Hartman Mikael, Czene Kamila, Reilly Marie, Bergh Jonas, Lagiou Pagona, Trichopoulos Dimitrios, Adami Hans-Olov, Hall Per
Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden.
Lancet Oncol. 2005 Jun;6(6):377-82. doi: 10.1016/S1470-2045(05)70174-1.
Women with breast cancer are at high risk of bilateral breast cancer. We aimed to assess the incidence of bilateral breast cancer in relation to age and time since diagnosis of first cancer.
We analysed a population-based cohort of 123757 women with a first primary breast cancer diagnosed in Sweden from 1970 to 2000 for frequency of bilateral breast cancers and deaths by means of record linkage. Second primary breast cancers were categorised as synchronous bilateral breast cancers if diagnosed within 3 months of the first primary cancer or as metachronous if diagnosed more than 3 months after diagnosis of first primary cancer.
We identified 6550 women who had developed bilateral breast cancer. Age-incidence patterns of synchronous and unilateral breast cancer were similar, although the absolute rates of synchronous bilateral cancer were 50-100 times lower than those of unilateral cancer. A woman aged 80 years or older is at least twice as likely to be diagnosed with synchronous bilateral breast cancer than is a woman younger than 40 years. In the first 20 years after diagnosis of primary breast cancer, incidence of metachronous bilateral cancer decreased from about 800 per 10(5) person-years to 400 per 10(5) person-years in patients diagnosed with primary breast cancer before the age of 45 years, whereas incidence remained at 500-600 per 10(5) person-years in those age 45 years or older at diagnosis. After 30 years' follow-up, cumulative risk of metachronous bilateral breast cancer was about 15% irrespective of age at first primary breast cancer.
The higher than expected risk of synchronous bilateral breast cancer could be explained by non-genetic factors. By contrast, incidence of metachronous bilateral cancer fits neither a model of highly penetrant genes nor aggregation of environmental risk factors.
乳腺癌女性患双侧乳腺癌的风险很高。我们旨在评估双侧乳腺癌的发病率与年龄及首次癌症诊断后的时间之间的关系。
我们通过记录链接分析了1970年至2000年在瑞典诊断出首例原发性乳腺癌的123757名女性的人群队列，以了解双侧乳腺癌的发生频率和死亡情况。如果第二原发性乳腺癌在首例原发性癌症诊断后的3个月内被诊断出来，则被归类为同步双侧乳腺癌；如果在首例原发性癌症诊断超过3个月后被诊断出来，则被归类为异时性乳腺癌。
我们确定了6550名患双侧乳腺癌的女性。同步性和单侧乳腺癌的年龄发病率模式相似，尽管同步双侧乳腺癌的绝对发病率比单侧癌症低50至100倍。80岁及以上的女性被诊断为同步双侧乳腺癌的可能性至少是40岁以下女性的两倍。在原发性乳腺癌诊断后的前20年中，45岁之前被诊断出原发性乳腺癌的患者中，异时性双侧癌症的发病率从每10（5）人年约800例降至每10（5）人年400例，而在诊断时年龄为45岁或以上的患者中，发病率保持在每10（5）人年500至600例。经过30年的随访，无论首例原发性乳腺癌的年龄如何，异时性双侧乳腺癌的累积风险约为15%。
同步双侧乳腺癌高于预期的风险可能由非遗传因素解释。相比之下，异时性双侧癌症的发病率既不符合高穿透性基因模型，也不符合环境风险因素的聚集情况。
