乳腺癌是全世界女性最常见的癌,约占女性癌症的 25%,北美洲、西欧、北欧及澳大利亚发病比例较高。[4]Althuis MD, Dozier JM, Anderson WF, et al. Global trends in breast cancer incidence and mortality 1973-1997. Int J Epidemiol. 2005;34:405-412.http://ije.oxfordjournals.org/content/34/2/405.fullhttp://www.ncbi.nlm.nih.gov/pubmed/15737977?tool=bestpractice.com 因乳腺癌致死者,在英国每年约 15,000 例,世界范围内死亡病例与发病数之间的比例约为 36%。[5]Pisani P, Parkin DM, Ferlay J. Estimates of the worldwide mortality from eighteen major cancers in 1985. Implications for prevention and projections of future burden. Int J Cancer. 1993;55:891-903.http://www.ncbi.nlm.nih.gov/pubmed/8253525?tool=bestpractice.com 据估计,最近 5 年内确诊为乳腺癌的女性中,约有 390 万仍存活。由于部分女性带病存活多年,因此转移性乳腺癌的发病率甚至更高。[6]Parkin DM. Global cancer statistics in the year 2000. Lancet Oncol. 2001;2:533-543.http://www.ncbi.nlm.nih.gov/pubmed/11905707?tool=bestpractice.com 乳腺癌的发生率、尤其是雌激素受体阳性者自 2003 年起已经有所降低。这被认为是由于乳腺影像学筛查模式的改变及激素替代治疗应用减少所致。[7]Glass AG, Lacey JV Jr, Carreon JD, et al. Breast cancer incidence, 1980-2006: combined roles of menopausal hormone therapy, screening mammography, and estrogen receptor status. J Natl Cancer Inst. 2007;99:1152-1161.http://www.ncbi.nlm.nih.gov/pubmed/17652280?tool=bestpractice.com 要确定乳腺癌发生率的降低会导致乳腺癌死亡的减少,还为时过早。
首诊发现乳腺转移性病变或推测病变局限于局部而治疗后发现的乳腺转移性病变,占乳腺癌患者的 40%。[8]Early Breast Cancer Trialists' Collaborative Group (EBCTCG). Effects of chemotherapy and hormonal therapy for early breast cancer on recurrence and 15-year survival: an overview of the randomised trials. Lancet. 2005;365:1687-1717.http://www.ncbi.nlm.nih.gov/pubmed/15894097?tool=bestpractice.com 转移性乳腺癌患者的中位存活时间为 2-3 年,5 年存活率为 24%。[9]American Cancer Society. Cancer facts and figures 2014. http://www.cancer.org (last accessed 17 May 2017).http://www.cancer.org/acs/groups/content/@research/documents/webcontent/acspc-042151.pdf[10]Greenberg PA, Hortobagyi GN, Smith TL, et al: Long-term follow-up of patients with complete remission following combination chemotherapy for metastatic breast cancer. J Clin Oncol. 1996,14:2197-2205.http://www.ncbi.nlm.nih.gov/pubmed/8708708?tool=bestpractice.com