BACKGROUND Although reproductive history is recognised to affect the risk of breast cancer, current breast cancer screening guidelines do not consider risk differences by this important factor. As there is a need for an earlier screening in women at increased risk of breast cancer, we provided evidence-based risk-adapted starting age of screening based on different reproductive profiles. MATERIAL AND METHODS We conducted a nationwide cohort study including 5,099,172 Swedish women born after 1931. Records of study participants in Swedish Cancer Registry, Multi-generation Register, Cause of Death Register, and national censuses (follow-up, 1958-2015) have been linked. We used 10-year cumulative risk of breast cancer curves to determine the age at which women with different reproductive factors attained the risk level at which breast screening is usually recommended. RESULTS The 10-year cumulative risk of breast cancer at age 40, 45 and 50 years in the general population, at which current screening guidelines recommend screening was calculated. We found that women with various reproductive factors (defined by parity and age at first birth) obtained this level of risk at different ages. The difference was between nine years later and three years earlier. CONCLUSIONS This study provides the age at which women with particular reproductive profile could start risk-adapted breast cancer screening. This supplies novel information for clinicians and women about when to start breast cancer screening and is an important step towards a personalised screening.

中文翻译：

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根据女性生殖状况按风险量身定制的乳腺癌筛查起始年龄：一项全国性队列研究。

背景技术尽管公认生殖史会影响乳腺癌的风险，但是当前的乳腺癌筛查指南并未通过这一重要因素来考虑风险差异。由于需要对罹患乳腺癌风险增加的女性进行早期筛查，因此我们根据不同的生殖状况，提供了基于证据的，适应风险的筛查起始年龄。材料和方法我们进行了一项全国性队列研究，其中包括1931年后出生的5,099,172瑞典妇女。瑞典癌症登记处，多代登记处，死亡原因登记处和国家人口普查（随访，1958-2015年）的研究参与者的记录均已记录在案。链接。我们使用了10年的乳腺癌累积风险曲线来确定具有不同生殖因素的女性达到建议进行乳房筛查的风险水平的年龄。结果在一般人群中，分别计算了40、45和50岁的10年乳腺癌累积风险，并根据当前的筛查指南建议进行筛查。我们发现，具有各种生殖因素（由第一胎的性别和年龄定义）的妇女在不同年龄时都达到了这一风险水平。区别在于九年后和三年前。结论本研究提供了具有特定生殖特征的女性可以开始进行风险适应性乳腺癌筛查的年龄。