Department of Surgery, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
Center for Cohort Studies, Total Healthcare Center, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
Cancer. 2020 Nov 1;126(21):4687-4696. doi: 10.1002/cncr.33138. Epub 2020 Aug 7.
The risk of breast cancer related to changes in breast density over time, including its regression and persistence, remains controversial. The authors investigated the relationship between breast density and its changes over time with the development of breast cancer in premenopausal and postmenopausal women.
The current cohort study included 74,249 middle-aged Korean women (aged ≥35 years) who were free of breast cancer at baseline and who underwent repeated screening mammograms. Mammographic breast density was categorized according to the American College of Radiology Breast Imaging Reporting and Data System (BI-RADS). A dense breast was defined as heterogeneously dense or extremely dense, and changes in dense breasts between baseline and subsequent follow-up were classified as none, developed, regressed, or persistent dense breast.
During a median follow-up of 6.1 years (interquartile range, 4.1-8.8 years), a total of 803 incident breast cancers were identified. Baseline breast density was found to be positively associated with incident breast cancer in a dose-response manner, and this association did not significantly differ by menopausal status. The multivariable-adjusted hazard ratios (HRs) for breast cancer comparing "heterogeneously dense" and "extremely dense" categories with the nondense category were 1.96 (95% confidence interval [95% CI], 1.40-2.75) and 2.86 (95% CI, 2.04-4.01), respectively. With respect to changes in dense breasts over time, multivariable-adjusted HRs for breast cancer comparing persistent dense breast with none were 2.37 (95% CI, 1.34-4.21) in premenopausal women and 3.61 (95% CI, 1.78-7.30) in postmenopausal women.
Both baseline dense breasts and their persistence over time were found to be strongly associated with an increased risk of incident breast cancer in premenopausal and postmenopausal women.
Both baseline breast density and its changes over time were found to be independently associated with the risk of breast cancer in both premenopausal and postmenopausal women. The risk of incident breast cancer increased in women with persistent dense breasts, whereas the breast cancer risk decreased as dense breasts regressed. The findings of the current study support that both dense breasts at baseline and their persistence over time are independent risk factors for developing breast cancer.
乳腺癌与随时间变化的乳腺密度变化相关，包括其消退和持续存在，其风险仍然存在争议。作者研究了绝经前和绝经后妇女中乳腺密度及其随时间变化与乳腺癌发展之间的关系。
当前的队列研究包括 74249 名中年韩国女性（年龄≥35 岁），她们在基线时没有乳腺癌，并接受了重复的筛查乳房 X 光检查。根据美国放射学院乳腺成像报告和数据系统（BI-RADS）对乳房密度进行分类。致密乳房定义为不均匀致密或极度致密，并且在基线和随后的随访之间致密乳房的变化分为无、发展、消退或持续致密乳房。
在中位随访 6.1 年（四分位间距，4.1-8.8 年）期间，共发现 803 例乳腺癌新发病例。乳腺密度与乳腺癌的发生呈剂量反应关系，且这种关系在绝经状态下没有显著差异。与非致密组相比，“不均匀致密”和“极度致密”组乳腺癌的多变量调整后的风险比（HR）分别为 1.96（95%置信区间[95%CI]，1.40-2.75）和 2.86（95%CI，2.04-4.01）。关于致密乳房随时间的变化，与无致密乳房相比，绝经前女性持续性致密乳房的多变量调整 HR 为 2.37（95%CI，1.34-4.21），绝经后女性为 3.61（95%CI，1.78-7.30）。
基线致密乳房及其随时间的持续存在均与绝经前和绝经后妇女乳腺癌发生的风险增加密切相关。
基线乳腺密度及其随时间的变化均与绝经前和绝经后妇女的乳腺癌风险独立相关。持续性致密乳房的乳腺癌发病风险增加，而致密乳房消退时乳腺癌发病风险降低。本研究的结果支持基线致密乳房及其随时间的持续存在是乳腺癌发生的独立危险因素。
