目的通过对加拿大新斯科舍省乳腺间期癌病例的影像回顾来确定间期癌发生率与漏诊率。材料与方法研究项目获机构审查委员会批准。间期癌病例来自1991年—2004年在新斯科舍省参与乳腺筛查项目的女性,参与者年龄为40～69岁。对每一病例,均会从有经验的放射专家库中随机选取3位放射专家对乳腺X线摄影筛查为阴性的病例进行盲法审查。将病例按正常和不正常归类,对后者要进一步调查随访。至少有2位放射专家的复审结果是正常的病例方可定为间期癌。根据妇女年龄段及筛查间期(年龄40～49岁,间期1年;年龄50～69岁,间期1年和2年)分别计算实际间期癌发生率和漏诊率。结果每年进行筛查者,每1000例筛查妇女的漏诊率为间期癌发生率的一半(40～49岁,0.45∶0.93;50～69岁,1.08∶2.22)。每两年筛查一次的50～69岁的妇女中,每1000名筛查妇女的漏诊率为间期癌发生率的1/3(0.90∶3.15)。同样的,每10000个筛查妇女中,40～49岁组漏诊率也是间期癌发生率的一半(1.95∶3.99),50～69岁组妇女漏诊率为间期癌的1/3(3.34∶10.44)。结论在筛查项目中,作为持续质量保证的一部分,间期癌的发生率应与癌症的漏诊率区别开来。 Objective To determine the incidence of cancer and the rate of misdiagnosis through a retrospective review of breast cancer cases in Nova Scotia, Canada. Materials and Methods Research Project Approved by Institutional Review Board. The cases of intercostal cancer were from women who participated in the Breast Screening Program in Nova Scotia from 1991 to 2004. The participants ranged in age from 40 to 69 years. For each case, three radiologists were randomly selected from a pool of experienced radiologists to conduct a blinded review of mammography-negative cases. The cases were classified as normal and abnormal, the latter should be further investigated for follow-up. At least two radiologists review the results of normal cases can be scheduled for the interval cancer. The actual incidence of cancer and misdiagnosis were calculated according to the age of women and screening interval (40 to 49 years of age, 1 year of interval; 50 to 69 years of age, 1 year and 2 years of interval). RESULTS: In the annual screening, the rate of misdiagnosis per 1000 screening women was half of the incidence of intercostal cancer (40-49, 0.45: 0.93; 50-69, 1.08: 2.22). Of women aged 50-69 who had been screened every two years, the rate of misdiagnosis per 1,000 women was one-third (0.90: 3.15) for the incidence of intercurrent cancer. Similarly, for every 10,000 women screened, the rate of misdiagnosis in the 40-49 age group was also half as high as that in the intermediate stage (1.95: 3.99), and the rate of misdiagnosis in the 50-69 age group was 1/3 (3.34) : 10.44). Conclusions In screening programs, the incidence of intercostal cancer should be distinguished from the rate of misdiagnosis of cancer as part of an ongoing QA.