Department of Breast Screening, Cancer Registry of Norway, Oslo, Norway; Faculty of of Health Sciences, Oslo Metropolitan University, Oslo, Norway.
Department of Breast Screening, Cancer Registry of Norway, Oslo, Norway.
Lancet Oncol. 2019 Jun;20(6):795-805. doi: 10.1016/S1470-2045(19)30161-5. Epub 2019 May 8.
Digital breast tomosynthesis is an advancement of mammography, and has the potential to overcome limitations of standard digital mammography. This study aimed to compare first-generation digital breast tomo-synthesis including two-dimensional (2D) synthetic mammograms versus digital mammography in a population-based screening programme.
BreastScreen Norway offers all women aged 50-69 years two-view (craniocaudal and mediolateral oblique) mammographic screening every 2 years and does independent double reading with consensus. We asked all 32 976 women who attended the programme in Bergen in 2016-17, to participate in this randomised, controlled trial with a parallel group design. A study-specific software was developed to allocate women to either digital breast tomosynthesis or digital mammography using a 1:1 simple randomisation method based on participants' unique national identity numbers. The interviewing radiographer did the randomisation by entering the number into the software. Randomisation was done after consent and was therefore concealed from both the women and the radiographer at the time of consent; the algorithm was not disclosed to radiographers during the recruitment period. All data needed for analyses were complete 12 months after the recruitment period ended. The primary outcome measure was screen-detected breast cancer, stratified by screening technique (ie, digital breast tomosynthesis and digital mammography). A log-binomial regression model was used to estimate the efficacy of digital breast tomosynthesis versus digital mammography, defined as the crude risk ratios (RRs) with 95% CIs for screen-detected breast cancer for women screened during the recruitment period. A per-protocol approach was used in the analyses. This trial is registered at ClinicalTrials.gov, number NCT02835625, and is closed to accrual.
Between, Jan 14, 2016, and Dec 31, 2017, 44 266 women were invited to the screening programme in Bergen, and 32 976 (74·5%) attended. After excluding women with breast implants and women who did not consent to participate, 29 453 (89·3%) were eligible for electronic randomisation. 14 734 women were allocated to digital breast tomosynthesis and 14 719 to digital mammography. After randomisation, women with a previous breast cancer were excluded (digital breast tomosynthesis group n=314, digital mammography group n=316), women with metastases from melanoma (digital breast tomosynthesis group n=1), and women who informed the radiographer about breast symptoms after providing consent (digital breast tomosynthesis group n=39, digital mammography group n=34). After exclusions, information from 28 749 women were included in the analyses (digital breast tomosynthesis group n=14 380, digital mammography group n=14 369). The proportion of screen-detected breast cancer among the screened women did not differ between the two groups (95 [0·66%, 0·53-0·79] of 14 380 vs 87 [0·61%, 0·48-0·73] of 14 369; RR 1·09, 95% CI 0·82-1·46; p=0·56).
This study indicated that digital breast tomosynthesis including synthetic 2D mammograms was not significantly different from standard digital mammography as a screening tool for the detection of breast cancer in a population-based screening programme. Economic analyses and follow-up studies on interval and consecutive round screen-detected breast cancers are needed to better understand the effect of digital breast tomosynthesis in population-based breast cancer screening.
Cancer Registry of Norway, Department of Radiology at Haukeland University Hospital, University of Oslo, and Research Council of Norway.
数字乳腺断层合成是乳腺摄影的一项进步，有可能克服标准数字乳腺摄影的局限性。本研究旨在比较第一代数字乳腺断层合成（包括二维（2D）合成乳房 X 线照片）与基于人群的筛查计划中的数字乳腺摄影。
挪威乳腺筛查为 50-69 岁的所有女性每 2 年提供两次视图（头尾和内外斜）乳腺 X 线筛查，并进行独立的双读并达成共识。我们要求 2016-17 年在卑尔根参加该计划的所有 32976 名女性参加这项随机、对照试验，采用平行组设计。开发了一种专用软件，使用参与者独特的国家身份证号码，以 1:1 的简单随机化方法将女性分配到数字乳腺断层合成或数字乳腺摄影中。采访放射技师通过将数字输入软件进行随机化。在同意后进行随机化，因此在同意时对妇女和放射技师都保密；在招募期间，未向放射技师透露算法。在招募期结束后 12 个月，完成了所有分析所需的数据。主要观察指标是筛查发现的乳腺癌，按筛查技术（即数字乳腺断层合成和数字乳腺摄影）分层。使用对数二项回归模型估计数字乳腺断层合成与数字乳腺摄影的疗效，定义为招募期筛查女性的数字乳腺断层合成与数字乳腺摄影的粗风险比（RR）和 95%CI 筛查发现的乳腺癌。在分析中使用了符合方案的方法。这项试验在 ClinicalTrials.gov 注册，编号为 NCT02835625，现已停止招募。
2016 年 1 月 14 日至 2017 年 12 月 31 日，卑尔根筛查计划邀请了 44266 名女性，32976 名（74.5%）参加。排除乳房植入物的女性和不同意参加的女性后，有 29453 名（89.3%）符合电子随机化条件。14734 名女性被分配到数字乳腺断层合成组，14719 名女性被分配到数字乳腺摄影组。随机化后，排除了有乳腺癌病史的女性（数字乳腺断层合成组 n=314，数字乳腺摄影组 n=316）、黑色素瘤转移的女性（数字乳腺断层合成组 n=1）和在提供同意后告知放射技师乳房症状的女性（数字乳腺断层合成组 n=39，数字乳腺摄影组 n=34）。排除后，28749 名妇女的信息纳入分析（数字乳腺断层合成组 n=14380，数字乳腺摄影组 n=14369）。筛查女性中筛查发现的乳腺癌比例在两组之间没有差异（数字乳腺断层合成组 95[0.66%，0.53-0.79]例/14380 例 vs 数字乳腺摄影组 87[0.61%，0.48-0.73]例/14369 例；RR 1.09，95%CI 0.82-1.46；p=0.56）。
这项研究表明，在基于人群的筛查计划中，数字乳腺断层合成（包括合成 2D 乳房 X 线照片）与标准数字乳腺摄影作为乳腺癌筛查工具没有显著差异。需要进行经济分析和对间隔和连续轮次筛查发现的乳腺癌的随访研究，以更好地了解数字乳腺断层合成在基于人群的乳腺癌筛查中的效果。
挪威癌症登记处、豪克兰大学医院放射科、奥斯陆大学和挪威研究理事会。
