Cumulative incidence of advanced breast cancer in women aged 40-49 years in the Japan Strategic Anti-cancer Randomised Trial (J-START) of adjunctive ultrasonography: a prespecified secondary analysis.

This report aims to evaluate the long-term effect of adjunctive ultrasonography screening on the cumulative incidenceof advanced breast cancer as a prespecified secondary outcome of J-START.

本报告旨在评估辅助超声筛查对J-START预先设定的次要结果——晚期乳腺癌累积发病率的长期影响。

Methods

We enrolled asymptomatic women in 42 study sites in 23 of 47 prefectures in Japan.

我们在日本47个县中的23个县的42个研究地点招募了无症状的女性。

Eligible women were aged 40-49 years without a history of breast cancer, including in-situ cancer, or other cancers in the previous 5 years, and who had a life expectancy of more than 5 years.

符合条件的女性年龄在40-49岁之间，过去5年内没有乳腺癌（包括原位癌）或其他癌症的病史，并且预期寿命超过5年。

Participants were assigned in a 1:1 ratio to undergo ultrasonography with mammography (intervention group) or mammography alone (control group) twice during a 2-year screening period by individual or cluster randomisation.

参与者以1:1的比例被分配接受超声波检查联合乳房X线摄影（干预组）或仅乳房X线摄影（对照组），在2年的筛查期间通过个体或群组随机化进行两次筛查。

Participants attended an initial screening appointment and were then asked to return for a second screening after 2 years.

参与者参加了初步筛查预约，然后被要求在2年后返回进行第二次筛查。

This prespecified secondary analysis assessed the cumulative incidenceof stage 2 or higher breast cancers based on the TNM classification up to data cutoff on Oct 4, 2024.

这项预先设定的次要分析评估了基于TNM分期系统，截至2024年10月4日数据截止时，2期或更高级别乳腺癌的累积发生率。

Results

Between Aug 2, 2007, and March 31, 2011, 72 661 asymptomatic women aged 40-49 years were randomly assigned (36 723 in the intervention group and 35 938 in the control group).

在2007年8月2日至2011年3月31日期间，共有72,661名40至49岁的无症状女性被随机分配（干预组36,723人，对照组35,938人）。

Median follow-up for this secondary analysis was 11·4 years (range 0·0-16·1; IQR 9·3-12·9) in the intervention group and 11·3 years (0·0-16·1; 8·9-12·9) in the control group.

本次次要分析的中位随访时间为干预组11.4年（范围0.0-16.1年；四分位数间距9.3-12.9年），对照组为11.3年（范围0.0-16.1年；四分位数间距8.9-12.9年）。

Of 894 breast cancers detected in the intervention group, 234 (26%) were advanced cancers, compared with 277 (33%) of 843 detected breast cancers in the control group (hazard ratio0·83 [95·6% CI 0·70-0·98]; p=0·026).

在干预组检测到的894例乳腺癌中，有234例（26%）为晚期癌症，而在对照组检测到的843例乳腺癌中，有277例（33%）为晚期癌症（风险比0.83 [95.6% CI 0.70-0.98]；p=0.026）。

Kaplan-Meier curves suggested a violation of the proportional hazards assumption, with a significant difference in advanced cancer incidenceonly between 48 months and 96 months.

Kaplan-Meier曲线显示违反了比例风险假设，仅在48个月至96个月之间观察到晚期癌症发生率的显著差异。

Divergence between groups emerged around year four, widened until year eight, and remained stable thereafter.

两组之间的差异在第四年左右开始显现，到第八年时差异扩大，并在此后保持稳定。

interpretation

Adjunctive ultrasonography reduced the cumulative incidenceof advanced breast cancer in women aged 40-49 years.

辅助性超声波检查降低了40-49岁女性晚期乳腺癌的累积发生率。

These findings highlight the potential value of integrating adjunctive ultrasonography into screening programmes for women with dense breast tissue, particularly in Asian populations, and could inform future breast cancer screening guidelines.

这些发现突显了将辅助性超声波检查整合到具有致密乳腺组织的女性筛查计划中的潜在价值，特别是在亚洲人群中，这可以为未来的乳腺癌筛查指南提供信息。

funding

The Ministry of Health, Labor, and Welfare (Japan) and Japan Agency for Medical Research and Development.

日本厚生劳动省和日本医疗研究开发机构。