目的:比较乳腺癌群体筛查和机会性筛查两种模式的人群特点、筛查阳性率、乳腺癌检出率、早期乳腺癌比例及筛查费用。方法:本研究为前瞻性多中心队列研究，研究时间为2014年1月1日至2016年12月31日。分别入组群体筛查和机会性筛查受试者，填写调查问卷表，并进行每年1次乳腺体检及乳腺超声检查，共完成3轮筛查，采用χ2检验、Fisher确切概率法和Wilcoxon秩和检验比较两组人群的特点及筛查结果。结果:共入组受试者20 080人。群体筛查组完成3轮筛查的人数分别为9 434人（100%），8 111人（85.98%）和3 940人（41.76%）；机会性筛查组分别为10 646人（100%），6 209人（58.32%）和2 988人（28.07%）。机会性筛查组中产后哺乳时间<3个月（1 275/9 796比1 061/8 860，χ2=4.597，n P=0.032）、未生育（850/10 646比574/9 434，χ2=27.400，n P<0.01）、有流产史（6 384/10 646比5 062/9 434，χ2=81.232，n P<0.01）、绝经后（2 776/10 646比2 217/9 434，χ2=17.757，n P<0.01）、口服避孕药≥6个月（171/10 646比77/9 434，χ2=25.593，n P<0.01）及一级亲属乳腺癌阳性家族史（464/10 646比236/9 434，χ2=51.257，n P<0.01）比例高于群体筛查组。机会性筛查组筛查阳性率（514/10 646比128/9 434，χ2=194.736，n P<0.01）、乳腺癌检出率（158/10 646比13/9 434，χ2=107.374，n P<0.01）和活检阳性率（158/452比13/87，χ2=13.491，n P<0.01）高于群体筛查组。群体筛查组早期乳腺癌（0期和Ⅰ期）比例高于机会性筛查组（10/12比66/141，χ2=5.902，n P=0.015）。群体筛查组发现每1例乳腺癌的平均费用为215 038元，是机会性筛查组15 799元的13.6倍。机会性筛查组基层医院的活检阳性率低于大型医院（79/267比79/185，χ2=8.267，n P=0.004），而群体筛查组两者无明显差异（6/37比7/50，χ2=0.082，n P=0.774）。n 结论:乳腺癌筛查可以早期发现乳腺癌。机会性筛查具有受试者乳腺癌高危因素比例高、筛查阳性率高、乳腺癌检出率高、活检阳性率高、筛查费用低的特点。但是，机会性筛查的早期乳腺癌比例低于群体筛查，基层医院开展机会性筛查时活检阳性率较低。两种筛查模式各有优势，需要有机结合，取长补短。“,”Objective:To compare the population characteristics, the positive rate of screening, the detection rate of breast cancer, early diagnosis rate and the cost between the mass screening group and opportunistic screening group of breast cancer.Methods:This study is a prospective multicenter cohort study conducted from January 1, 2014 to December 31, 2016. The participants were enrolled for mass screening or opportunistic screening of breast cancer. After completing the questionnaire, all the participants received breast physical examination and breast ultrasound examination every year for 3 rounds by year. The participants′ characteristics and screening results of the two groups were compared by χn 2 test, Fisher exact test or Wilcoxon rank-sum test.n Results:A total of 20 080 subjects were enrolled. In the mass screening group, 9 434 (100%), 8 111 (85.98%) and 3 940 (41.76%) cases completed the 3 rounds of screening, and 10 646 (100%), 6 209 (58.32%) and 2 988 (28.07%) cases in the opportunistic screening group, respectively. In the opportunistic screening group, the proportions of less than 3 months lactation (1 275/9 796 n vs. 1 061/8 860, χ2=4.597, n P=0.032), non-fertility (850/10 646n vs.574/9 434, χ2=27.400, n P<0.01), abortion history (6 384/10 646n vs.5 062/9 434, χ2=81.232, n P<0.01), postmenopausal (2 776/10 646n vs. 2 217/9 434, χ2=17.757, n P6 months) (171/10 646n vs.χ2=25.593, n P<0.01) and family history of breast cancer in first-degree relatives (464/10 646n vs. 236/9 434, χ2=51.257, n P<0.01) were significantly higher than those in mass screening group. The positive rate of screening (514/10 646n vs. 128/9 434, χ2=194.736, n P<0.01), the detection rate of breast cancer (158/10 646n vs. 13/9 434, χ2=107.374, n P<0.01), and positive rate of biopsy (158/452n vs. 13/87, χ2=13.491, n P<0.01) in the opportunistic screening group were significantly higher than those of the mass screening group. The early diagnosis rate of the mass screening group was significantly higher than the opportunistic screening group (10/12n vs. 66/141, χ2=5.902, n P=0.015). The average cost for detecting each breast cancer case of the mass screening group was 215 038 CNY, which was 13.6 times of the opportunistic screening group (15 799 CNY/case). In the opportunistic screening group, the positive rate of biopsy in primary hospitals was significantly lower than that in large-volume hospitals (79/267 n vs. 79/185, 42.7%, χ2=8.267, n P=0.004), but there was no significant difference in the mass screening group (6/37 n vs. 7/50, χ2=0.082, n P=0.774).n Conclusions:Breast cancer screening can improve early detection rate. Compared with the mass screening mode, the opportunistic screening mode has the advantages of higher proportion of high-risk factors, higher positive rate of screening, higher detection rate of breast cancer, higher positive rate of biopsy, and lower cost of screening. However, the early diagnosis rate of breast cancer of opportunistic screening is lower than that of mass screening. The positive rate of opportunistic screening in primary hospitals is lower than that of large-volume hospitals. The two screening modes have their own advantages and should be chosen according to local conditions of different regions in China.