Characteristics of eligible studies included in this meta-analysis.

RCT: randomized controlled trials; MRM: modified radical mastectomy; SM: simple mastectomyCharacteristics of eligible studies included in this meta-analysis.RCT：随机对照试验（randomized controlled trials）；MRM：改良根治性乳房切除术（modified radical mastectomy）；SM：单纯乳房切除术（simple mastectomy）。本荟萃分析纳入的符合入选标准的研究的特征。