Department of Head and Neck and Endocrine Surgery, Faculty of Medicine, University of Alexandria, Alexandria, Egypt.
Department of Breast Surgery, St Bartholomew Hospital (Barts), London, UK.
Breast Cancer Res Treat. 2019 Sep;177(2):251-276. doi: 10.1007/s10549-019-05300-1. Epub 2019 Jun 8.
It is well established that high mammographic density (MD), when adjusted for age and body mass index, is one of the strongest known risk factors for breast cancer (BC), and also associates with higher incidence of interval cancers in screening due to the masking of early mammographic abnormalities. Increasing research is being undertaken to determine the underlying histological and biochemical determinants of MD and their consequences for BC pathogenesis, anticipating that improved mechanistic insights may lead to novel preventative or treatment interventions. At the same time, technological advances in digital and contrast mammography are such that the validity of well-established relationships needs to be re-examined in this context.
With attention to old versus new technologies, we conducted a literature review to summarise the relationships between clinicopathologic features of BC and the density of the surrounding breast tissue on mammography, including the associations with BC biological features inclusive of subtype, and implications for the clinical disease course encompassing relapse, progression, treatment response and survival.
There is reasonable evidence to support positive relationships between high MD (HMD) and tumour size, lymph node positivity and local relapse in the absence of radiotherapy, but not between HMD and LVI, regional relapse or distant metastasis. Conflicting data exist for associations of HMD with tumour location, grade, intrinsic subtype, receptor status, second primary incidence and survival, which need further confirmatory studies. We did not identify any relationships that did not hold up when data involving newer imaging techniques were employed in analysis.
众所周知，高乳房 X 光密度（MD）在调整年龄和体重指数后，是乳腺癌（BC）最强的已知风险因素之一，并且由于早期乳房 X 光异常的掩盖，与筛查中间隔性癌症的发生率更高有关。越来越多的研究正在进行，以确定 MD 的潜在组织学和生化决定因素及其对 BC 发病机制的影响，预计对机制的深入了解可能会导致新的预防或治疗干预措施。与此同时，数字和对比乳房 X 光技术的进步使得在这种情况下，需要重新检查既定关系的有效性。
我们注意到新旧技术，进行了文献综述，总结了 BC 的临床病理特征与乳房 X 光片中周围乳腺组织密度之间的关系，包括与 BC 生物学特征（包括亚型）的关联，以及对临床疾病过程的影响，包括复发、进展、治疗反应和生存。
有合理的证据支持高 MD（HMD）与肿瘤大小、淋巴结阳性和放射治疗后局部复发之间的正相关关系，但与 LVI、区域复发或远处转移之间没有相关性。HMD 与肿瘤位置、分级、内在亚型、受体状态、第二原发癌发生率和生存之间的关联存在相互矛盾的数据，需要进一步的证实性研究。我们没有发现任何在分析中使用更新的成像技术数据时不成立的关系。
