Yuen J, Persson I, Bergkvist L, Hoover R, Schairer C, Adami H O
Cancer Epidemiology Unit, Uppsala University, Sweden.
Cancer Causes Control. 1993 Jul;4(4):369-74. doi: 10.1007/BF00051340.
No change of breast cancer mortality has been reported previously after long-term hormone replacement therapy. A conceivable explanation for the apparent discrepancy between incidence and mortality may be selection bias due to lower prevalence of breast cancer in women who receive replacement hormones, compared with nonexposed women. We used a new approach to correct for bias due to this 'healthy drug-user effect,' by adjusting the external, population-based, mortality rates for such cases prevalent during the recruitment period of our cohort. In this cohort of some 23,000 Swedish women, who were prescribed various hormone replacement regimens, breast cancer mortality was analyzed after follow-up to 12 years. External analyses revealed overall standardized mortality ratios for breast cancer rising from 0.71 to 0.81, but not significantly different from unity, after adjustment procedures. In multivariate regression models, excluding prevalent cases in the cohort, women prescribed estradiol, conjugated estrogens, or an estrogen-progestin combination were not at a higher risk relative to those given other and weak estrogens, relative risks being 0.81 and 0.68, respectively. On the basis of the present analytical approach, we conclude that breast cancer mortality does not appear to be changed overall or in subgroups, despite increased incidence.
此前尚无长期激素替代疗法后乳腺癌死亡率变化的相关报道。对于发病率与死亡率之间明显差异的一种可能解释是，与未接受替代激素的女性相比，接受替代激素的女性中乳腺癌患病率较低，从而导致选择偏倚。我们采用了一种新方法来校正由于这种“健康药物使用者效应”导致的偏倚，即对我们队列招募期间存在的此类病例，调整基于人群的外部死亡率。在这个约有23000名瑞典女性的队列中，她们被开具了各种激素替代方案，随访12年后分析了乳腺癌死亡率。外部分析显示，调整程序后，乳腺癌的总体标准化死亡率从0.71升至0.81，但与1无显著差异。在多变量回归模型中，排除队列中的现患病例后，开具雌二醇、结合雌激素或雌激素 - 孕激素组合的女性相对于给予其他弱雌激素的女性，风险并未更高，相对风险分别为0.81和0.68。基于目前的分析方法，我们得出结论，尽管发病率有所增加，但乳腺癌死亡率在总体或亚组中似乎并未改变。
