Parazzini F, La Vecchia C, Negri E
Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
Int J Cancer. 1991 Jul 30;48(6):816-20. doi: 10.1002/ijc.2910480605.
The relationship between spontaneous or induced abortion and the risk of breast cancer was analyzed in a case-control study conducted in the greater Milan area on 2,394 cases of breast cancer and 2,218 controls in hospital for a spectrum of acute conditions, not gynecological, hormonal or neoplastic. No consistent relationship emerged between spontaneous or induced abortion and breast cancer: compared with women reporting no abortions (spontaneous or induced), the multivariate relative risk (RR) was 1.0 (95% confidence interval, CI, 0.9 to 1.2) in those reporting one abortion and 0.9 (95% CI 0.7 to 1.0) in those reporting two or more. This lack of association was consistent in strata of age and parity, including younger women. We further analyzed the risk of breast cancer associated with an abortion before and after full-term pregnancy. Compared with parous women reporting no induced or spontaneous abortions, those who had an abortion before their first full-term pregnancy had about a 20% higher risk of breast cancer. This finding, however, was not statistically significant (RR 1.2, 95% CI 0.9 to 1.7). No increased risk was observed in women who had had a first abortion after a full-term pregnancy (RR 0.9, 95% CI 0.8 to 1.0). This study does not support the hypothesis that spontaneous or induced abortion appreciably influences subsequent breast-cancer risk.
在大米兰地区进行的一项病例对照研究中，分析了自然流产或人工流产与患乳腺癌风险之间的关系。该研究选取了2394例乳腺癌患者和2218例因一系列非妇科、非激素及非肿瘤性急性疾病住院的对照者。自然流产或人工流产与乳腺癌之间未呈现出一致的关系：与未报告有流产（自然流产或人工流产）的女性相比，报告有一次流产的女性多变量相对风险（RR）为1.0（95%置信区间[CI]为0.9至1.2），报告有两次或更多次流产的女性RR为0.9（95%CI为0.7至1.0）。这种缺乏关联在包括年轻女性在内的年龄和生育胎次分层中是一致的。我们进一步分析了与足月妊娠前后流产相关的乳腺癌风险。与报告无人工流产或自然流产的经产妇相比，在首次足月妊娠前有过流产的女性患乳腺癌的风险高出约20%。然而，这一发现无统计学意义（RR为1.2，95%CI为0.9至1.7）。在足月妊娠后首次流产的女性中未观察到风险增加（RR为0.9，95%CI为0.8至1.0）。本研究不支持自然流产或人工流产会显著影响后续患乳腺癌风险这一假说。
