to lower the individual breast cancer risk. |
